JP2018091855A - Distance detection device and distance detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tremor correction device and range-finding meter that can resolve a disadvantage in which a correction lens is driven in spite of the fact that a tremor is intentional panning of users.SOLUTION: A tremor correction device comprises: a collimation optical system 300 that collimates an object to form an optical image of a collimation object; a range-finding signal processing unit 700 that repetitively range-finds with respect to the collimation object, and sequentially outputs range-finding signals; a tremor detection unit 400 that detects a tremor to be applied to the collimation optical system, and outputs a tremor signal; a correction member that is disposed in an optical path of the collimation optical system, and corrects an image tremor of the optical image attributed to the tremor to be applied o the collimation optical system; an amount-of-drive calculation unit 500 that calculates an amount of drive of the correction member on the basis of the output from the range-finding signal processing unit and the tremor signal from the tremor detection unit; and a driving unit 620 that drives the correction member on the basis of the calculated amount of drive.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shake correction apparatus and a rangefinder.

An image blur prevention device that controls the operation of a blur correction unit based on an angular velocity signal from a gyro sensor and a distance to a subject is known (see Patent Document 1).
[Patent Document 1] JP2011-23988A

  Some image blur prevention devices drive the correction lens according to the output from the gyro sensor and the distance to the subject. However, there is a problem that the correction lens is driven even though the blur is intentional panning of the user.

  The shake correction apparatus according to the first aspect of the present invention includes a collimation optical system that collimates an object to form an optical image of the collimation target, and repeats ranging with respect to the collimation target to generate a ranging signal. Sequential output ranging signal processing unit and shake applied to collimation optical system are detected, shake detection unit outputting shake signal and optical path of collimation optical system are caused by shake applied to collimation optical system A correction member that corrects an image shake of the optical image, a drive amount calculation unit that calculates a drive amount of the correction member based on an output from the ranging signal processing unit and a shake signal from the shake detection unit, and a calculated drive And a drive unit that drives the correction member based on the amount.

  A rangefinder according to a second aspect of the present invention includes the above shake correction device, a light transmission unit that emits measurement light to the collimation target, and a light reception signal that receives return light from the collimation target. The ranging signal processing unit calculates the distance of the collimation target based on the timing when the measurement light is emitted and the timing when the light receiving unit receives the return light.

  The summary of the invention does not enumerate all the features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

1 is a block diagram of a rangefinder 10 according to the present invention. 6 is a block diagram of a portion related to the calculation of a shake angular velocity ω inside the drive amount calculation unit 500. FIG. It is a figure explaining the effect of cut-off frequency fc. 6 is a block diagram of a portion related to the calculation of a correction lens target position LC within the drive amount calculation unit 500. FIG. It is a figure explaining the relationship between angular velocity bias amount omegabias and correction lens target position LC. FIG. 5 is a flowchart for explaining the operation of the distance meter 10. It is a flowchart explaining the moving body flag determination process of the distance meter. It is a figure which shows an example of the ranging sampling result at the time of panning non-detection. It is a figure which shows an example of the ranging sampling result at the time of panning detection. It is the table | surface which put together the combination of the parameter determined by the collimation change determination flag and moving body flag in this embodiment. It is a flowchart explaining the shake correction process of the distance meter. It is a flowchart explaining the shake correction process of the distance meter.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is a block diagram of a rangefinder 10 according to the present embodiment. The rangefinder 10 includes a light transmitting unit 100, a light receiving unit 200, a collimating optical system 300, a shake detecting unit 400, a driving amount calculating unit 500, a correcting unit 600, a ranging signal processing unit 700, a control unit 800, and operation buttons 900. Is provided.

The light transmitting unit 100 emits measurement light forward. The light sending unit 100 includes an objective lens 110, a correction lens 610, an erecting prism 120, and a light emitting unit 130. In the following description, the direction in which the light-sending part 100 in distance meter 10 emits a measuring light, that is, when that forward arrow direction of a light ray B ₃ in FIG.

  The light emitting unit 130 emits a predetermined number of pulsed measurement lights per unit time. In this case, the light emitting unit 130 emits, for example, hundreds to thousands of pulsed light as measurement light per second. An example of the light emitting unit 130 is a semiconductor laser that oscillates light in the infrared region. Hereinafter, the light emitting unit 130 will be described using an example in which measurement light in the infrared region is emitted.

The erecting prism 120 reflects the light in the visible light band and transmits the infrared light, and the total reflection having a high reflectance for the light in the infrared band in addition to the visible light band. Surfaces 124 and 126. Measuring light transmitted through the dichroic reflection surface 122, is reflected by the total reflection surface 124, propagating distance meter 10 toward the front as light ray B _2. Further, the erecting prism 120 uses the dichroic reflecting surface 122, the total reflecting surfaces 124 and 126, and other reflecting surfaces to invert the inverted mirror image formed by the incident light beam to an erecting image. Examples of the erecting prism 120 are a roof prism, a porro prism, and the like.

  The objective lens 110 is disposed at the front end of the rangefinder 10, and the front end face is opposed to the object to be measured. In the following description, an object to be measured may be referred to as an object or a collimation object. The rear end face of the objective lens 110 faces the front end face of the erecting prism 120 with the correction lens 610 interposed therebetween.

  The light receiving unit 200 receives incident light incident from the front, converts an intensity signal of the incident light into an electric signal, and outputs the electric signal. The light receiving unit 200 includes a light receiving lens 210, a band transmission filter 220, and a light receiving element 230, which are optical systems separate from the light transmitting unit 100 and the collimating optical system 300. Accordingly, the light receiving unit 200 has an optical axis different from that of the light transmitting unit 100 and the collimating optical system 300.

  A band transmission filter 220 and a light receiving element 230 are sequentially arranged behind the light receiving lens 210. The band transmission filter 220 transmits light in a narrow wavelength band including measurement light, and blocks or attenuates light in other wavelength bands. An example of the light receiving element 230 is a photodiode, a phototransistor, or the like having sensitivity to the wavelength band of the measurement light. From the viewpoint of eliminating the influence of background light on the measurement light, the light receiving area of the light receiving element 230 is preferably smaller.

In the light receiving unit 200, a light beam C ₁ reflected or scattered from an object located in front of the rangefinder 10 is incident on the light receiving lens 210. The light beam C ₁ is collected by the light receiving lens 210, propagates backward as the light beam C ₂ , passes through the band transmission filter 220, and is received by the light receiving element 230.

  The light receiving element 230 converts the received optical signal into an electrical signal corresponding to the intensity, amplifies the signal with an internal amplifier, and then outputs the electrical signal to the ranging signal processing unit 700.

  The ranging signal processing unit 700 calculates the distance to the collimated object based on the timing when the measurement light is emitted and the timing when the light receiving unit 200 receives the incident light. The ranging signal processing unit 700 includes a binarization circuit, a sampling circuit, a counter circuit, an oscillator, and the like. The electric signal from the light receiving element 230 is converted into a binarized signal in accordance with a predetermined threshold value in the binarizing circuit and output to the sampling circuit. A sampling clock having a specific frequency is input from the oscillator to the sampling circuit. The count value is input to the sampling circuit from the counter circuit. The sampling circuit performs digital sampling of the input binarized signal and generates a light reception signal synchronized with the sampling clock. The count value is reset by the control unit 800 at the timing when pulsed light is emitted from the light emitting unit 130.

  The ranging signal processing unit 700 calculates the time difference between the time when the light emitting unit 130 emits the pulsed light and the time when the light receiving element 230 receives incident light reflected from the object, based on the count value in the pulse of the received light signal. To do.

  The ranging signal processing unit 700 sequentially executes time difference calculation processing on each pulsed light of the measurement light in the same manner. Each time the pulse time difference in the received light signal is calculated, the signal value is integrated to the memory address corresponding to the time difference in its own internal memory. Thereby, a histogram for calculating the distance is generated. When the processing is completed for the received light signals corresponding to a predetermined number of pulse lights, the ranging signal processing unit 700 specifies the memory address having the maximum integrated value. The ranging signal processing unit 700 recognizes the time difference Δt corresponding to the memory address as the time difference between light transmission and reception corresponding to the object.

The ranging signal processing unit 700 calculates the distance to the object based on the recognized time difference Δt. Specifically, the ranging signal processing unit 700 converts the time difference into a distance using the following equation.
l = c × Δt / 2
Here, l is the distance to the object, and c is the speed of light. The ranging signal processing unit 700 sends information on the calculated distance l to the object to the control unit 800.

  In the present embodiment, the ranging signal processing unit 700 repeats ranging with respect to the collimation target, and sequentially outputs ranging signals. Here, the distance measurement signal is the time of the distance of the object sequentially calculated from the time difference between the time when the light emitting unit 130 emits the pulsed light and the time when the light receiving element 230 receives incident light reflected or the like from the object. It is a signal indicating a change. The ranging signal processing unit 700 outputs the ranging signal to the driving amount calculating unit 500 via the control unit 800.

  The control unit 800 comprehensively controls the ranging operation in the rangefinder 10. Control targets of the control unit 800 include the light transmitting unit 100, the light receiving unit 200, the ranging signal processing unit 700, and the like. The control unit 800 shows information such as the distance to the object calculated by the ranging signal processing unit 700 to the user on the reticle plate 320 with characters, images, and the like.

  The collimation optical system 300 collimates the object and forms an optical image of the collimation target. The collimation optical system 300 includes a reticle plate 320 and an eyepiece lens 310. The collimation optical system 300 further shares the objective lens 110, the correction lens 610, and the erecting prism 120 with the light transmitting unit 100. Thereby, the apparent optical axes of the light transmitting unit 100 and the collimating optical system 300 coincide. The user observes the front through the collimation optical system 300 and determines the collimation for the object.

  The reticle plate 320 is arranged at the focal position of the objective lens 110 of the light transmitting unit 100. The front end of the eyepiece 310 faces the rear end of the reticle plate 320 inside the rangefinder 10. Reticle plate 320 has a collimation index and a display unit. Examples of the shape of the collimation index are a crosshair, a rectangular frame, a circular frame, and the like. The display unit uses a transmissive liquid crystal or the like to show the measurement result of the distance to the object to the user by characters, images, and the like.

The collimation optical system 300, of the reflected or scattered light from the object located in front of the distance meter 10, light rays A ₁ propagating within the viewing angle of the objective lens 110 is incident. The light ray A ₁ is condensed as the light ray A ₂ by the objective lens 110, and is emitted as the light ray A ₃ behind the rangefinder 10 through the erecting prism 120, the reticle plate 320 and the eyepiece lens 310. Thereby, the user observes an erect image of the object through the eyepiece lens 310.

  A collimation index disposed on the reticle plate 320 is superimposed on an image observed by the user through the eyepiece 310. The user collimates the rangefinder 10 by orienting the collimator so that the collimation index is superimposed on the image of the object observed through the eyepiece 310. In this case, since the apparent optical axes of the light transmitting unit 100 and the collimation optical system 300 coincide with each other as described above, the measurement light is irradiated to the position indicated by the collimation index.

  The shake detection unit 400 includes a plurality of angular velocity sensors whose detection directions intersect each other. The plurality of angular velocity sensors are arranged in a direction in which pitching and yawing of the rangefinder 10 are detected, for example. Each of the angular velocity sensors detects the shake when the rangefinder 10 is shaken, and outputs a shake signal corresponding to the shake amount including the direction, size, and frequency to the drive amount calculation unit 500 as information. To do.

  The drive amount calculation unit 500 periodically refers to the shake signal output from the shake detection unit 400 to calculate a drive amount that is a displacement amount of the correction lens 610. The driving amount is an amount by which the correction lens 610 is displaced in order to cancel out the image shake of the optical image generated in the collimation optical system 300 due to the displacement of the rangefinder 10. The driving amount includes direction and size information. The drive amount calculation unit 500 outputs a drive signal for driving the correction lens 610 with the drive amount to the drive unit 620.

  In the present embodiment, the drive amount calculation unit 500 drives the correction lens 610 to be driven by the correction unit 600 based on the combination of the output from the ranging signal processing unit 700 and the shake detection signal from the shake detection unit 400. The amount is calculated and output to the correction unit 600. In particular, in the present embodiment, as an example of the output from the ranging signal processing unit 700, a temporal change in the distance calculated by the ranging signal processing unit 700 is used.

  The drive unit 620 displaces the correction lens 610 in a direction intersecting the optical axis based on the drive signal received from the drive amount calculation unit 500. For the drive unit 620, for example, a voice coil motor, a piezoelectric motor, or the like can be used.

  The position detection unit 630 periodically detects the position of the correction lens 610 and outputs a position signal that is a signal corresponding to the position to the drive amount calculation unit 500 and the control unit 800. For the position detection unit 630, for example, an optical position detection sensor or the like can be used in addition to a magnetic sensor using a Hall element or an MR element.

  The drive amount calculation unit 500 feedback-controls the drive amount of the correction lens 610 according to the position signal of the correction lens 610 acquired from the position detection unit 630. Thereby, even when a disturbance such as impact or vibration is applied, the position of the correction lens 610 can be accurately controlled.

  The correction unit 600 drives the correction lens 610 with a drive amount corresponding to the shake of the optical axis of the collimation optical system 300. The correction unit 600 includes a correction lens 610, a drive unit 620, and a position detection unit 630.

  The correction unit 600 may always perform the correction operation, but may perform the correction operation only during a period in which the user is using the rangefinder 10. For example, the user's eyes looking through the eyepiece 310 may be detected to determine whether or not the user is using the rangefinder 10. Then, when it is determined that the user is using the rangefinder 10, the correction unit 600 may be turned on / off. Further, the correction unit 600 may start the operation based on the operation of the operation button 900 by the user. Thereafter, the operation of the correction unit 600 may be stopped when there is no user operation beyond a predetermined time.

The correction lens 610 is driven by the drive unit 620 in the vicinity of the objective lens 110 to displace the optical paths of the light beams A ₂ and B ₂ . As a result, when the distance meter 10 is displaced, the correction lens 610 is displaced so as to optically cancel the displacement, whereby blurring of an image observed by the user can be stopped. Since the correction lens 610 is shared by the light transmission unit 100, even if the distance meter 10 is displaced, the same object can be continuously irradiated with the measurement light.

  FIG. 2 is a block diagram of a portion related to the calculation of the shake angular velocity ω inside the drive amount calculation unit 500. FIG. 2 shows processing inside the drive amount calculation unit 500. As shown in FIG. 2, the drive amount calculation unit 500 includes an A / D converter 502, a shake angular velocity reference value calculation unit 504, a subtraction unit 506, a collimation change detection unit 508, an fc designation unit 510, a memory 512, and an LPF. A processing unit 514 is included.

  The shake detection unit 400 detects an angular velocity due to camera shake that has occurred in the rangefinder 10, and outputs a shake detection signal that is a signal corresponding to the detection result to the drive amount calculation unit 500. The drive amount calculation unit 500 calculates a shake angular velocity ω to determine the drive amount of the correction lens 610 from the shake detection signal. Specifically, the drive amount calculation unit 500 converts the shake detection signal into a shake quantized value ω1 quantized by the internal A / D converter 502. Next, the shake angular velocity reference value calculation unit 504 performs LPF calculation on the shake angular velocity reference value ω0 serving as a reference for the shake quantized value ω1 from the shake quantized value ω1 using the cutoff frequency fc. Then, the subtraction unit 506 calculates the shake angular velocity ω by subtracting the shake angular velocity reference value ω0 from the shake quantized value ω1. Note that the process of calculating the shake angular velocity ω from the shake quantized value ω1 removes the low frequency component of the shake quantized value ω1, and is substantially an HPF process.

  The collimation change detection unit 508 detects collimation change based on the magnitude of the shake signal from the shake detection unit. The collimation change detection unit 508 determines whether or not collimation is being changed from the absolute value of the shake angular velocity ω, and stores a collimation change flag corresponding to the determination result in the memory 512. The determination uses a collimation change start threshold Panωth_s and a collimation change end threshold Panωth_e, which are predetermined angular velocity thresholds. The collimation change detection unit 508 determines that collimation change has started when the shake angular velocity ω exceeds Panωth_s. Thereafter, when the shake angular velocity ω falls below Panωth_e, it is determined that the collimation change has been completed.

  The collimation change flag is set to 1, for example, when it is determined that the collimation is being changed. On the other hand, when it is determined that the collimation is not being changed, 0 is set. Note that a default value is set for the collimation change flag, and, for example, 0 is set when the rangefinder 10 is activated.

  The memory 512 also stores a moving object flag to be described later. The moving object flag is set according to a temporal change in the distance to the object obtained by distance measurement. In the following description, the collimation change flag and the moving object flag may be collectively referred to as flag information. Further, in addition to the flag information that is sequentially updated, the memory 512 has a predetermined cutoff frequency fc, a bias coefficient Kbias described later, a correction range, and the like based on a combination of a collimation change flag and a moving object flag. Parameter information is stored. In addition, the memory 512 stores a default value of the parameter and various threshold information described later.

  The driving amount calculation unit 500 refers to the flag information from the memory 512 and outputs information on a predetermined cutoff frequency fc to the fc designation unit 510. The fc designation unit 510 designates the cutoff frequency fc in the process of the LPF processing unit 514. The LPF processing unit 514 calculates a shake angular velocity reference value ω0 from the shake quantized value ω1 using the cutoff frequency fc. Note that a default value is set for the cutoff frequency fc, and the default value is, for example, 0.1 Hz.

  FIG. 3 is a diagram for explaining the effect of the cutoff frequency fc. FIG. 3A shows the shake quantized value ω1 acquired in time series. This shows that the collimation has been changed from a state in which the collimation is relatively stable. FIG. 3B shows the shake angular velocity ω obtained by HPF processing at the cutoff frequency fc = 0.1 Hz with respect to the shake quantization value ω1. FIG. 3C shows the shake angular velocity ω obtained by the HPF process at the cutoff frequency fc = 1.0 Hz with respect to the shake quantized value ω1.

  The rangefinder 10 calculates the target position of the correction lens 610 with respect to the shake angular velocity ω. In FIG. 3B, since HPF processing is performed at a relatively low frequency of 0.1 Hz, a relatively large angular velocity component due to panning remains in the shake to be corrected. On the other hand, in FIG. 3C, since the HPF process is performed at a relatively high frequency of 1.0 Hz, the component of the large angular velocity is removed, and the shake to be corrected is mostly a shake. It is only the component which originates.

  Correcting all the shakes occurring in the rangefinder 10 may cause inconvenience in use. For example, when the panning is intended by the user and the operation is performed so as to correct the shake caused by the panning, the followability to the object is impaired. As a result, there is a possibility that the object cannot be captured in collimation. Therefore, in this embodiment, when it is determined that the collimation is being changed, the cutoff frequency fc is set higher than the default value, and a large shake angular velocity is corrected as shown in FIG. Exclude from the target.

  Furthermore, in the present embodiment, the drive amount calculation unit 500 sequentially changes the value of the cutoff frequency fc according to the temporal change in the distance measurement result. Details will be described later.

  FIG. 4 is a block diagram of a portion related to the calculation of the correction lens target position LC inside the drive amount calculation unit 500. As shown in FIG. 4, the drive amount calculation unit 500 includes a memory 512, a subtraction unit 516, an integration unit 518, a multiplication unit 520, a movable range restriction unit 522, and a bias calculation unit 524.

  The drive amount calculation unit 500 calculates the correction lens target value LC from the shake angular velocity ω. Specifically, first, the drive amount calculation unit 500 calculates the angle by integrating the shake angular velocity ω with time by the integration unit 518. Next, a multiplier 520 multiplies the angle by a coefficient KLC to calculate a corrected lens target position LC. The coefficient KLC is a conversion coefficient determined from the focal length of the correction lens 610 and the like.

  In order for the shake correction to be performed appropriately, the correction lens target position LC must be within the movable range of the correction lens 610. When the user changes the collimation, a large shake angular velocity may occur in the rangefinder 10. At this time, as a result of performing shake correction for the large shake angular velocity, the correction lens 610 may reach the physical movable range. When the correction lens 610 reaches the physical movable range, further shake correction operation is restricted.

  Therefore, the movable range limiter 522 converts the correction lens target position LC so as not to exceed a predetermined movable limit range that is narrower than the physical movable range, thereby moving to the physical movable range. This prevents the correction lens 610 from touching. In the present embodiment, the drive amount calculation unit 500 appropriately switches the correction range that is the movable limit range according to the flag information stored in the memory 512.

  In the present embodiment, the drive amount calculation unit 500 restricts the drive amount of the correction lens 610 by changing the value of the angular velocity bias ωbias that acts to bring the correction lens target position LC closer to the center of the movable range. Here, the angular velocity bias ωbias is a function of the distance from the movable center of the correction lens 610 to the correction lens target position LC. Details will be described later.

  Specifically, a process of subtracting the angular velocity bias amount ωbias from the shake angular velocity ω is performed. This processing is performed by the bias calculation unit 524 and the subtraction unit 516. Then, the correction lens target position LC is recalculated using the differential angular velocity ω ′ obtained by the processing. The drive amount calculation unit 500 calculates the drive amount of the correction lens 610 from the correction lens target position LC.

  FIG. 5 is a diagram for explaining the relationship between the angular velocity bias amount ωbias and the correction lens target position LC. The vertical axis represents the angular velocity bias ωbias. The horizontal axis indicates the lens target position LC. The correction lens 610 is driven within the correction lens movable range.

When the center of the movable range of the correction lens 610 is set to 0, the angular velocity bias amount ωbias that is the output of the bias calculation unit 524 is calculated by the following equation (1). Here, the coefficient Kbias is a predetermined coefficient. In the following description, Kbias may be referred to as a bias coefficient. Further, the output ω ′ of the subtraction unit 516 is calculated by the following equation (2).
ωbias = Kbias × LC ³ (1)
ω ′ = ω−ωbias (2)

  From the above equation (1), when the correction lens target position LC is close to the center of the movable range of the correction lens 610, the contribution to the angular velocity bias ωbias is small. On the other hand, as the correction lens target position LC is further away from the center of the movable range, the contribution to the angular velocity bias amount ωbias increases. For this reason, ω ′ obtained by the above equation (2) decreases as the correction lens target position LC moves away from the center of the movable range. Therefore, the corrected lens target position LC newly calculated from ω ′ is close to the center of the movable range. That is, the correction lens 610 is returned to the center of the movable range.

  When the angular velocity bias amount ωbias is reduced, shake correction is performed even for a large shake, so that the followability of the optical axis of the collimation optical system 300 is deteriorated with respect to the user's collimation operation, but the shake correction effect is increased. . On the other hand, when the angular velocity bias amount ωbias is increased, shake correction is not performed for large shakes, so that the followability of the optical axis of the collimation optical system 300 is improved with respect to the user's collimation operation. descend.

  As can also be seen from FIG. 5, when the bias coefficient Kbias is changed in the above equation (1), the angular velocity bias amount ωbias calculated for the same correction lens target position LC changes. In this way, it is possible to adjust the degree of contribution of the calculated correction lens target position LC to the angular velocity bias ωbias using the bias coefficient Kbias. In the present embodiment, the drive amount calculation unit 500 switches the bias coefficient Kbias as appropriate based on the flag information stored in the memory 512.

  FIG. 6 is a flowchart for explaining the operation of the distance meter 10. This flow starts when the power of the rangefinder 10 is turned on by the user pressing the operation button 900. The rangefinder 10 starts a moving object flag determination process (S100) and a shake correction process (S200), which will be described later. Specifically, when the power is turned on by the user, control unit 800 outputs a drive signal to drive amount calculation unit 500. When the drive signal is input, the drive amount calculation unit 500 starts the processes of step S100 and step S200.

  When the moving body flag determination process (S100) ends, the process proceeds to step S300, and it is determined whether or not a predetermined time has elapsed since the last operation of the operation button 900 by the user (S300). ). The predetermined time is a time necessary and sufficient for completing the distance measuring operation. When it is determined that a predetermined time has elapsed (S300: YES), the drive amount calculation unit 500 ends this flow. Specifically, control unit 800 outputs a drive stop signal to drive amount calculation unit 500. When the drive stop signal is input, the drive amount calculation unit 500 ends the processes of Step S100 and Step S200.

  On the other hand, when it is determined that the predetermined time has not elapsed (S300: NO), the drive amount calculation unit 500 continues the processing of step S100 and step S200. Therefore, this flow is always executed when the power of the rangefinder 10 is ON.

  FIG. 7 is a flowchart for explaining the moving object flag determination process of the distance meter 10. As described with reference to FIG. 6, this flow starts when the distance meter 10 is turned on by the user pressing the operation button 900.

  The ranging signal processing unit 700 executes the ranging operation described with reference to FIG. 1 and calculates a distance Dist to the object (S101). Then, the distance measurement signal processing unit 700 outputs the Dist to the driving amount calculation unit 500 via the control unit 800. At this time, the driving amount calculation unit 500 determines whether or not a value is stored in Dist_buf (S102). Here, Dist_buf is a variable created in the memory 512 inside the drive amount calculation unit 500. Dist_buf is initialized by deleting data stored when the distance meter 10 is activated.

  When it is determined that no value is stored in Dist_buf (S102: NO), the drive amount calculation unit 500 stores Dist in Dist_buf (S103), and proceeds to step S101. On the other hand, when it is determined that a value is stored in Dist_buf (S102: YES), the drive amount calculation unit 500 adds the absolute value data of the difference between Dist_buf and Dist to the distance difference data ΔDist, that is, the time of the distance. The amount of change data is stored (S104). Here, ΔDist is a variable created in the memory 512 similarly to Dist_buf.

  The driving amount calculation unit 500 stores Dist in Dist_buf (S105). Note that the value stored in Dist_buf is overwritten by the newly stored Dist.

  The driving amount calculation unit 500 determines whether ΔDist is below a predetermined threshold Target_th1 (S106). If it is determined that ΔDist is below a predetermined threshold Target_th1 (S106: YES), it is determined that the object is stationary, and the moving object flag stored in the memory 512 is set to 0. (S107). Note that a default value is set for the moving object flag, and, for example, 0 is set when the rangefinder 10 is activated.

  On the other hand, when it is determined that ΔDist is not lower than the predetermined threshold Target_th1 (S106: NO), the drive amount calculation unit 500 determines whether ΔDist is lower than the predetermined threshold Target_th2. (S108).

  When it is determined that ΔDist is lower than the predetermined threshold Target_th2 (S108: YES), the drive amount calculation unit 500 determines that the object is moving in the front-rear direction and stores it in the memory 512. The moving object flag that has been set is set to 1 (S109). On the other hand, when it is determined that ΔDist is not lower than the predetermined threshold Target_th2 (S108: NO), the drive amount calculation unit 500 determines that the collimation has been lost from the object and is stored in the memory 512. The moving object flag is set to 2 (S110).

  When the moving object flag is determined and the setting to the memory 512 is completed, this flow ends. And it transfers to step S300 of the flow of FIG.

  Next, a method of determining the collimation change flag according to the distance measurement result and the temporal change of the shake angular velocity ω will be described with reference to FIGS. 8 and 9, the horizontal axis represents time, and the vertical axis represents the temporal change in distance and angular velocity. The moving body flag shown in FIG. 7 will also be described.

  FIG. 8 shows an example in which no collimation change is detected during ranging sampling. FIG. 8A shows the time transition of the temporal change amount ΔDist of the distance of the object calculated by the ranging signal processing unit 700. FIG. 8B shows a time transition of the deflection angular velocity ω.

  In FIG. 8A, in the period A, ΔDist is between Target_th1 and Target_th2. For this reason, in the period A, the drive amount calculation unit 500 sets 1 to the moving object flag. In the period B, ΔDist exceeds Target_th2. For this reason, in the period B, the driving amount calculation unit 500 sets 2 to the moving object flag. In the period C, ΔDist is lower than Target_th1. For this reason, in the period C, the driving amount calculation unit 500 sets 0 for the moving object flag.

  In FIG. 8B, there is no period in which the shake angular velocity ω exceeds the collimation change start threshold Panωth_s, and the collimation change flag remains zero.

  In period A, the collimation change flag is set to 0, and the moving object flag is set to 1. It can be seen from FIG. 8A that the distance measurement results are displaced at a constant rate for each time period during the period. In addition, FIG. 8B shows that the collimation is not being changed during the period. From the above, during the period, the object moves in the front-rear direction at a constant speed, but the user can determine that the distance meter 10 can be correctly collimated with respect to the object. Therefore, when the collimation change flag is 0 and the moving object flag is 1, the drive amount calculation unit 500 applies default values to any parameters of the cutoff frequency fc, the bias coefficient Kbias, and the correction range. However, since the object is moving and collimation may be lost, the collimation change start threshold Panωth_s is lowered. As a result, the drive amount calculation unit 500 can quickly detect a collimation change, change parameters such as the cutoff frequency fc to an optimum value, and ensure followability to the object.

  In period B, 0 is set for the collimation change flag and 2 is set for the moving body flag. From FIG. 8A, it can be seen that the distance measurement result fluctuates significantly at the time P in the period. In addition, FIG. 8B shows that the collimation is not being changed during the period. From the above, for example, the user can determine that the distance to the object cannot be measured even though the object is captured as intended. For example, since the viewing angle of the collimation target is small, it is necessary to stabilize the collimation in a narrow range by correcting a lower frequency shake. Therefore, when the collimation change flag is 0 and the moving object flag is 2, the drive amount calculation unit 500 applies a value lower than 0.1 Hz to the cutoff frequency fc in order to increase the correction effect. Also, a value smaller than the default value is applied to the bias coefficient Kbias, and a range wider than the default value is applied to the correction range of the correction lens 610. For example, when the collimation target starts moving, the collimation change start threshold Panωth_s is lowered so that the collimation can be performed quickly. Thereby, when the collimation change is started in response to the movement of the collimation target, the collimation change operation can be quickly detected, and the parameters such as the cut-off frequency fc are changed to the optimum values and the target is changed. It is possible to quickly ensure the ability to follow objects.

  In period C, the collimation change flag and the moving object flag are both set to 0. FIG. 8A shows that the object is stationary during the period. In addition, FIG. 8B shows that collimation is stable during the period. Therefore, when the collimation change flag and the moving object flag are both 0, the drive amount calculation unit 500 applies the default value to any parameter.

  FIG. 9 is a diagram illustrating an example in which collimation change is detected during distance measurement sampling. In the description of FIG. 9, FIGS. 9A and 9B show time transitions of ΔDist and ω, respectively, as in FIG. The description overlapping with FIG. 8 is omitted.

  In FIG. 9A, ΔDist exceeds Target_th2 in periods A and C. For this reason, the drive amount calculation unit 500 sets 2 to the moving body flag in the periods A and C. In the period B, ΔDist is between Target_th1 and Target_th2. For this reason, the drive amount calculation unit 500 sets 1 to the moving object flag in the period B. In the periods D, E, and F, ΔDist is lower than Target_th1. For this reason, the drive amount calculation unit 500 sets the moving object flag to 0 in the periods D, E, and F.

  In FIG. 9B, the shake angular velocity ω exceeds the collimation change start threshold Panωth_s until time P. For this reason, until the time P, the drive amount calculation unit 500 sets the collimation change flag to 1. At time P, the shake angular velocity ω falls below the collimation change end threshold Panωth_e. For this reason, the drive amount calculation unit 500 sets 0 to the collimation change flag.

  In periods A and C, 1 is set for the collimation change flag and 2 is set for the moving body flag. From FIG. 9A, it can be seen that the distance measurement results fluctuate significantly every time during the period. In addition, it can be seen from FIG. 9B that the collimation is being changed during the period. From the above, for example, during the period, the user can perform panning in order to collimate the object, and can determine that the object is not captured well. Therefore, when the collimation change flag is 1 and the moving object flag is 2, the drive amount calculation unit 500 sets the cut-off frequency fc to 1. to reduce the correction effect and ensure followability to the object. A value higher than 0 Hz is applied. Also, a larger value than the default value is applied to the bias coefficient Kbias, and a range narrower than the default value is applied to the correction range of the correction lens 610.

  In period B, 1 is set for both the collimation change flag and the moving object flag. From FIG. 9A, it can be seen that the distance measurement results are displaced at a constant rate for each time period during the period. In addition, it can be seen from FIG. 9B that the collimation is being changed during the period. From the above, for example, the user can perform panning in accordance with the movement of the object during the period, and can determine that the object is well captured. Therefore, when the collimation change flag is 1 and the moving object flag is 1, the drive amount calculation unit 500 applies the default value to any parameter.

  In the period D, 1 is set for the collimation change flag and 0 is set for the moving object flag. From FIG. 9A, it can be seen that the fluctuation of the distance measurement result for each time is slight during the period. In addition, it can be seen from FIG. 9B that the collimation is being changed during the period. From the above, for example, the user can perform panning in accordance with the movement of the object during the period, and can determine that the object is well captured. Therefore, when the collimation change flag is 1 and the moving body flag is 0, the drive amount calculation unit 500 applies the default value to any parameter.

  As described above, in the present embodiment, the drive amount calculation unit 500 dynamically changes the parameter according to the temporal change of the distance of the target object ΔDist and the temporal angular velocity ω.

  FIG. 10 is a table summarizing the combinations of parameters determined by the collimation change determination flag and the moving object flag in the present embodiment. Data in the table shown in FIG. 10 is stored in the memory 512 in advance. When calculating the driving amount of the correction lens 610, the driving amount calculation unit 500 refers to the flag information stored in the memory 512 and the parameter corresponding to the flag information, and sequentially changes the parameter.

  FIGS. 11 and 12 are flowcharts for explaining shake correction processing of the distance meter 10. As described with reference to FIG. 6, this flow starts when the distance meter 10 is turned on by the user pressing the operation button 900.

  The shake detection unit 400 starts shake detection (S201). Then, as described with reference to FIG. 2, the shake detection unit 400 outputs a shake detection signal to the drive amount calculation unit 500. Similarly, as described in FIG. 2, the drive amount calculation unit 500 performs a quantization process and an HPF process on the shake detection signal, and calculates a shake angular velocity ω (S202).

  The drive amount calculation unit 500 determines whether or not the shake angular velocity ω exceeds a predetermined threshold Panωth_s (S203). If it is determined that the shake angular velocity ω does not exceed the predetermined threshold Panωth_s (S203: NO), the process proceeds to step S208 without setting the collimation change flag stored in the memory 512.

  On the other hand, when it is determined that the shake angular velocity ω exceeds the predetermined threshold Panωth_s (S203: YES), that is, when it is determined that the collimation change is started, the drive amount calculation unit 500 stores the memory 512 in the memory 512. The stored collimation change flag is set to 1 (S204). The drive amount calculation unit 500 determines whether or not the moving object flag stored in the memory 512 is 2 (S205).

  When it is determined that the moving object flag is 2 (S205: YES), the drive amount calculation unit 500 applies a value larger than 1.0 Hz to the cutoff frequency fc used in the LPF processing unit 514. Also, a larger value than usual is applied to the bias coefficient Kbias. Further, a narrower range than normal is applied as the correction range (S206). On the other hand, when it is determined that the moving body flag is not 2 (S205: NO), the drive amount calculation unit 500 applies 1.0 Hz to the cutoff frequency fc used in the LPF processing unit 514 (S207).

  Next, the process proceeds to step S208 in FIG. The driving amount calculation unit 500 determines whether or not the collimation change flag stored in the memory 512 is 1 (S208). That is, it is determined whether or not the collimation has been changed in the previous process. If it is determined that the collimation change flag is not 1 (S208: NO), the process proceeds to step S211.

  On the other hand, when it is determined that the collimation change flag is 1 (S208: YES), it is determined whether the shake angular velocity ω is below a predetermined threshold Panωth_e (S209). Here, Panωth_e is an angular velocity threshold value for determining that the collimation change by the user has been completed.

  When it is determined that the shake angular velocity ω is not lower than Panωth_e (S209: NO), the process proceeds to step S216. On the other hand, when it is determined that the shake angular velocity ω is lower than Panωth_e (S209: YES), the drive amount calculation unit 500 sets 0 to the collimation change flag stored in the memory 512 (S210). .

  The drive amount calculation unit 500 determines whether or not the moving object flag is 2 (S211). When it is determined that the moving body flag is 2 (S211: YES), the drive amount calculation unit 500 applies a value smaller than 0.1 Hz to the cutoff frequency fc used in the LPF processing unit 514. A value smaller than the default value is applied to the bias coefficient Kbias. A range wider than usual is applied as the correction range. Further, a smaller value than normal is applied to Panωth_s (S212).

  When it is determined that the moving object flag is not 2 (S211: NO), the drive amount calculation unit 500 determines whether or not the moving object flag is 1 (S213). When it is determined that the moving body flag is 1 (S213: YES), the drive amount calculation unit 500 applies 0.1 Hz to the cutoff frequency fc used in the LPF processing unit 514. A default value is applied to the bias coefficient Kbias. Then, a smaller value than normal is applied to Panωth_s (S214). On the other hand, when it is determined that the moving body flag is not 1 (S213: NO), the drive amount calculation unit 500 applies 0.1 Hz to the cutoff frequency fc used in the LPF processing unit 514. A default value is applied to the bias coefficient Kbias. (S215).

  The drive amount calculation unit 500 calculates the corrected lens target position LC using the parameters determined by the above processing (S216). Then, the drive amount calculation unit 500 performs shake correction by driving the correction lens 610 via the drive unit 620 (S217).

  When the shake correction process is completed, this flow ends. And it transfers to step S300 of the flow of FIG.

  In FIG. 1, the objective lens 110, the light receiving lens 210, and the eyepiece lens 310 are represented by a single lens. However, these lenses may include a plurality of lenses.

  Further, the objective lens 110, the light receiving lens 210, and the eyepiece lens 310 may have variable focal lengths.

  The light emitting unit 130 may emit ultraviolet light instead of emitting infrared light. In this case, the dichroic reflecting surface 122 of the erecting prism 120 in the first embodiment is also compatible with ultraviolet rays.

  In the above description, the state of the object (stationary, moving in the front-rear direction, etc.) is determined according to the relationship with the thresholds Target_th1 and Target_th2 using the temporal change ΔDist of the distance measurement results. It is also possible to calculate a variation in the distance of the target object, for example, RMS (root mean square) and RMS of the change over time of the measurement distance, and to determine these based on a predetermined threshold.

  In the distance measurement for determining the state of the object, distance measurement may be performed with a smaller number of pulses than the number used in the normal distance measurement operation. Furthermore, the present invention is not limited to this, and may be applied to a distance measuring method that does not use a histogram.

  Note that adjustment of control parameters for shake correction operations such as the cut-off frequency fc, the bias coefficient Kbias, and the correction range may be performed for all, or any one or a combination of the two.

  In the above description, the bias coefficient Kbias is used as the control parameter for the shake correction operation. However, the angular velocity bias ωbias itself may be changed.

  In the above description, the control parameter is adjusted according to the time change of the measurement distance. However, the control parameter may be adjusted according to the measured distance to the collimation target. Here, as an example, considering the case where the collimation target is a moving object that moves at a certain speed, the angular velocity added to the rangefinder for collimation becomes smaller as the collimation target is farther away. Become. On the other hand, the closer the collimation target is, the greater the angular velocity added to the rangefinder for collimation. Therefore, for example, the collimation change start threshold is changed according to the distance to the collimation target.

  Specifically, for example, a distance threshold Dth for dividing the distance range into two ranges, a near side and a far side, is determined in advance. Then, it is determined whether or not the distance measurement result is larger than the distance threshold Dth. If it is determined that the distance measurement result is larger than the distance threshold Dth, it is determined that the collimation target is in the far side range, and the collimation change start threshold is increased. On the other hand, when it is determined that the distance measurement result is smaller than the distance threshold Dth, it is determined that the collimation target is in the near side range, and the collimation change start threshold is lowered. By controlling in this way, when a collimation target that is a moving object is at a long distance, a relatively small shake can be corrected and stable collimation can be performed. On the other hand, when the collimation target that is a moving object is at a short distance, it is possible to ensure followability to the collimation target.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The execution order of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior”. It should be noted that they can be implemented in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. is not.

10 rangefinder, 100 light transmission unit, 110 objective lens, 120 erecting prism, 122 dichroic reflection surface, 124, 126 total reflection surface, 130 light emission unit, 200 light reception unit, 210 light reception lens, 220 band transmission filter, 230 light reception Element, 300 collimation optical system, 310 eyepiece, 320 reticle plate, 400 shake detection unit, 500 drive amount calculation unit, 502 A / D converter, 504 shake angular velocity reference value calculation unit, 506 subtraction unit, 508 change collimation Detection unit, 510 fc designation unit, 512 memory, 514 LPF processing unit, 516 subtraction unit, 518 integration unit, 520 multiplication unit, 522 movable range limitation unit, 524 bias calculation unit, 600 correction unit, 610 correction lens, 620 drive unit 630 Position detection unit, 700 Ranging signal processing unit, 800 control Department, 900 operation button

The present invention relates to a distance detection device and a distance detection method .

The distance detection apparatus according to the first aspect of the present invention includes a calculation unit that calculates a distance to a detection target using a time until the projected light is received by the light receiving unit, a sensor that detects blur, A signal processing unit that calculates a time change of the distance using the distance, a driving unit that drives the blur correction optical system, and a control unit that controls the driving unit based on the output of the sensor and the output of the signal processing unit. .

The distance detection device according to the second aspect of the present invention includes a calculation unit that calculates a distance to a detection target using a time until the projected light is received by the light receiving unit, a sensor that detects blur, Based on the sensor output and distance, it is judged whether the collimation is being changed from the detection target to the new detection target and / or whether the detection target is moving, and the drive amount of the blur correction optical system A drive amount calculation unit that calculates the image quality, a drive unit that drives the shake correction optical system, and a control unit that controls the drive unit based on the output of the determination unit.
The distance detection method according to the third aspect of the present invention includes a step of calculating a distance to a detection target using a time until the projected light is received by the light receiving unit, a step of detecting blur, and a distance A step of calculating a temporal change in distance using the method, a step of driving the blur correction optical system, a step of detecting the blur and a step of calculating the temporal change of the distance, and a step of controlling the drive of the blur correction optical system And including.
The distance detection method according to the fourth aspect of the present invention includes a step of calculating a distance to a detection target using a time until the projected light is received by the light receiving unit, a step of detecting blur, Detecting whether or not collimation is being changed from a detection target to a new detection target and / or whether or not the detection target is moving based on the detection step and distance, and a blur correction optical system And a step of controlling driving based on the step of determining.

Claims (8)

A calculation unit that calculates the distance to the detection target using the time until the projected light is received by the light receiving unit;
A first detection unit for detecting whether a change operation for changing the detection target is performed;
A second detection unit for detecting a change in the distance calculated by the calculation unit;
A blur correction optical system that is driven based on the detection result of blur and transmits the projected light; and
A distance detection apparatus comprising: a control unit that controls driving of the blur correction optical system using the output of the first detection unit and the output of the second detection unit. The distance detection device according to claim 1,
When the first detection unit does not detect the change operation of the detection target and the second detection unit detects a change in the distance that is greater than a first threshold, the control unit A distance detection device that performs control so that the change operation of the detection target is easily detected. The distance detecting device according to claim 2,
The distance detection device in which the control unit is not controlled so that the first detection unit easily detects the change operation of the detection target when the first detection unit detects the change operation of the detection target. The distance detection device according to any one of claims 1 to 3,
When the first detection unit does not detect the change operation of the detection target and the second detection unit detects a change in the distance that is greater than a second threshold value, the control unit The range of the frequency of blur detected by the blur correction unit that detects the blur is detected when the change operation of the detection target is detected and the second detection unit detects the variation in the distance that is greater than the second threshold. A distance detection device that controls so as to be wide. The distance detection device according to any one of claims 1 to 4,
When the first detection unit does not detect the change operation of the detection target and the second detection unit detects a change in the distance that is greater than a second threshold value, the control unit A distance that weakens the control to bring the blur correction optical system closer to a predetermined position than when the change operation of the detection target is detected and the second detection unit detects a change in the distance greater than the second threshold. Detection device. The distance detection device according to any one of claims 1 to 5,
When the first detection unit does not detect the change operation of the detection target and the second detection unit detects a change in the distance that is greater than a second threshold value, the control unit Control is performed so that the range in which the blur correction optical system is driven is wider than when the change operation of the detection target is detected and the second detection unit detects a variation in the distance that is greater than the second threshold. A distance detection device. The distance detection device according to any one of claims 1 to 6,
The first detection unit detects a change operation of the detection target when a shake larger than a third threshold is generated, and detects a change operation of the detection target when a shake greater than the third threshold is not generated. Detection device.   An optical apparatus comprising the distance detection device according to any one of claims 1 to 6.

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