JP2007306436A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which acquires blurring speed and calculates exposure time according also to the acquired blurring speed. <P>SOLUTION: The imaging apparatus has a blurring speed acquisition part 0201 which acquires the blurring speed of a subject in an imaging area generated by handshaking and an exposure time calculation part 0202 which calculates the exposure time based also on the acquired blurring speed. Since it often becomes exposure shortage when the exposure time is short, the imaging apparatus is further provided with functions for collecting such a photographed image which becomes the exposure shortage by gain adjustment and aperture adjustment, etc. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for efficiently reducing and correcting an influence on an imaging result caused by camera shake.

  There is a problem that the sharpness of a photographed image is lowered due to so-called “camera shake” and the quality of the image is deteriorated, for example, when a person holds the image pickup device by hand. This problem has become more apparent with the widespread use of camera-equipped mobile terminals that can be easily imaged with one hand and the reduction in size and weight of digital cameras. In order to solve this “camera shake” problem, various image stabilization techniques such as “optical camera shake correction” and “electronic camera shake correction” have been developed and provided.

Also, “camera shake” is a phenomenon that occurs because the light of the subject blurs on the imaging area when the imaging apparatus shakes during exposure, and therefore the influence of camera shake increases with the length of the exposure time. Therefore, in Patent Document 1, an exposure time during which “blurring” can be ignored during photographing is calculated based on the photographing optical system, subject luminance information, and focal length information. However, since the appropriate amount of light for imaging cannot be obtained with the short exposure time (underexposure), combining multiple images taken continuously with the calculated exposure time eliminates blurring and provides the appropriate amount of light. A technique for performing imaging is disclosed.
JP 09-261526 A

  However, in the technique of the above-mentioned Patent Document 1, the exposure time that can ignore the “blur” is calculated without considering the blur speed. Therefore, when the blur speed is high, there is a problem that the fast blur may not be ignored even in the exposure time that should be able to ignore the calculated “blur”.

  In order to solve the above-described problems, the present invention provides an imaging apparatus that acquires a blur speed and calculates an exposure time according to the acquired blur speed. Specifically, an imaging apparatus having a blur speed acquisition unit that acquires a blur speed of a subject in an imaging area caused by camera shake, and an exposure time calculation unit that calculates an exposure time based on the acquired blur speed. is there.

  In addition, as described above, when the exposure time is short, the exposure is often underexposure. Therefore, the captured image with such underexposure is corrected for the imaging result using the gain value, or the image is opened before imaging. An imaging apparatus further provided with a function of adjusting the amount of incident light by adjusting the degree is also provided.

  According to the present invention having the above-described configuration, it is possible to perform shooting with an exposure time in consideration of the blur speed. Therefore, it is possible to set an exposure time that balances the influence of camera shake and exposure while suppressing the effect of camera shake speed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments, and can be implemented in various modes without departing from the spirit of the present invention.

  In the first embodiment, claims 1, 5, and 6 will be mainly described. In the second embodiment, claims 2 and 7 will be mainly described. In the third embodiment, claims 3 and 8 will be mainly described. In the fourth embodiment, claims 4 and 9 will be mainly described.

Example 1
<Overview>
FIG. 1 is a diagram showing a part of an imaging sensor surface (imaging area) composed of a photoelectric conversion element group such as a CCD or a CMOS. An example of imaging in the imaging apparatus of the present embodiment is shown in FIG. Will be explained. First, the shutter of the imaging device is opened and the imaging sensor surface is exposed. Then, as shown in FIG. 1A, light from the subject hits the photoelectric conversion element region α on the imaging sensor surface, and charges are accumulated. However, as shown in (2a) of this figure, when camera shake occurs at the “camera shake speed a” indicated by the arrow in the imaging apparatus that is being exposed in 0.5 seconds, the light that has hit the region α The surface of the image sensor is slid to the left in accordance with the movement, and charges are accumulated in the region up to the region β indicated by the diagonal lines. As a result, camera-captured captured image data is acquired in this imaging apparatus.

  On the other hand, as shown in this figure (2b), when the camera shake speed is twice as high as "b", the camera shake range is the same as the camera shake speed even with the same exposure time of 0.5 seconds as in the figure (2a). The amount increases by the amount of increase. Therefore, the image pickup apparatus of the present embodiment is characterized in that it has a function of calculating an exposure time that can ignore the shake according to the shake speed. For example, if the blur of (2a) in FIG. 1 is negligible, the exposure time is calculated as 0.5 seconds at this “shake speed a”. In the case of camera shake at “camera shake speed b” shown in (2b) of FIG. 1, the range of camera shake is twice that of (2a), so the exposure time is halved to 0.25 seconds. Condition.

<Functional configuration>
FIG. 2 is a diagram illustrating an example of functional blocks in the imaging apparatus of the present embodiment. As shown in this figure, the “imaging device” (0200) of the present embodiment includes a “blur speed acquisition unit” (0201) and an “exposure time calculation unit” (0202).

  Note that the functional blocks of the apparatus described below can be realized as hardware, software, or both hardware and software. Specifically, if a computer is used, a CPU, a main memory, a bus, or a secondary storage device (a storage medium such as a hard disk, a nonvolatile memory, a CD-ROM or a DVD-ROM, and a reading drive for these media) Etc.), hardware components such as printing devices, display devices, other external peripheral devices, I / O ports for the external peripheral devices, driver programs for controlling the hardware, other application programs, and information input Examples include user interfaces that are used. In addition, these hardware and software process the program developed on the main memory with the CPU, and process, store, and output data stored on the memory and hard disk, and data input via the interface. It is used for processing or controlling each hardware component. The present invention can be realized not only as an apparatus but also as a method. A part of the invention can be configured as software. Furthermore, a software product used for causing a computer to execute such software and a recording medium in which the product is fixed to a recording medium are naturally included in the technical scope of the present invention (the same applies throughout the present specification). Is).

  The “blur speed acquisition unit” (0202) has a function of acquiring the blur speed of the subject in the imaging area caused by the camera shake. “Imaging area” refers to an area for acquiring imaging data, which is composed of a group of photoelectric conversion elements such as a CCD and a CMOS.

  As an example of the method for acquiring the shake speed, first, the amount of movement or direction of the imaging apparatus in a predetermined time is detected using various sensors such as an angular velocity sensor, an acceleration sensor, and a gravity sensor provided in the imaging apparatus. . Even with the same amount of movement of the imaging device, the amount of blurring of the subject in the imaging area changes according to the focal length of the lens, the distance to the subject, the lens magnification, and the like. Therefore, based on the detected amount of movement of the imaging device, the focal length of the lens, the distance to the subject detected by an AF (autofocus) sensor, or the lens magnification, the blurring of the subject within the imaging area is determined. The speed is calculated and acquired.

  Alternatively, as will be described later, block matching is performed on two images continuously acquired before actual imaging to detect a motion vector, and the amount of movement of a subject in the captured image indicated by the motion vector is used to determine whether or not within the imaging area. A method of calculating and acquiring the blur speed of the subject is also included.

  The “exposure time calculation unit” (0202) has a function of calculating the exposure time based on the acquired blur speed. Specifically, the exposure time calculation unit is realized by an arithmetic unit such as a CPU or a main memory, for example. In addition to the blur speed, the subject luminance value of the imaging device, the size and resolution of the imaging element, the aperture size of the lens, and the like There is a method of calculating by using a predetermined mathematical formula having the numerical value of as a variable.

  FIG. 3 is a diagram for explaining an example of exposure time calculation in the exposure time calculation unit. As shown in this figure, the larger the numerical value of the camera shake speed “H”, the shorter the exposure time “T”. The predetermined function f (H) = T = a / H + k (a: arbitrary coefficient, k: arbitrary number) ) And the like are used to calculate the exposure time T. Further, a plurality of such functions are prepared according to the luminance of the subject, such as T = f1 (H), T = f2 (H), T = f3 (H),. You can use different functions to apply. Further, the exposure time calculated in this way is compared with the exposure time for normal appropriate exposure, or the average value of the plurality of exposure times is used as the exposure time calculated by the exposure time calculation unit. There may be.

Then, by performing imaging according to the exposure time calculated in this way, the imaging apparatus of the present embodiment can perform imaging with an exposure time corresponding to the camera shake speed. Therefore, it is possible to set an exposure time that balances the influence of camera shake and exposure while suppressing the effect of camera shake speed.
In addition, in the imaging apparatus of the present embodiment, the blur speed acquired by the blur speed acquiring unit is not noticeable by human eyes before calculating the exposure time at which the blur speed can be ignored by the exposure time calculating unit. It is also possible to perform a determination process using a threshold or the like. In this case, the threshold value may be set according to the pixel size, the resolution of the imaging area, and the like.

    It should be noted that the occurrence of such blur is light in the imaging apparatus as described above, and is likely to occur in a portable information terminal with a camera held with one hand. Therefore, an imaging device having such a blur correction function may be incorporated in the portable information terminal.

<Hardware configuration>
FIG. 4 is a schematic diagram illustrating an example of the configuration of the imaging apparatus when the above functional components are realized as hardware. The operation of each hardware component in the exposure time calculation process will be described using this figure. As shown in this figure, the imaging apparatus is an exposure time calculation unit and a camera shake speed acquisition unit “CPU (central processing unit)” (0401), “main memory” (0402), and “angular velocity sensor”. (0403). In addition, “EEPROM” (0404) holding various programs and setting information, “shutter opening / closing mechanism” (0405) for controlling the opening / closing of the shutter according to the calculated exposure time, obtained by the CCD. “I / O (input / output)” (0406) to which the captured image data is input, and “frame memory” (0407) for storing the input image data. Of course, an imaging mechanism such as a “shutter”, “lens”, and “CCD” is also provided. Then, they are connected to each other by a data communication path such as a “system bus” to transmit / receive information and process information.

  In addition, the “main memory” provides a work area that is also a work area for the program at the same time it is read to execute the program held in the “EEPROM”. In addition, a plurality of addresses are assigned to each of the “main memory”, “EEOROM”, “frame memory”, etc., and programs executed by the “CPU” specify each other to access each other. Data can be exchanged and processed.

Here, for example, when a “shutter button” (not shown) is pressed halfway, the imaging apparatus of the present embodiment follows the “exposure time calculation program” read from the “EEPROM” to the work area of the “main memory”. Then, an exposure time suitable for the photographing is calculated. For this purpose, first, the “angular velocity sensor” detects the movement amount and direction of the imaging apparatus as the movement information, and stores it in the address 1 of the “main memory”. Further, the distance to the subject measured by an “autofocus distance measuring sensor” (not shown) or the like is stored in address 2 of “main memory”, and current magnification setting information is stored in address 3. Then, “movement blur of the subject within the imaging area” is calculated, for example, “shift by 5 pixels in 0.1 seconds” from the movement information of the imaging device, the distance to the subject, and the lens magnification. Etc. are calculated.
Then, the shake speed calculated in this way is compared with the visually acceptable shake range (threshold value) previously stored in the “EEPROM” by the size comparison process of the “CPU”. As a result, if the blurring speed is equal to or less than a threshold value indicating a level that is not noticeable to the eyes of a general person, an exposure time that makes a normal exposure amount appropriate is calculated.
On the other hand, when the blur speed is equal to or higher than the threshold value, the exposure time at which the blur can be ignored is calculated by the calculation process of the “CPU” using the function T = f (H) as described above, and the first exposure The time is stored in address 4 of the “main memory”.

  Further, the luminance value of the subject acquired in the imaging area is stored in the address 5 of the “main memory”, and the exposure time for which the exposure amount is appropriate is calculated from the luminance value by the arithmetic processing of the CPU. Then, the exposure time at which the exposure amount is appropriate is stored in the address 6 of the “main memory” as the second exposure time.

  Then, by comparing the size of the first and second exposure times by the “CPU” size comparison process, if the first exposure time is shorter than the second exposure time, the “shutter opening / closing mechanism” By controlling the shutter opening / closing time at 1 as the first exposure time, image pickup without blurring is performed. When the first exposure time is longer than the second exposure time (exposure time with an appropriate exposure amount), the shutter opening / closing time in the “shutter opening / closing mechanism” is controlled as the second exposure time. To avoid overexposure. Alternatively, an average value of the first and second exposure times is taken, and shutter opening / closing control is performed with the average exposure time. Then, the image that is captured in such a manner as to balance camera shake and exposure is stored in the “frame memory”.

<Process flow>
FIG. 5 is a flowchart illustrating an example of a process flow in the imaging apparatus according to the present exemplary embodiment. Note that the steps shown below may be processing steps that constitute a program for controlling a computer recorded on a medium. As shown in this figure, first, the blur speed of the subject in the imaging area caused by camera shake is acquired (step S0501). Then, the exposure time is calculated based on the acquired blur speed and other information such as the focal length, the luminance information of the subject, and the distance to the subject (step S0502).
Further, as described above, the actual exposure time is calculated by using the exposure time calculated so that the blur can be ignored in step S0502 and the exposure time for obtaining an appropriate exposure amount calculated from, for example, luminance information. May be calculated. In that case, first, an exposure time at which the exposure amount is appropriate is calculated from the luminance information in the imaging area (step S0503). When α is input, for example, when the user inputs α or β selection information, the actual exposure time is obtained by comparing the exposure time calculated in step S0502 with the exposure time calculated in step S0503. Calculate (step S0504α). On the other hand, if β is input, the average value of the exposure time calculated in step S0502 and the exposure time calculated in step S0503 is calculated as the actual exposure time (step S0504β).

<Brief description of effect>
As described above, it is possible to perform imaging with an exposure time that also considers the blurring speed by the imaging apparatus of the present embodiment. Therefore, it is possible to set an exposure time that balances the influence of camera shake and exposure while suppressing the effect of camera shake speed.

<< Example 2 >>
<Overview>
The present embodiment is an image pickup apparatus based on the first embodiment and using a preview image when acquiring the shake speed.

  FIG. 6 is a conceptual diagram for explaining an outline example of acquisition of the shake speed using the preview image. As shown in FIG. 6 (a), the block α in the preview image A acquired immediately before the actual imaging is shown in FIG. 6 (b). Has moved to. In the imaging apparatus of the present embodiment, this movement is detected by block matching or the like, and a function of calculating a shake speed from the detected movement amount is provided.

<Functional configuration>
FIG. 7 is a diagram illustrating an example of functional blocks in the imaging apparatus of the present embodiment. As shown in this figure, the “imaging device” (0700) of the present embodiment has a “blur speed acquisition unit” (0701) and an “exposure time calculation unit” (0702) based on the first embodiment. . Since this “exposure time calculation unit” is the same as that described in the first embodiment, the description thereof is omitted. The “blur speed acquisition unit” is the same as that described in the first embodiment except for the feature points described below.

  A feature point of the image pickup apparatus of the present embodiment is that the shake speed acquisition unit further includes “preview shake speed acquisition means”.

The “preview blur speed acquisition means” (0703) has a function of acquiring a blur speed using a preview image. “Preview image” refers to an image acquired prior to actual imaging. For example, in addition to an image acquired separately for blur speed acquisition, an image acquired for a monitor screen or a hill-climbing auto For example, an image acquired for focusing. A plurality of such preview images stored in the “frame memory” are used, and a motion vector is detected locally by block matching, for example.
In block matching, for example, first, a matching search range in a second image for detecting a motion vector of a block in the first image is determined. For this purpose, a search range constituted by a predetermined group of blocks around the second image block at the same position as the first image block is determined. Then, a block closest to the subject image in the block of the first image is detected from the search range using pixel values and distribution information thereof. Then, a local motion vector having the movement amount as a horizontal and vertical component is detected. The motion vectors are similarly detected for the other detection blocks.
Then, the blurring amount of the subject in the imaging area is detected using the average value, median value, or maximum motion vector of the motion vectors of the entire imaging area thus detected, and the detected blurring amount and the preview For example, the blur speed is calculated by the arithmetic processing of the “CPU” from the image acquisition interval time, the pixel size, and the like.

<Process flow>
FIG. 8 is a flowchart illustrating an example of a processing flow in the imaging apparatus according to the present exemplary embodiment. Note that the steps shown below may be processing steps that constitute a program for controlling a computer recorded on a medium. As shown in this figure, first, a preview image is acquired (step S0801). Next, using the preview image, the blur speed of the subject in the imaging area caused by camera shake is acquired (step S0802). Then, the exposure time is calculated based on the acquired blur speed and other information such as focal length, subject luminance information, and distance to the subject (step S0803).

<Brief description of effect>
As described above, the imaging apparatus according to the present exemplary embodiment can acquire the blur speed for calculating the exposure time using the preview image. Since the preview image can be obtained by a “frame memory” or the like, a special member for obtaining the shake speed such as an angular velocity sensor is not required, and the apparatus configuration can be simplified.

Example 3
<Overview>
FIG. 9 is a conceptual diagram for explaining the feature points of the imaging apparatus according to the present embodiment. The imaging apparatus according to the present embodiment performs imaging with an exposure time in which blurring can be ignored based on the first and second embodiments in consideration of the blurring speed. However, since an image captured with such an exposure time is insufficient in exposure time, a sufficient amount of light cannot often be obtained as shown in FIG. Therefore, the imaging apparatus according to the present embodiment has a function of correcting an underexposure by performing an adjustment based on a gain value with respect to the image when the captured image is underexposed. .

<Functional configuration>
FIG. 10 is a diagram illustrating an example of functional blocks in the imaging apparatus of the present embodiment. As shown in this figure, the “imaging device” (1000) of the present embodiment has a “blur speed acquisition unit” (1001) and an “exposure time calculation unit” (1002) based on the first embodiment. . Although not shown, based on the second embodiment, the shake speed acquisition unit may include “preview shake speed acquisition means”. Since the “exposure time calculation unit”, “blur speed acquisition unit”, and “preview blur speed acquisition unit” are the same as those described in the first and second embodiments, the description thereof is omitted.

  The feature point of the image pickup apparatus of the present embodiment is that it further includes a “determination unit” (1003) and an “adjustment unit” (1004).

  The “determination unit” (1003) has a function of determining whether underexposure occurs based on the calculated exposure time. This determination of underexposure is performed by calculating an exposure time at which the exposure amount is appropriate using, for example, a photometric value in a TTL (Through the Lens) method, and the exposure time and the blur calculated by the exposure time calculation unit. And a method of judging by comparing the exposure time with which can be ignored.

  The “adjustment unit” (1004) has a function of performing gain adjustment on the imaging result to compensate for the underexposure when it is determined that the underexposure occurs. The calculation of the gain value used for gain adjustment in the adjustment unit is, for example, a known technique based on the exposure time calculated by the exposure time calculation unit, the size and focal length of the camera lens, the F (aperture) value of the lens, and the like. It is good to calculate using. The underexposure imaging result can be corrected by correcting the brightness value of the imaging data stored in the “frame memory” using the calculated gain value.

  Also, in this gain value adjustment, the degree of correction is adjusted such that the brightness is adjusted high at the center of the image and the brightness is adjusted low to suppress noise enhancement at the periphery by performing the following processing. (Shading level) may be adjusted.

  FIG. 11 is a diagram illustrating an example of a function for determining the correction degree according to the position of the pixel. As shown in this figure, shading functions m1, m2,... Are prepared in advance for each gain value m. Then, the position of the pixel to be corrected is calculated as, for example, the Euclidean distance or the 4-neighbor distance (length) from the center of the imaging area and the center of the lens, and the correction value (Shading level) is calculated from the gain value and the length value. Is determined. In this way, the luminance can be adjusted to be high at the center of the image, and the luminance can be adjusted to be low at the periphery to suppress noise enhancement.

<Hardware configuration>
FIG. 12 is a schematic diagram illustrating an example of a configuration of the imaging apparatus when the functional components described above are realized as hardware. Here, the hardware configuration for realizing the “determination unit” and “correction unit” and the processing thereof, which are characteristic points of the present embodiment, will be described, and the blur speed acquisition and exposure time calculation described in the first embodiment will be described. Description is omitted.

  As shown in this figure, the imaging apparatus includes a “CPU (central processing unit)” (1201) that is also a determination unit, a “main memory” (1202), and a “frame memory” (1207) that is an adjustment unit. An image adjustment circuit "(1208) is provided. In addition, as in the first embodiment, “EEPROM” (1204), “shutter opening / closing mechanism” (1205), “I / O” (1206), and “shutter”, “lens”, and “CCD” which are imaging mechanisms. And so on. Then, they are connected to each other by a data communication path such as a “system bus” to transmit / receive information and process information.

  Here, as described in the first embodiment, the imaging data is acquired at the exposure time calculated so that the blur can be ignored, and stored in the “frame memory”. Then, the gain adjustment program held in “EEPROM” is read out to the work area of “main memory”, and it is first determined whether or not the exposure is insufficient. For this purpose, the actual exposure time is stored at address 1 of the “main memory”, and the exposure time for proper exposure is stored at address 2. If the actual exposure time is shorter than the exposure time at which proper exposure is performed by the size comparison processing of the “CPU”, it is determined that the exposure is insufficient.

  If it is determined that the exposure is insufficient, for example, the camera lens size and focal length, which are camera-specific information stored in “EEPROM”, or the F (aperture) value at the time of actual shooting is “ The gain value for exposure adjustment is calculated by the calculation process of the “CPU” and stored in the address 3 of the “main memory”. Subsequently, an applied correction value for each pixel is calculated from the gain value using, for example, a shading level function as shown in FIG. Then, for example, gain adjustment processing for each pixel is executed on the imaging data stored in the “frame memory” by the processing of the “image adjustment circuit”, and underexposure correction is performed.

<Process flow>
FIG. 13 is a flowchart illustrating an example of a processing flow in the imaging apparatus according to the present exemplary embodiment. Note that the steps shown below may be processing steps that constitute a program for controlling a computer recorded on a medium. As shown in this figure, the blur speed of the subject in the imaging area caused by camera shake is acquired (step S1301). Subsequently, the exposure time is calculated based on the acquired blur speed and other information such as focal length, subject brightness information, and distance to the subject (step S1302).

  Next, it is determined whether or not underexposure occurs based on the calculated exposure time (step S1303). If it is determined that underexposure occurs, gain adjustment for compensating for underexposure is performed on the imaging result. (Step S1304). If the determination result indicates that underexposure does not occur, the correction process is not executed on the imaged data, and the process ends.

<Brief description of effect>
As described above, when the captured image is underexposed by the imaging apparatus according to the present embodiment, gain adjustment can be performed on the image to correct the underexposure.

Example 4
<Overview>
As in the third embodiment, the present embodiment is characterized in that it has a function of correcting underexposure of an imaging result that is shot with an exposure time in which blurring can be ignored. The difference from the underexposure correction in the third embodiment is that correction processing is performed on the captured image data in the third embodiment, whereas in this embodiment, the lens aperture is adjusted before imaging. By adjusting the degree of opening and increasing the actual amount of incident light, the shortage of exposure at the time of shooting is compensated.

<Functional configuration>
FIG. 14 is a diagram illustrating an example of functional blocks in the imaging apparatus of the present embodiment. As shown in this figure, the “imaging device” (1400) of the present embodiment has a “blur speed acquisition unit” (1401) and an “exposure time calculation unit” (1402) based on the first embodiment. . Although not shown, based on the second embodiment, the shake speed acquisition unit may include “preview shake speed acquisition means”. Since the “exposure time calculation unit”, “blur speed acquisition unit”, and “preview blur speed acquisition unit” are the same as those described in the first and second embodiments, the description thereof is omitted.

  The feature point of the image pickup apparatus of the present embodiment is that it further includes a “determination unit” (1403) and an “opening degree adjustment unit” (1404).

  The “determination unit” (1403) has a function of determining whether underexposure occurs based on the calculated exposure time. The function of the determination unit is the same as that of the “determination unit” described in the third embodiment, and thus description thereof is omitted.

  The “aperture adjustment unit” has a function of adjusting the aperture to compensate for the underexposure when it is determined that underexposure occurs. “Aperture” refers to the degree of the amount of light entering the imaging area, and includes, for example, a general lens F (aperture) value.

FIG. 15 is a diagram illustrating an example of an aperture table for determining the aperture according to the exposure time. As shown in this figure, when the exposure time is “0.1 second”, the aperture value as the aperture is “F2.8”, and when the exposure time is “0.2 second”, the aperture value is “ It is better to determine the aperture according to the exposure time, such as “F4”. Of course, in addition to using such an opening degree table, the opening degree may be determined using a predetermined function having exposure time, subject luminance information, and the like as variables.
In addition, the opening degree adjustment unit according to the present embodiment responds to the exposure time by using, for example, an opening degree table as illustrated in FIG. 15 regardless of the determination result of the determination unit or without determination processing. The opening degree determination process may be executed.

  In this way, by adjusting the aperture according to the exposure time before imaging, the amount of light incident on the imaging area can be increased, and insufficient exposure at the actual shooting time can be compensated.

<Processing flow 1>
FIG. 16 is a flowchart illustrating an example of a processing flow in the imaging apparatus of the present embodiment. Note that the steps shown below may be processing steps that constitute a program for controlling a computer recorded on a medium. As shown in this figure, the blur speed of the subject in the imaging area caused by camera shake is acquired (step S1601). Subsequently, the exposure time is calculated based on the acquired blur speed and other information such as focal length, subject luminance information, and distance to the subject (step S1602).

Next, it is determined whether underexposure occurs based on the calculated exposure time (step S1603). As a result, if it is determined that underexposure occurs, aperture adjustment is performed to compensate for underexposure (step S1604), and imaging is performed with the aperture. If the determination result indicates that underexposure does not occur, aperture adjustment is not performed in this process, and imaging is performed with an aperture specified by the user, for example.
<Processing flow 2> Further, as described above, in this embodiment, an aperture degree determination process corresponding to the exposure time is performed using an aperture degree table or the like without performing a process of determining whether or not underexposure occurs. May be executed.
FIG. 17 is a flowchart illustrating an example of a process flow when the determination process is not performed in the imaging apparatus according to the present exemplary embodiment. Note that the steps shown below may be processing steps that constitute a program for controlling a computer recorded on a medium. As shown in this figure, the blur speed of the subject in the imaging area caused by camera shake is acquired (step S1701). Subsequently, the exposure time is calculated based on the acquired blur speed and other information such as focal length, subject luminance information, and distance to the subject (step S1702). Then, according to the calculated exposure time, the aperture is adjusted by using, for example, an aperture table as shown in FIG. 15 (step S1703), and imaging with the aperture is performed.

<Brief description of effect>
As described above, the amount of incident light in the imaging area can be increased by adjusting the aperture according to the exposure time before imaging by the imaging apparatus of the present embodiment, and insufficient exposure at the actual shooting time point. Can be supplemented.

The figure showing a part of imaging sensor surface for demonstrating an example of the imaging in the imaging device of Example 1. FIG. FIG. 6 is a diagram illustrating an example of functional blocks in the imaging apparatus according to the first embodiment. FIG. 6 is a diagram for explaining an example of exposure time calculation in an exposure time calculation unit of the imaging apparatus according to the first embodiment. Schematic showing an example of a hardware configuration in the imaging apparatus according to the first embodiment. 7 is a flowchart illustrating an example of a process flow in the imaging apparatus according to the first embodiment. FIG. 6 is a conceptual diagram for explaining an outline example of blur speed acquisition using a preview image in the imaging apparatus according to the first embodiment. FIG. 6 is a diagram illustrating an example of functional blocks in the imaging apparatus according to the second embodiment. 7 is a flowchart illustrating an example of a process flow in the imaging apparatus according to the second embodiment. Conceptual diagram for explaining underexposure correction in the imaging apparatus according to the third embodiment. FIG. 10 is a diagram illustrating an example of functional blocks in the imaging apparatus according to the third embodiment. FIG. 10 is a diagram illustrating an example of a function used in the adjustment unit of the imaging apparatus according to the third embodiment. Schematic showing an example of the hardware constitutions in the imaging device of Example 3. 7 is a flowchart illustrating an example of a process flow in the imaging apparatus according to the third embodiment. FIG. 10 is a diagram illustrating an example of functional blocks in the imaging apparatus according to the fourth embodiment. FIG. 10 is a diagram illustrating an example of an aperture degree table used in the aperture degree adjustment unit of the imaging apparatus according to the fourth embodiment. 8 is a flowchart illustrating an example of a process flow in the imaging apparatus according to the fourth embodiment. 9 is a flowchart illustrating another example of the process flow in the imaging apparatus according to the fourth embodiment.

Explanation of symbols

0200 Imaging device 0201 Blur velocity acquisition unit 0202 Exposure time calculation unit

Claims (11)

A blur speed acquisition unit that acquires the blur speed of the subject in the imaging area caused by camera shake;
An exposure time calculation unit that calculates an exposure time based on the acquired blur speed;
An imaging apparatus having   The imaging apparatus according to claim 1, wherein the blur speed acquisition unit includes a preview blur speed acquisition unit that acquires a blur speed using a preview image. A determination unit for determining whether underexposure occurs based on the calculated exposure time;
An adjustment unit that applies gain adjustment to the imaging result to compensate for the underexposure when it is a determination result that underexposure occurs;
The imaging device according to claim 1, further comprising: A determination unit for determining whether underexposure occurs based on the calculated exposure time;
The imaging apparatus according to any one of claims 1 to 3, further comprising an aperture degree adjustment unit that performs an aperture degree adjustment that compensates for the underexposure when it is determined that insufficient exposure occurs.   The portable information terminal which has an imaging device as described in any one of Claim 1 to 4. A shake speed acquisition step of acquiring the shake speed of the subject in the imaging area caused by camera shake;
An exposure time calculating step of calculating an exposure time based also on the acquired blur speed;
An imaging method for causing a computer to execute. A preview blur speed acquisition step of acquiring a blur speed of the subject in the imaging area caused by camera shake using a preview image;
An exposure time calculating step of calculating an exposure time based also on the acquired blur speed;
An imaging method for causing a computer to execute. A shake speed acquisition step of acquiring the shake speed of the subject in the imaging area caused by camera shake;
An exposure time calculating step of calculating an exposure time based also on the acquired blur speed;
A determination step of determining whether underexposure occurs based on the calculated exposure time;
An adjustment step for applying gain adjustment to the imaging result to compensate for the underexposure when it is a determination result that underexposure occurs;
An imaging method for causing a computer to execute. A shake speed acquisition step of acquiring the shake speed of the subject in the imaging area caused by camera shake;
An exposure time calculating step of calculating an exposure time based also on the acquired blur speed;
A determination step of determining whether underexposure occurs based on the calculated exposure time;
An adjustment step for applying gain adjustment to the imaging result to compensate for the underexposure when it is a determination result that underexposure occurs;
An aperture adjustment step for adjusting the aperture to compensate for underexposure;
An imaging method for causing a computer to execute. The imaging program for making a computer perform the imaging method as described in any one of Claims 6-9.
  A recording medium storing the imaging program according to claim 10.

Images