JPH02221825A - System for measuring spot temperature for thermographic device - Google Patents

Abstract

PURPOSE:To accurately grasp the change of temperature even if the temperature changes suddenly in a short time and to optionally adjust the revolving speed of a chopper by fixing a scanning mirror and measuring the spot temperature on the desired position of an object. CONSTITUTION:When an operator instructs surface scanning with the aid of an input means 6, a falsely colored thermo-image, for example, is displayed on a display device 4. Then, the operator instructs the position of the spot which should be observed with the aid of the means 6 while viewing the displayed image. When the operator instructs the position in a display screen, a control means 5 incorporates the address of the position and calculates what position a scanning means 1 should be fixed on. The operator instructs the start of measurement and the means 5 fixes the means 1 on the instructed position through a signal line 7. During this period, the image of an infrared detector 2 is kept being formed on the desired position of the object, so that the temperature on the position is consecutively measured. Furthermore, since the revolving cycle of the chopper can be optionally set, interference does not occur in the case of measuring the temperature.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a thermography device, and particularly to a thermography device that is capable of continuously measuring the temperature of a desired position (hereinafter referred to as a spot) of a subject. The present invention relates to a spot temperature measurement method in a thermography device.

[Prior Art] A device that measures the temperature distribution of a subject by scanning and detecting infrared rays emitted from the subject in two dimensions horizontally and vertically is widely known as a thermography device, and its schematic configuration is shown in Figure 4. Shown below.

What is shown in FIG. 4 is an example of a thermography device previously proposed by the applicant in which horizontal scanning and vertical scanning are performed using dedicated scanning mirrors. First, it is vertically scanned by a vertical scanning mirror (not shown) and then horizontally scanned by a horizontal scanning mirror 33.

The two-dimensionally scanned infrared rays are imaged in the vicinity of a hole formed in the center of the horizontal scanning mirror 33 by a condenser mirror 35 made of a concave mirror, and the luminous flux is further restricted by an aperture 36. The light reaches an infrared detector 38 via a relay lens 37.

Now, in a thermography apparatus, it is necessary to indicate the absolute temperature of the subject. To this end, in FIG. 4, a 1"7 chip 46 is disposed between the horizontal scanning mirror 33 and the aperture 36 so as to cross the optical axis 40, and a reference black body temperature source for absolute temperature indication ( (hereinafter referred to as reference) 47 is installed.
has a notch in a part and is formed with a mirror surface at least on the side facing the infrared detector 38, and is rotated at a constant rotational speed in synchronization with the period of object scanning by a motor or the like (not shown). There is. In other words, the infrared rays emitted from this reference temperature source 47 are
The infrared light is reflected by the mirror surface and reaches the infrared detector 38.

Next, a signal detected by the infrared detector 38 will be explained using FIG. 5. That is, the dust flap 46 is rotated in synchronization with the scanning period of the subject so that the cutout part of the chopper 46 is positioned on the optical axis 40 when infrared light from the subject is input, and at other times it is positioned on the optical axis 40. 40
By rotating the infrared detector 38 so as to cut off the reference temperature signal and the thermo signal from the subject, the infrared detector 38 detects a signal in which a reference temperature signal and a thermo signal from the subject appear alternately, as shown in FIG.

Next, the absolute temperature correction method will be explained using FIG. The signal detected by the infrared detector 38 is input to a pulse clamp circuit 48, and is pulse clamped by a pulse clamp signal generated in synchronization with the reference temperature signal shown in FIG. The output signal of this pulse clamp circuit 48 is input to an adder 49, and a reference equivalent voltage corresponding to the reference temperature is added thereto to obtain an absolute temperature-corrected output signal.

The signal subjected to absolute value temperature correction in this manner is subjected to well-known processing such as amplification, A/D conversion, and pseudo colorization in a subsequent signal processing circuit (not shown). and,
The measurement results are displayed on a display means such as a color CRT display or stored in a predetermined file as necessary.

With the above configuration, it is possible to accurately measure the temperature distribution in a desired range of the object. [Problem to be solved by the invention] Now, when measuring the temperature change of the object, one operator must determine the specific point of interest. There are times when it is desired to observe temperature changes continuously, but conventional thermography devices only scan the surface of the subject. Diagram (a)
As shown in , a plurality of thermo images #1. are sequentially obtained by surface scanning. #2. #3. #4.・
Temperature data A++ of spot A of interest from ...
It was necessary to extract Aa+ Aa+ A4+ . . . and display it graphically using an XY plotter or the like as shown in FIG.

However, the period T at which a thermoimage is obtained is 1/30 sec even in a telegene scan, and in some cases it takes about 4 sec in a slow one. Therefore, it has been impossible to track changes in temperature that show rapid changes in a short period of time.

The present invention is intended to solve the above-mentioned problems, and to provide a spot temperature measurement method for a thermography apparatus that can continuously measure the spot temperature of a subject in a thermography apparatus that performs surface scanning as shown in FIG. This is the purpose.

[Means for Solving the Problems] In order to achieve the above object, the spot temperature measurement method in the thermography apparatus of the present invention includes a scanning means that performs horizontal scanning and vertical scanning, a reference temperature source, and the reference temperature source. In the thermography apparatus, the thermography apparatus is equipped with a chopper that guides infrared rays emitted from the infrared rays to an infrared detector at a predetermined cycle, in which the scanning of the scanning means is stopped at a desired position, and the cycle of the chopper can be arbitrarily set. Accordingly, the spot temperature at a desired position of the subject is continuously measured.

[Operation] Since the present invention measures the spot temperature at a desired position of the subject by fixing the scanning mirror, it is possible to accurately grasp the temperature change even when the temperature shows a rapid change in a short period of time. Furthermore, since the number of revolutions of the choppers can be adjusted arbitrarily when measuring the spot temperature, the presence of the chopper does not cause any interference.

[Example] Examples will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of a spot temperature measurement method in a thermography apparatus according to the present invention. In the figure, 1 is a scanning means, 2 is an infrared detector, 3 is a signal processing circuit, 4 is a display device, and 5 6 represents a control means, 6 represents an input means, and 7.8 represents a signal line.

The scanning means 1 is for scanning the object surface, and has the same structure as shown in FIG. 4.

The signal processing circuit 3 performs the absolute temperature correction described in FIG. 6, amplification, A/D conversion, and well-known pseudo coloring processing using, for example, an LUT (look-up table).

As the display device 4, it is preferable to use a color CRT display.

The control means 5 controls the scanning means 1 via signal lines 7 and 8.
and outputs a control signal for spot temperature measurement to the signal processing circuit 3.

The input means 6 consists of a keyboard, a mouse, a light rail, etc., and is used to input the position of the spot to be measured, the sampling period of the signal, and the like.

The operation shown in FIG. 1 will be explained below while following the scanning procedure.

First, the operator instructs surface scanning using the input means 6. As a result, the thermography apparatus performs normal operation, and the display device 4 displays, for example, a pseudo-color thermographic image. Here, the operator uses the input means 6 to indicate the spot position of interest while looking at the displayed image. Note that since the shape of the subject may not be accurately grasped in thermoimages, it is preferable to use visible images in a thermography apparatus that can obtain visible images without parallax.

In this regard, in the configuration shown in FIG. 4, it is very convenient to arrange a visible light detector at the position where the image is formed by the condensing mirror 35, since it is possible to obtain a visible image without larax.

Now, for example, if the operator selects Figure 3 (a) on the display screen,
), the control means 5 will:
The address of the spot position is taken in and the position at which the scanning means 1 should be fixed is calculated.

Then, when the operator instructs to start measurement,
The control means 5 fixes the scanning means 1 at a designated position via a signal line 7. As a result, the spot image of the infrared detector 2 continues to be focused on the desired position of the subject, so the temperature at that position of the subject can be continuously measured.
On the other hand, since the chopper 4B (FIG. 4) still rotates at the predetermined scanning period, thermo data cannot be obtained periodically, which poses a problem in continuously measuring spot temperatures.

Therefore, in the present invention, the rotation period of the chopper 46 can be arbitrarily set so as not to interfere with spot temperature measurement. In other words, if the temperature change at the spot is predicted to be slow, the measurement time will be longer.
Therefore, since the sampling period of the thermo signal, which will be described later, may be relatively long, the rotation period of the chopper 48 can be set to be relatively long. Hachi 8 Tsuba 46
Even if the rotation period of is relatively short, it does not pose a problem for measurement. The rotation period of the chopper 46 can be automatically set by the side leg 1 means 5.

In this way, the temperature of a desired spot can be continuously measured while periodically referring to the reference temperature source.

The output of the infrared detector 2 is sampled in a signal processing circuit 3 after being subjected to absolute temperature correction as in the conventional case, digitized, and stored in a predetermined file. Note that the number of bits used for digitization is arbitrary;
Since the dynamic range of temperature is wide, it is desirable to use 16 bits or more. Furthermore, the sampling period can be selected as appropriate, but in order to accurately grasp the temperature change of the spot when the measurement results are displayed on the display device 4, Display device 4-1 to display the number of spot temperature samples.
It is best to make it the same as the number of pixels in the line. The situation is shown in the second
As shown in the figure.

Figure 2(a) shows the situation when the rotation period of the chopper 46 is set to a relatively long time T+, in which the reference temperature source is referenced during the period A in the figure, and the spot temperature is measured during the remaining time. be exposed. The sampling at this time is shown in the figure (
It is carried out at the timing shown in b). Now, if the number of pixels in one line of display device 1!4 is 512, then T
During the + period, 512 sampling pulses are generated. Moreover, FIG. 2(C) shows the situation when the rotation period of the chopper 46 is set to a relatively short time Tt, and the reference time B of the reference temperature source at this time is as shown in FIG. 2(a).
The time is shorter than the time indicated by A in . Also, the number of sampling pulses generated during T years is 512, but compared to FIG. 2(b), the sampling period is shorter because the rotation period of the chopper 46 is shorter. It is. Note that the sampling frequency is automatically set by the control means 5 according to the rotation period of the chopper.

The thermo data stored in the file in this way is
The images are read out and displayed in the order in which they are captured in synchronization with the scanning of the display device 14. Therefore, when the number of pixels in one scanning line of the display device 4 is 512, the first scanning line of the display device 4 contains the first 512 pieces of thermodata acquired during the first rotation of the chopper 46. The obtained thermo data are displayed in that order, and the 512 thermo data obtained during the next rotation period are displayed on the second scanning line in the order in which they were captured.

As for the display method, brightness modulation may be performed as is based on the read thermodata, or known pseudo-coloring may be performed by assigning a predetermined color depending on the temperature. Now, for example, if we display in pseudo color, if the entire surface of the display device 4 is displayed in the same color, we can see that there is no temperature change at all, and if there is some kind of color change, the set chopper From the rotation period of the , it is possible to recognize what kind of temperature change occurred over what time.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, only one spot is designated, but a plurality of spots may be designated as shown in FIG. 3(b).

In this case, the control means 5 takes in the address of each spot position, and after first measuring the temperature of the reference temperature source, for example, A, B, C.

The temperature of each spot is sequentially measured in the order B, C, . . . , and the measured thermo data is stored in separate files.

Furthermore, the scanning means is not limited to the one shown in FIG.
As long as the reference temperature source is referred to by a chopper, other methods can be applied. [Effects of the Invention] As is clear from the above description, according to the present invention, one thermography apparatus can Both scanning temperature measurement and continuous spot temperature measurement can be performed, which is very convenient. Furthermore, since the rotation period of the chopper can be set arbitrarily, the chopper does not interfere with spot temperature measurement.

Further, in the present invention, since the reference temperature source is periodically referred to, even if a drift occurs in the thermography apparatus, the influence thereof can be canceled out periodically, and the absolute temperature can be accurately indicated.

Furthermore, by displaying the thermo data on a color CRT display or the like, it is possible to accurately grasp the state of temperature change.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of one embodiment of a spot temperature measurement method in a thermography apparatus according to the present invention, FIG. 2 is a diagram showing the relationship between the rotation period of the chopper and the sampling period of thermo data, and FIG. 3 is a diagram showing the spot temperature measurement method according to the present invention. Diagram showing location, 4th
The figure shows the scanning system of the thermography apparatus previously proposed by the applicant, Fig. 5 schematically shows the waveform of the signal generated from the infrared detector, and Fig. 6 shows the conventional method. FIG. 7 is a diagram illustrating absolute temperature correction, and FIG. 7 is a diagram illustrating conventional spot temperature measurement. DESCRIPTION OF SYMBOLS 1... Scanning means, 2... Infrared detector, 3... Signal processing circuit, 4... Display device, 5... Control means, 6
...Input means, 7.8...Signal line. Applicant JEOL Co., Ltd. Agent Patent attorney Hideo Sugai (5 others) (a) (b) Renos 11-Shikigu L (l

Claims (1)

[Claims] (1) In a thermography apparatus comprising a scanning means for performing horizontal scanning and vertical scanning, a reference temperature source, and a chopper that guides infrared rays emitted from the reference temperature source to an infrared detector at a predetermined period, the scanning means Spot temperature in a thermography apparatus, characterized in that the scanning of the chopper is stopped at a desired position, and the cycle of the chopper can be arbitrarily set, thereby continuously measuring the spot temperature at a desired position of a subject. Measurement method.