JP3700099B2 - Thermographic apparatus and thermographic display method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermography apparatus and a thermography display method that detect infrared rays from a subject and display a temperature distribution on a display screen in color, and in particular correct an emissivity of a specific region in a temperature distribution image. The present invention relates to an improvement of a possible thermography apparatus and a display method of thermography .
[0002]
[Prior art]
In general, in a thermography device, infrared energy radiated from an object is detected depending on temperature, and the obtained temperature signal is sent as a luminance signal to a display device such as a CRT (cathode ray tube), so that the subject The temperature distribution image is obtained. That either斯, thermography device, the ε emissivity of the object for different by substance, usually not it is inevitable that the temperature error is generated is provided with emissivity correction circuit.
[0003]
In the above-described conventional emissivity correction circuit , infrared rays from a subject are captured through a camera, and the same for all one screen of a temperature distribution image displayed on the screen of a display device, for example, emissivity ε _o It was made to make corrections.
[0004]
However, if the entire screen is corrected with the same emissivity ε _o , if there is a region in the subject having an emissivity ε _a different from the emissivity ε _o , the temperature value obtained for that region for error occurs, thermography device in the correction of the emissivity of any region in the temperature distribution image in the row cormorants like is disclosed in Japanese Patent Laid-Open No. 3-2250.
[0005]
In the above publication, as shown in FIG. 5, the center temperature 25 and the temperature width 26 are displayed on the screen 24 of the display device 11 such as a CRT, and the temperature distribution image 27 and the frame 28 are designated by the area. Only the pixels included in the designated area are subjected to emissivity correction to display the color temperature.
[0006]
[Problems to be solved by the invention]
The conventional thermography apparatus disclosed in the above-mentioned publication takes in the temperature data detected by the infrared detector into the image memory, and the correction data subjected to the emissivity correction by the emissivity correction circuit is again stored in the image memory using the correction data writing circuit. The frame setting circuit, frame writing circuit, frame display memory, etc. that specify the area are required for processing to write and read in the area specified by the frame, the circuit becomes complicated, and many circuit parts are required, There is a problem that the emissivity ε _o in the frame subjected to the emissivity correction cannot be directly viewed as to what value.
[0007]
The present invention is intended to provide a thermography device and a thermography display method that solve the above-mentioned problems, and the problem to be solved by the invention is not used for frame setting and the like, and is often used for a display device of a normal thermography device. The digital temperature display of the color temperature distribution image is displayed by digitally displaying the emissivity set at the designated point and the temperature value corrected by the emissivity in the vicinity of the designated point display (for example, the cross cursor) in the image being made. The emissivity set in the corrected part and the temperature value corrected for emissivity are understood immediately.
[0008]
[Means for Solving the Problems]
As shown in FIG. 1, the thermography apparatus and thermography display method of the present invention is based on temperature data obtained by detecting infrared energy from a subject, and corrects the emissivity of the entire screen to correct the temperature distribution of the subject. In a thermographic device that displays an image, a point that you want to know the temperature value in the image of the temperature distribution is specified, and the specified point is displayed near the specified point display (for example, a cross cursor) that shows the position of that point. The emissivity value set in (2) and the temperature value corrected by the emissivity are digitally displayed.
[0009]
According to the thermography display method of the present invention, emissivity correction can be performed in real time or in a frozen state, and the emissivity at the position where the corrected emissivity is set and the temperature value corrected with the emissivity are displayed on the screen. or thermography and thermographic methods very understand easily display method it is not necessary to correspond to obtain a.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the thermography apparatus and thermography display method of the present invention will be described in detail with reference to FIGS.
[0011]
FIG. 1 is a system diagram of the thermographic apparatus of the present invention, FIG. 2 is an external view of the main body excluding the camera unit, FIG. 3 is a screen example of the present invention, and FIG. 4 is an operation flowchart. Infrared rays emitted from the subject 1 in FIG. 1 are focused on an infrared detector 3 by an optical scanner 2 that performs raster scanning via a window 2a, and infrared detection is performed. The detector 3 has a chopper and a standard black body for guiding a reference infrared ray into the detector 3 every horizontal scanning of the optical scanner 2, and the reflected light from the standard black body is detected by the detector 3 when the chopper is disconnected. The output signal of the detector 3 is output as an AC signal proportional to the energy difference between the incident infrared ray and the standard black body.
[0012]
Such a weak AC signal is amplified by an operational amplifier (AMP) 4, detected by a signal synchronized with a chopper, averaged through a low-pass filtering circuit, etc., and an analog output signal is converted into an analog-digital conversion circuit (A / A). D) After being supplied to 5 and converted into digital data, it is supplied to the entire screen emissivity correction circuit 6 for correcting the emissivity ε _o of the entire screen. The entire screen emissivity correction circuit 6 is contained in a processing circuit including an absolute temperature regenerating unit and a linearizer, and image data is converted into a temperature signal corresponding to the absolute temperature. Further, the entire screen emissivity setting circuit 42 is configured to perform the overall correction of the entire screen emissivity correction circuit 6 by operating the entire screen emissivity setting key 43.
[0013]
The emissivity of a substance or an object varies depending on the environmental temperature of the substance and the difference between the substance or the object and has a value of 0.01 to 1. For example, in the surface where only aluminum was used, values of 0.04 to 0.06 at 50 ° C. to 100 ° C. and values of 0.94 to 0.91 at 20 ° C. to 100 ° C. are shown for glass. Usually, the entire screen emissivity correction circuit 6 often selects emissivity ε _o = 1.
[0014]
The output temperature data of the entire screen emissivity correction circuit 6 is sent to the image memory 9 via the switching means 8 and stored in the image memory 9. The emissivity correction in the frozen state can be performed in real time when the switching means 8 is on, and based on data stored in the image memory 9 described later when the switching means 8 is off. The switching means 8 is controlled by a data capture control circuit 7 constituted by a microcomputer (hereinafter referred to as CPU).
[0015]
The image memory 9 has a memory capacity of less that Kutomo one frame is rewritten for each frame scan.
[0016]
The temperature data stored in the image memory 9 and corrected with the same emissivity on the entire screen is read out via a reading circuit and a writing circuit (not shown) included in the CPU 7, such as a CRT for monitoring. The pixel data stored in the display memory 10 is stored within the gradation of the display device 11, and the pixel data stored in the display memory 10 is sent to the display device 11 through a display drive circuit or the like, and the temperature is displayed on the screen 24 of the display device 11. A distribution image 27 (see FIG. 3) and the like are displayed.
[0017]
In FIG. 1, an image memory point setting circuit 12 is a setting circuit including an operation unit for setting an index (hereinafter referred to as a cross cursor) 30 on the screen 24 of the display device 11 as shown in FIG. In the same manner, each circuit indicated by the reference numerals below the A / D conversion circuit 5 is arranged in the casing 32 of the main body 31 of the thermography device 20 and provided on the panel 33. The cross cursor 30 can be moved to an appropriate position on the screen 24 of the display device 11 by the index movement key 34.
[0018]
When the position specification of the cross cursor 30 is performed by the index movement key 34, the designated position is converted through the address decoder 13 to a predetermined address of the image memory 9, address cross cursor 30 position is stored in the image memory 9 The
[0019]
The calibration circuit 14 includes a calibration key 36 on the panel 33 and is a measurement circuit that corrects reflection due to the ambient temperature of the subject 1. Calibration data (CAL data) 15 measured by the calibration circuit 14 is an entire image emissivity correction circuit. 6 and the subtracter 17 and the adder 19.
[0020]
Based on the CAL data 15, the emissivity is corrected by the emissivity ε _o of the entire screen emissivity correction circuit 6.
[0021]
Furthermore, incorporating the position 置画 image data of the cross cursor 30 that is set in the image memory point setting circuit 12 to the buffer memory 16 is supplied to the subtracter 17, CAL data 15 and the entire screen emissivity correction measured in the calibration circuit 14 Subtraction of the data of the emissivity ε _o corrected by the circuit 6 is performed.
[0022]
The subtraction data subtracted by the subtracter 17 is supplied to the multiplier 18 at the next stage. The subtracted output data from the multiplier 18 is multiplied by the corrected emissivity data 22 set by the corrected emissivity setting circuit 23.
[0023]
When the emissivity setting key 37 of the corrected emissivity setting circuit 23 is pressed, the numeric keypad 39 and the like are displayed on the screen 24 of the display device 11 as shown in FIG. The emissivity ε _b may be specified.
[0024]
The multiplication data of the multiplier 18 is supplied to the adder 19 and added to the CAL data 15. The addition data of the adder 19 is supplied to the temperature value and emissivity value display circuit 21 and supplied to the CRT of the display device 11. The
[0025]
On the screen 24 of the CRT or the like of the display device 11, the correction emissivity setting circuit 23 is set at the position of the cross cursor 30 moved by the index movement key 34 of the image memory point setting circuit 12 as shown in FIG. The emissivity peculiar to the object, for example, the true emissivity and emissivity-corrected temperature value of the day-lit and shaded window glass in the color temperature distribution image 27 of the building of FIG. Is displayed as a digital display value 40 in the vicinity of the cross cursor 30.
[0026]
Therefore, the observer of the temperature distribution image 27 can immediately visually recognize the corrected temperature and the corrected emissivity in the image.
[0027]
In the above-described system diagram of FIG. 1, the subtracter 16, multiplier 18, adder 19, and the like are shown in hardware configuration, but can be processed by software by the CPU 7 constituting the data capture control circuit 7. .
[0028]
When processing is performed by the CPU 7, for example, the emissivity ε of the subject 1 is corrected by the entire screen emissivity correction circuit 6 in FIG. 1 is ε _o, and the true temperature of the subject 1 is f (T _o ). , when the environmental temperature is reflected from the object 1 and f (T _a), reflected by the surrounding environmental temperature f (T _a) of the object is represented by (1-ε) × f ( T a). Therefore, the temperature data of the image taken into the image memory 9 is expressed by the equation (1).
(Ε / ε _o ) × f (T _o ) + (1−ε / ε _o ) × f (T _a )
= (Ε / ε _o ) × {f (T _o ) −f (T _a )} + f (T _a ) (1)
Here, f (T _a ) is the CAL data 15 in FIG. 1, and the corrected emissivity in the corrected emissivity setting circuit 23 is ε _a, and (1) is converted to (2),
(Ε _o / Ε _a ) × (ε / ε _o ) × {f (T _o ) −f (T _a )} + f (T _a )
= (Ε / ε _a ) × {(T _o ) −f (T _a )} + f (T _a ) (2)
It is represented by
Here, if ε = ε _a , Equation (2) becomes {f (T _o ) −f (T _a )} + f (T _a ), and the true temperature f (T _a ) of the subject 1 is obtained.
[0029]
Therefore, the CPU 7 may be configured to perform the above equation as shown in FIG.
[0030]
That is, in the first step ST ₁ in FIG. 4, the temperature data (ε / ε _o ) × {f (T _{o of} subject 1) from the buffer memory 16. ) −f (T _a )} + f (T _a ) is taken into the memory of the CPU 7.
[0031]
In the second step ST ₂ , the true temperature f (T _a ) of the subject in the CAL data 15 is taken from the calibration circuit 14 into the memory of the CPU 7.
[0032]
In the third step ST ₃ , the corrected emissivities ε _a and ε _o are taken into the memory of the CPU 7 from the corrected emissivity setting circuit 23 and the entire screen emissivity setting circuit 42.
[0033]
In the fourth step ST ₄ , [(ε / ε _o ) × {f (T _o ) −f (T _a )} + f (T _a )] − f (T _a ) is subtracted, and in the fifth step ST ₅ (Ε _o / Ε _a ) × [(ε / ε _o ) × {f (T _o ) −f (T _a )}] is performed, and [(ε / ε _a ) × {f (T _o ) −f (T _a )}] in the sixth step ST _6. + f (T _a) by enabling emissivity correction by performing the addition of CAL data, the temperature T _o is corrected with emissivity epsilon _a correction emissivity set in the cross cursor 30 near on the CRT screen 24 Displayed as a digital display value.
[0034]
The multi-point position designation with the cross cursor 30 on the screen of the present invention is conventionally displayed in the vicinity of the cross cursor position as A, B, C..., And the reference scale for each temperature color displayed on the right end of the screen. Since it was displayed as A, B, C, etc. at position 41, it took time to find the corresponding temperature position on the screen 24. In this example, even when a multi-point position is specified. , a temperature value T _o of performing a respective set correction emissivity epsilon _a correction in correction emissivity to the position of the plurality of cross cursor 30 is at a temperature color reference scale 41 since it is digitally displayed, B, C ‥ It is possible to obtain a thermography device that does not need to visually match the symbols such as.
[0035]
【The invention's effect】
According to the thermography apparatus of the present invention, even when there is an object with different emissivity on the subject 1, there is no need to change the emissivity each time, and the emissivity can be determined only by specifying an index point such as a cross cursor. Since the correction can be performed, the emissivity difference based on the material difference of the object or the ambient temperature difference can be corrected, and since the correct temperature distribution of the corrected emissivity point is digitally displayed, an extremely easy-to-understand thermography apparatus can be obtained.
[Brief description of the drawings]
FIG. 1 is a system diagram of a thermography apparatus of the present invention.
FIG. 2 is an external view of a main body portion of the thermographic apparatus of the present invention.
FIG. 3 is a screen display explanatory diagram of the display device of the thermographic device of the present invention.
FIG. 4 is a flowchart of calculation of corrected emissivity according to the present invention.
FIG. 5 is an explanatory diagram of a screen of a conventional thermography apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Subject 3 Detection part 6 Whole screen emissivity correction circuit 9 Image memory 11 Display apparatus 17 Subtractor 18 Multiplier 19 Adder 20 Thermography apparatus 23 Correction emissivity setting circuit

Claims (4)

In a thermography device that displays a temperature distribution image of a subject by correcting the emissivity of the entire screen based on temperature data obtained by detecting infrared energy from the subject.
Specify the point you want to know the temperature value in the image of the temperature distribution , near the specified point display showing the position of the point, the emissivity value set at the specified point and the temperature corrected with that emissivity A thermographic apparatus characterized by digitally displaying values . 2. The thermographic apparatus according to claim 1, wherein the designated point is displayed in a multipoint position in the temperature distribution image . In the thermography display method, which displays the temperature distribution image of the subject by correcting the emissivity of the entire screen based on the temperature data detected from the infrared energy from the subject.
Specify the point you want to know the temperature value in the image of the temperature distribution , near the specified point display showing the position of the point, the emissivity value set at the specified point and the temperature corrected with that emissivity A thermographic display method characterized by comprising digitally displaying values . 2. The thermographic apparatus according to claim 1, wherein the designated point is displayed in a multipoint position in the temperature distribution image .

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