JP2830083B2 - Infrared imaging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared imaging device capable of displaying a two-dimensional temperature distribution on a screen or recording as image data by photographing an object to be measured. .

2. Description of the Related Art Every object emits infrared rays according to its temperature unless it is at absolute zero. Focusing on this, a technique of measuring the temperature of an object by measuring the amount of infrared rays emitted from the object has long been known. Infrared imaging devices that take a two-dimensional image of this and capture it as an image have already been widely used.

In this infrared image, a certain temperature range is displayed on the screen. At that time, the temperature range to be displayed (usually the lowest temperature level) and the width of the temperature range (how many times to how many times) ) Must be specified. Hereinafter, the former is called an offset level, and the latter is called a window.

Conventionally, the offset level has been adjusted so as to obtain an appropriate temperature distribution image while viewing the infrared image appearing on the screen. It is difficult to adjust to a certain level because the low temperature part is mixed. In particular, when trying to make the gradation of the infrared image the same between the previous observation and this observation, or when you want to display different DUTs on the same scale, just look at the infrared image and set the offset level. It is difficult to adjust to a constant.

Another inconvenient point when adjusting the offset level is that if the gain when converting the infrared intensity to the density of the image changes, the offset level moves too fast or too slow when adjusting the offset level. It takes time.

An object of the present invention is to solve such a problem and to provide an infrared imaging apparatus in which the offset level can be easily adjusted.

Means for Solving the Problems To achieve the above object, in the present invention, the object to be measured is 2
In an infrared imaging device that scans two-dimensionally and receives infrared light, and converts the intensity of the infrared light into image data that should be shaded on the screen, when converting infrared light to image data,
Means for changing an offset level defined as an infrared intensity to be converted to a predetermined reference density, such that the offset level is displayed on the screen simultaneously with the infrared image,
Means for adding offset display data to the image data, means for changing the gain at the time of conversion from infrared to image data, and means for changing the speed of changing the offset level according to the gain. According to the present invention, there is provided an infrared imaging apparatus for two-dimensionally scanning an object to be measured, receiving infrared light, and converting the intensity of the infrared light into image data to be shaded on a screen.
Means for changing an offset level defined as an infrared intensity to be converted to a predetermined reference density at the time of conversion from infrared to image data, such that the offset level is displayed simultaneously with the infrared image on a screen; Means for adding offset display data to the data, a key switch for outputting a signal corresponding to the amount of depression, and means for changing the speed of changing the offset level according to an output signal from the key switch. And

Function In the present infrared imaging apparatus, as shown in FIGS. 1 (a) to 1 (c), incident infrared light is converted into an electric signal within a predetermined range by a conversion means M1, and a two-dimensional image is generated by an image data generation means M2. Convert to data. Then, as shown in FIG. 1A, the offset level changing means M3 is connected to the converting means M1.
Is changed, the data adding means M4 adds data indicating the offset level to the image data.
Therefore, when this image data is sent to a display device (not shown), the offset level is displayed on the screen simultaneously with the infrared image, and the offset adjustment can be easily performed.

In the first embodiment, as shown in FIG. 1 (b), there is provided a means M5 for changing a gain at the time of conversion from infrared rays to an electric signal, and the changing speed changing means M6 is provided with a changing speed M6. Depending on the size, the offset level changing means
Change the offset change speed of M3. In the second mode, the offset changing speed changing means M8 changes the offset changing speed of the offset level changing means M3 not according to the gain but according to the amount of depression of the key switch M7 by the operator. In these cases, the speed of changing the offset level changes smoothly or arbitrarily according to the sense of the viewer, so that the offset adjustment becomes easy.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Appearance> As shown in FIG. 2, the present embodiment is a portable infrared imaging apparatus 10, and as shown in FIG.
By grasping and operating 12 with both hands, an infrared image of the object can be observed on site. The main body 14 of the device 10 is provided with a battery pack 16 as a power source and a CRT viewer 18 for observing an infrared image or the like on the spot, in addition to the movable grip 12 that protrudes to both sides at the lower part of the previous report. . As shown in the plan view of FIG. 3 (a) and the front view of FIG. 3 (b), the grip 12 is shaped so that it can be easily grasped by the left and right hands. And various switches are arranged. Details of these switches will be described later. Further, a side panel as shown in FIG. 4 is provided on a side surface (the side surface on the other side in FIG. 2) of the main body 14, and various switches are arranged in addition to the power switch 20 of the device 10. As described later, on this side panel, only switches that are operated first after the power is turned on are arranged, and at the time of normal observation, almost all switches can be operated only with the switches provided on the grip 12. It is designed to be. Accordingly, the operator can adjust the focusing and the offset of the infrared image screen and the window described later while holding the grip 12 and looking into the viewer 18.

<Principle of Imaging> The principle of imaging by the device 10 will be described with reference to FIG. The infrared light 22 emitted from the object is reflected by one surface of the polygon mirror 24, passes through a condenser lens 26, and is detected by an infrared detector 28. At this time, by rotating the polygon mirror 24, the imaging target surface 30 can be scanned horizontally. Further, a plurality of infrared detecting elements are arranged in the detector 28, and a range (band) having a certain width is obtained by rotating one surface (first surface, second surface,...) Of the polygon mirror 24 by a predetermined angle. Are scanned at once. Then, the mirrors around the polygon mirror 24 are inclined at a fixed angle to each other with respect to the rotation axis z, and the scanning bands (band 1, band 2,... Is arranged so as to cover without gaps, so that one image can be captured by one rotation of the polygon mirror 24.

The infrared detector 28 generates an electric signal corresponding to the intensity of the detected infrared light, and this electric signal is processed by the control circuit shown in FIG. 7A, and the CRT screen of the viewer 18 (FIG. 7A) Is displayed on the display device 49) as a grayscale image.
Alternatively, it is output as a video signal.

<Generation of Image Data> The signal output from the detector 28 in FIG. 7A is amplified by the preamplifier 31 and cut into high-frequency components by the low-pass filter 32 before being input to the offset injection circuit 33.
The offset injection circuit 33 arbitrarily changes the reference level (offset level) of the signal from the low-pass filter 32 by injecting the signal from the D / A converter 34 into the signal from the low-pass filter 32, as described later. It is to let.

The output signal from the offset injection circuit 33 is input to the multiplexer 35, and a number of signals corresponding to the number of detection elements of the multi-element infrared detector 28 are multiplexed (multiplexed) here. The multiplexed signal is amplified by an amplifier 36, digitized by an A / D converter 37, and stored in an image memory (RA
M) led to 38.

On the other hand, the polygon mirror 24 is rotated by the motor 25, and the rotation is monitored by the photo sensor 40, and the timing generation circuit 41 generates a timing pulse based on the detection signal. This timing pulse is applied to the input address counter 42
, And is output to the image memory 38 as an address signal corresponding to the rotation angle of the polygon mirror 24. Image memory 38
Stores the infrared intensity value from the A / D converter 37 at the address indicated by the input address counter 42. Thus, image data for one screen corresponding to one rotation of the polygon mirror 24 is stored in the image memory 38.

<Reading of Image Data> The image data stored in the image memory 38 is displayed on the CRT of the viewer 18 by a normal TV system. Therefore, first, a synchronizing signal is generated by the television synchronizing signal generator 44, and the address data of the image memory 38 is generated by the output address counter 45 based on the synchronizing signal. The data (infrared intensity data) in the address specified by this address data is γ
-Input to PROM46. The γ-PROM 46 converts the detected infrared intensity value into a luminance value on the CRT screen. At this time, the relation between the temperature of the object and the magnitude of the radiated infrared energy, the voltage value of the CRT signal and the screen Relationship with the above brightness,
Compensation (γ correction) such as the relationship between the amount of light incident on the human eye and the intensity of light perceived by humans (γ correction) to create linearity (linearity) between the temperature of the object to be measured and human perception give.

The output of the γ-PROM 46 thus γ-corrected is converted into an analog quantity by a D / A converter 47 and output to a display device (CRT) 49 of the viewer 18 via a synthesizing circuit 48 or a terminal 50
Output to the outside. Since the output of the synthesizing circuit 48 is in a composite (composite) video signal format, it can be used by various external devices, for example, can be observed by an external monitor television by a large number of people, and connected to a terminal 79. You can also record on a VTR. Note that the combining circuit 4
In step 8, various character information (described later) generated by the character generation circuit 51 is also input and incorporated into a video signal so as to be displayed on a screen.

<Switches> An infrared image is displayed on a CRT or the like as described above.
All operations of the present apparatus 10 including such processing are controlled by the CPU 52. Before describing this control, the functions of the various switches (see FIGS. 4 and 3) of the apparatus 10 will be briefly described below.

Mode key 53: Switches the screen display between an initial screen (described later) and an infrared image adjustment screen.

-Function selection (SELECT) key 54: Selects which set value is to be changed.

・ Up / Down key 55: Changes the selected setting value.

・ VTR key 56: When using a VTR, starts and stops the VTR.

・ O / W key 57: Switches the following three modes cyclically.

(A) Auto offset adjustment (b) Manual offset adjustment (c) Manual offset-window adjustment-+/- key 58: Seesaw type, + side or-side
Pressing the side raises or lowers the offset or changes the window. Release your finger to return to the neutral position.

・ F / M key 59: Switches the following three modes cyclically.

(A) Real-time temperature measurement (b) Infrared image screen freeze (c) Storing temperature value in memory and canceling freeze ・ W / B key 60: Select white or black high temperature area on screen I do.

・ Focus (F / N) key 61: Performs focusing.

In the device 10 of this embodiment, the key switches are connected as shown in FIG.
Detected by the CPU 52. In FIG. 7A, various key switches connected to the CPU 52 are collectively shown as 62.
Expressed as

<Overview of Various Functions of Apparatus> Next, various functions of the infrared imaging apparatus 10 in relation to the observation of the infrared image will be described.

Focusing When the focus key 61 on the right side of the grip 12 is pressed on the F (Far) or N (Near) side, the CPU 52 detects this and sends a forward or reverse rotation motor drive command signal to the focus lens drive circuit 63. Is output. As a result, the lens driving circuit 63 rotates the lens driving motor 64 forward or backward to move the infrared condenser lens 26.

-Offset adjustment The offset adjustment raises or lowers the level of the entire temperature range displayed on the screen. By pressing the O / W key 57, the CPU 52 alternately switches between the auto offset adjustment mode and the manual offset adjustment mode (including a mode in which the window can be further adjusted).

The offset adjustment of the present embodiment will be described with reference to FIG. 7 (b), which shows a circuit related to the offset adjustment, and FIG. 7 (c), which shows an example of a specific configuration of the offset injection circuit 33.

The polygon mirror 24 is provided with a chopper (not shown), and covers the detector 28 during a period in which the polygon mirror 24 is not scanning the object to be measured, and infrared rays from the object enter the detector 28. I try not to. Then, when the period starts, the timing generation circuit 41 outputs a pulse signal (referred to as a clamp pulse; s1 on the lower side in FIG. 14). Low-pass filter 32
The output signal s2 from is as shown in the upper part of FIG. 14,
Since the chopper covers the detector 28 during the clamp pulse, the signal s2 is a signal s3 corresponding to the energy radiated from the chopper itself (however, as shown in s4 in FIG. Is lower than the temperature of the chopper, the output may be lower than the signal s3.) Therefore, by clamping this signal s3 with an arbitrary offset voltage at the time of the clamp pulse, as shown in FIG. 15, the level of the entire output signal from the low-pass filter can be arbitrarily set within the offset voltage adjustable range r0. It can be changed to In FIG. 15, VA / Dmax
And VA / Dmin respectively indicate the maximum level and the minimum level at which the A / D converter 37 can perform analog-to-digital conversion, and finally the signal within this range is displayed on the screen in black and white. It is represented by shading. Therefore, when observing the part s5 where the infrared intensity is higher (the part with a higher temperature),
As shown on the left side of the figure, the offset level may be set low. If the offset voltage is set too high as shown on the right side of FIG. 15, the portion exceeding VA / Dmax will fly white (or black depending on the setting of the W / B key 60).

In the auto offset adjustment mode, the CPU 52
An automatic selection signal is sent to the manual switching circuit 66. Thus, the signal output from the comparison circuit 67 can pass through the automatic / manual switching circuit 66 and is input to the counter 68. The comparison circuit 67 outputs a down command signal when the average level of the signal output from the amplifier 36 is higher than the predetermined value Va, and outputs an amplifier command signal when the average level of the signal output from the amplifier 36 is lower than the predetermined value Va (that is, Vb <Va). I do. On the other hand, CPU5
The clock pulse from 2 is input to the counter 68, and the counter 68 increases or decreases the count value according to the up or down signal command from the comparison circuit 67 according to the number of clock pulses, and outputs the count value to the D / A converter 34. . This allows
The offset injection amount in the offset injection circuit 33 increases or decreases, and the output level of the amplifier 36 returns between Va and Vb. The offset is automatically adjusted by such feedback control. Note that the offset injection circuit 33 can be constituted by, for example, a circuit as shown in FIG. 7 (c) for each detection element of the infrared detector 28. The magnitudes of the reference voltages Va and Vb of the comparison circuit 67 are determined by circuit constants.

In the case of manual offset adjustment, CPU 52
A manual selection signal is sent to the manual switching circuit 66, and the signal from the comparison circuit 67 is invalidated. After doing so, the CPU 52 controls the clock pulse sent to the counter 68 by itself in accordance with the operation of the +/- key 58, and changes the offset by increasing or decreasing the output of the D / A converter 34.

It should be noted that the speed of the change of the offset can be made variable according to the gain of the amplifier 36, which will be described later in detail.

FIG. 7 (d) shows an embodiment of the comparison circuit 67, the automatic / manual switching circuit 66, and the counter 68.
The analog switch SW1 is controlled by the view signal output from the timing generation circuit 41 so as to be turned ON only while the polygon mirror 24 is scanning the effective view. The output signal of the amplifier 36 is input to the comparison circuit 67 while the analog switch SW1 is ON, and is averaged by the resistor R and the capacitor C. This average voltage is input to the non-inverting input terminal + of the comparator CP1 and the inverting input terminal-of the comparator CP2. On the other hand, the inverting input terminal of the comparator CP1
And the reference voltage Vb is input to the non-inverting input terminal + of the comparator CP2. With this configuration, when the average voltage is higher than Va, the comparator
When the signal of “1” is output from CP1 and the average voltage is smaller than Vb, the signal of “1” is output from comparator CP2. Then, these signals are input to the automatic / manual switching circuit 66.

The auto / manual switching circuit 66 has a CPU5
▲ ▼ / MANUAL signal output from 2 and UP / ▲
▼ Signal is input. In the auto offset adjustment mode, this ▲ ▼ / MANUAL signal is “0”
(Auto selection), the analog switch SW2 is turned on, and the analog switch SW3 is turned off. Therefore, the signal output from the comparator CP2 is input to the UP / ▲ ▼ terminal of the counter 68.

When the average voltage is higher than Va or lower than Vb, the output of the OR circuit OR1 becomes "1", and this signal is input to the enable (ENABLE) terminal of the counter 68. Then, the counter 68 counts clock pulses from the CPU 52. At this time, when the output of the comparator CP2 is “1”, that is, when the average voltage is smaller than Vb, the mode is the count-up mode, and by counting the clock pulses from the CPU 52, the output of the D / A converter 34 becomes growing. Then, the offset voltage increases,
The output of the amplifier 36 increases. The output of amplifier 36 is Va and Vb
, The input signal of the enable terminal of the counter 68 changes to “0”, the counting stops, and the change of the offset voltage stops. When the output of the comparator CP2 is "0", that is, the output of the comparator CP1 is "1", and the average voltage is larger than Va. At this time,
The counter 68 enters the countdown mode, and the clock pulse from the CPU 52 causes the output of the D / A converter 34 to decrease,
As described above, the operation stops when the average voltage becomes between Va and Vb. Thus, the offset amount is automatically adjusted, and the average voltage of the output of the amplifier 36 is maintained at a value between Va and Vb.

Next, in the manual offset adjustment mode,
Since the / MANUAL signal is "1" (manual selection signal), the output signal of the OR circuit OR1 becomes "1", and this signal is input to the enable terminal of the counter 68. That is, in the manual offset adjustment mode, the signal of “1” is always input to the enable terminal. At this time, the analog switch SW2 is turned off, and the analog switch SW3 is turned on. Therefore, the UP / ▲ ▼ terminal from the CPU 52 is connected to the UP / ▲ ▼ terminal of the counter 68.
A signal is input, and the counter 68 counts up or down based on this signal. Then, an offset amount is injected according to the count value. The UP / ▲ ▼ signal and the clock pulse are output in response to the operation of the +/− key 58, and are counted only while the +/− key 58 is operated. I have.

-Window adjustment Window adjustment changes the size of the temperature range displayed on the screen. This window adjustment includes:
There are a method of changing the gain of the circuit and a method of changing the transmittance of infrared rays by switching the range filter 70 in front of the detector 28. The change of the circuit gain is performed by the CPU 52 changing the gain of the amplifier 36. The switching of the range filter 70 is performed by the CPU 52 rotating the motor 72 using the filter driving circuit 71.

Temperature Calculation The signal from the detector 28 is input to the sample and hold circuit 75 at the stage when the signal is output from the preamplifier 31, and is sampled by a sampling signal from the CPU 52. The sampled and held signal is multiplexed by the multiplexer 76, digitized by the A / D converter 77, and input to the CPU 52. At this time, a signal related to the sensitivity (which varies depending on the temperature of the detector 28) from the detector 28 and a signal from a temperature-sensitive element 78 provided inside the device 10 are also input to the multiplexer 76. , Multiplexer 76 multiplexes these three signals and outputs them to CPU 52. The latter two signals are for correcting the former signal. The CPU 52 calculates the temperature of the device under test based on these three data. The above temperature calculation is
Executed when the F / M key 59 is pressed.

In addition to the functions described above, a character signal is also transmitted to the character generation circuit 51 to display the above-described character information such as the above-described calculated value of the measured object and the current time on the CRT screen.
The current time is obtained by accessing the clock IC80.

In addition to the programs that execute the functions described above,
All the operation programs of the CPU 52 are stored in the ROM 81.
The CPU 52 is further connected to a RAM 82 for temporarily storing data and an E ² PROM 83 for storing data even when the power is turned off. The E ² PROM 83 stores calibration information used when the CPU 52 calculates the temperature.

<Operation of CPU> Next, the operation of the CPU 52 will be described with reference to the flowcharts of FIGS. 9 (a) to 9 (i).

First, when the power of the apparatus 10 is turned on, step # 1 is executed.
Then, initialization (initialization) processing such as initialization of the internal registers of the CPU 52 and the RAM 82, and loading of the calibration information stored in the E ² PROM 83 into the RAM 82 is performed. Next, step # 2
Then, an initial screen as shown in FIG. 11 is displayed.

Here, the contents of the initial screen will be described with reference to FIG. In the upper area, information on the additional lens attached to the device 10 is displayed. In the area of the next stage, the unit of the temperature displayed thereafter is displayed. The current date and time are displayed in the lowermost area.

On this initial screen, the user can set the date and time and select the temperature unit. In step # 3, by flashing a specific character on the initial screen,
This indicates which item (set value) can be changed by the up / down key 55. For example, in FIG. 11A, the item value (“INTERNAL ONLY”, that is, only the internal lens) of the item (“LENS IN USE”) indicating the currently used lens is blinking, but the up / down key 55 is pressed. By pressing, the item value changes to “WIDE” (wide-angle lens etc.).

In step # 4, it is checked whether the mode key 53 has been pressed. If not, it is checked in step # 9 whether the function selection key 54 or the up / down key 55 has been pressed. If these keys have not been pressed, the process returns to step # 2. If it is determined in step # 9 that either the function selection key 54 or the up / down key 55 has been pressed, then in step # 10,
The setting of the initial display screen is changed in accordance with the pressed key, the display characters are changed in step # 11, and the process returns to step # 2. For example, the item of lens used (“LENS IN US
When the function selection key 54 is pressed while the item value of “E”) is flashing, as shown in FIG. 11 (b), the next item item value “C” of the temperature unit (“UNIT”) is displayed. Will begin to flash. When the function selection key 54 is pressed several times, the “second” of the current time display blinks. By pressing the up / down key 55 in that state, the display of the number of seconds is changed from “30” to “ 31 ”(FIG. 11 (c)).

If the mode key 53 is pressed in step # 4, the screen is switched to a screen for adjusting the infrared image in step # 5. That is, the screen of FIG. 11 is switched to the screen of FIG.

Here, the infrared image adjustment screen will be described. In the center of the screen, a large area for displaying the infrared image is provided, and additional information such as setting conditions relating to the infrared image is displayed on the left, right, and lower sides. The display area of each additional information will be described below.

Information on the focus is displayed in the uppermost area of the right column. Specifically, the focus key
When the F or N side of 61 is pressed, “F ↑” or “F ↓” is displayed.

Information about the window is displayed in the area in the next row. Specifically, any one of "H" / "M" / "L" is displayed with the switching of the range filter 70, and the displayed numerical value is between "1" to "7" with the change of the circuit gain. To change.

Offset information is displayed in the area. “OFA” is displayed in the auto offset adjustment mode, and “OFM” is displayed in the manual offset adjustment mode. Further, when the offset is changed by the +/- key 58 in the manual offset adjustment mode, "OFM ↑"
Or "OFM ↓" is displayed.

In the area, the current setting value of the emissivity (emissivity) is displayed.

When "LIST" is displayed in the area, the "LIST" is selected by pressing the function selection key 54, and when the up / down key 55 is pressed, as shown in FIG. 12 (b),
Data such as a temperature value stored in the memory is displayed on the screen. Briefly explaining the list in FIG. 12 (b), the numbers (1 to 10) in the leftmost column indicate recording numbers in the memory, and
Is newer and 10 is older. In the next column, the English character temperature measurement mode is indicated, where "S" indicates an instantaneous value, "AV1" and "AV2" indicate an average value, and "PK" indicates a peak value. The next “E” column is the emissivity, and the “T” column is the measured temperature value.

Returning to FIG. 12 (a), the above temperature measurement mode and the calculated temperature value are displayed in the area.

The display “V1” indicating that recording is in progress is displayed on the left side of the area below the infrared image display area, and the date and time are displayed on the right side, similarly to the initial screen.

 Gray scale is displayed in the leftmost column.

The thin column on the right side is an offset indicator for displaying the offset level.

The display of the offset indicator will be described in detail here. In the image memory 38, apart from the data area for displaying the infrared image, a screen data area for displaying the offset indicator is provided by the number of the scanning lines of the TV screen. The output address counter 45 sends the address of the screen data area corresponding to this display area to the image memory 38 during the period corresponding to the display of this area (t1 in FIG. 13 (a)). During this period (t2 in FIG. 13 (a)), the address of the area where the infrared intensity is written is sent to the image memory 38 as described above.

As described above, when the offset injection amount changes due to the automatic or manual offset adjustment, the CPU 52 can know the offset injection amount from the output count value of the counter 68. The count value of the counter 68 is D / A
If the converter 34 is for 10 bits, it is 0 to 1023. On the other hand, the number of effective scanning lines of the TV screen is generally 484 in the case of the NTSC system, but it is assumed that the offset indicator is represented by 400 in consideration of TV overscan.
As shown in FIG. 13 (a), if the offset indicator is represented by 40 to 439 lines, the relationship between the output count value DOF of the counter 68 and the corresponding TV line number LN is LN = −399 × (DOF −1023) / 1023 + 40 (1) The current offset value is displayed in an easy-to-understand manner on the offset indicator by calculating the address of the above memory area of the image memory according to this TV line number LN and writing data that serves as a mark in the area corresponding to the offset level Is done. For example, as shown in FIG. 13 (b), in the memory area corresponding to DOF = 0 to AD1 of the image memory 38, "110000B" (B represents a binary number), AD1 + 1 to
If data of "010000B" is written in AD2 and "110000B" is written in AD2 + 1 to 1023, the offset indicator on the screen displays gray-white-grey in order from the bottom.

Returning to the flowchart of FIG. 9A, step # 5
After switching to the infrared image adjustment screen in step # 6, the display of the item value of one item on the screen blinks in step # 6, indicating that the setting of the item can be changed. For example, in FIG. 12 (c), the display of “OFM” is blinking, indicating that the offset level can be manually changed at present. In FIG. 12 (d), “H6” is blinking, indicating that the window (range filter or gain) can be adjusted at present. Next, in step # 7, all key switches are scanned to check whether any key is pressed. If none of the keys has been pressed, the process returns to step # 5. If any key is pressed, the type of the key switch is determined in step # 8, and if the key is the mode key 53, the process returns to step # 2 to change to the display of the initial screen. If step # 12
Performs a process corresponding to each key switch. Hereinafter, processing when each key switch is pressed will be described with reference to FIGS. 9 (b) to 9 (i).

F / M key When the pressed key F / M key 59 is pressed, the routine of FIG. 9B is executed. In this routine, in steps # 20 and # 22, whether the value of the flag FRZ in the RAM 82 is 0 or 2 (if none, FRZ
= 1) is checked. This flag FRZ stores the current state of the temperature measurement mode, and its value corresponds to each of the following modes.

FRZ = 0: Screen freeze release mode. The storage of the temperature value in the memory is also performed.

FRZ = 1: Screen freeze mode. Fix the infrared image at a certain moment.

FRZ = 2: Real-time temperature measurement mode. An instantaneous infrared image is displayed on the screen.

If FRZ = 0 is determined in step # 20, the value of the flag FRZ is simply changed to 2 in step # 21, and the process returns to step # 5 in FIG. 9A.

When FRZ = 2, the value is changed to 1 in step # 23, and the screen display at that moment is fixed in step # 24. This is performed by prohibiting writing of output data of the infrared detector 28 into the image memory 38 and permitting only reading from the image memory 38.

FRZ is not 2 in step # 22 (that is, FRZ = 1)
In some cases, FRZ = 0 is set in step # 25, and step # 26
Then, the writing to the image memory 38 is permitted to release the frozen state of the screen. Then, in step # 27, the F / M key 59
Is pressed for a predetermined time (for example, 2 seconds) or more, and if it is pressed for a predetermined time or more, in step # 28, the temperature value and the like calculated in an interrupt routine described later are stored in the RAM 82.
To store. The data stored here is displayed as shown in FIGS. 12 (a) and (b) as described above. Next, in step # 29, the temperature display value calculated in the interrupt processing routine and displayed on the screen is cleared (erased). If it is determined in step # 27 that the F / M key 59 has not been pressed for a predetermined time or more, the temperature display value is cleared in step # 29, and the process returns to step # 5.

-W / B key When the pressed key is the W / B key 60, the most significant bit of the address data input to the γ-PROM 46 is inverted in step # 30 of FIG. 9 (c). In γ-PROM46,
Conversion table with high temperature as white and low temperature as black.
Two types of conversion tables are stored with white as the low temperature, and the usage table is switched by changing the value (0 or 1) of the most significant bit. Thereafter, the flow returns to step # 5.

・ Focus key If the pressed key is the focus (F / N) key 61,
The routine of FIG. 9D is executed. Here, in step # 31, a focus signal corresponding to the F side or the N side is sent from the CPU 52 to the focus lens drive circuit 63, and the condenser lens 26 is moved by the motor 64. In step # 32,
A signal is sent to the character generation circuit 51 to indicate that the key switch is pressed, and the character "F ↑" or "F ↓" is displayed in the area on the screen. And step #
Check if this key is kept pressed at 33,
If it has been pressed, the process returns to step # 31 to continuously send a focus signal. If the focus key 61 is no longer depressed, the process proceeds to step # 34 to stop the output of the focus signal, clear the character display in the area, and execute step # 5.
Return to

-VTR key If the pressed key is the VTR key 56, the routine proceeds to the routine of FIG. 9 (e), and in step # 35, the VTR start or stop signal is transmitted to the connector terminal 7 connected to the VTR machine.
Output to 9. If it is determined in step # 36 that the video is being recorded, a display "V1" indicating that is displayed in the lower area of the screen, and the process returns to step # 5.

-O / W key If the pressed key is the O / W key 57, the process proceeds to step # 37 of the routine in FIG. 9 (f), and the key is first pressed for a predetermined time (for example, 2 seconds). Check if it continues to be done. If the button is pressed for a predetermined time or more, a switching signal is sent to the auto / manual switching circuit 66 in step # 38, and the mode is switched between the auto offset adjustment mode and the manual offset adjustment mode. Then, in step # 39, the flag OW-FLAG in the RAM 82 is rewritten. This flag OW-FLAG is currently set to auto offset adjustment mode, manual offset adjustment mode,
This flag indicates which of the three states of manual offset-window adjustment mode. Thereafter, in step # 40, character information indicating the current state is displayed on the screen based on the value of the flag OW-FLAG, and the process returns to step # 5. In step # 6,
Based on the value of this flag OW-FLAG, the area on the screen (first
2) Refer to Fig. (A)) and blink the item value.
At 8, the operator is notified that offset adjustment or window adjustment is possible.

If the O / W key 57 has been pressed but has not been pressed for a predetermined time or more, the flag OW-FLA is set at step # 41.
It is checked whether or not the current state is the auto offset adjustment mode based on the value of G. If the mode is the auto offset adjustment mode, step # is performed without performing any processing.
Returning to step 5, if not, the process proceeds to step # 39, where the flag OW-FLAG is rewritten so that the mode is switched between the manual offset adjustment mode and the manual offset-window adjustment mode.

• +/- key If the pressed key is the +/- key 58, the process proceeds to step # 42 of the routine in FIG. 9 (g), where the flag OW-FLA is set.
By checking the value of G, it is determined whether the current mode is the mode for adjusting the offset or the mode for adjusting the window. In the (manual) offset adjustment mode, the clock pulse is output to the counter 68 in step # 43 to change the offset upward or downward. In step # 44, it is determined that the offset is currently changed. In order to indicate, using the character generation circuit 51, a character display “OFM ↑” is displayed in an area on the screen.
Or perform “OFM ↓”. Then, in step # 45, it is checked whether or not the +/- key 58 is still pressed, and if so, the flow returns to step # 43 to continue the offset adjustment. When the key 58 is no longer operated, the process proceeds to step # 46, in which the output of the clock pulse is stopped to change the offset, the character display on the screen is cleared, and the process returns to step # 5.

If it is determined in step # 42 that the current mode is the window adjustment mode, the gain of the amplifier 36 is changed or the range filter 70 is switched in step # 47. Display. At step # 49, as before, it is checked whether or not the +/- key 58 is kept depressed. If so, steps # 47 to # 49 are repeated, and if not, step # 50 is performed. Stop changing windows with step #
Return to 5.

-Function selection key If the pressed key is the function selection key 54, the flow advances to step # 51 in FIG. 9 (h) to change the value of the flag DSP-L in the RAM 82. The flag DSP-L indicates the item of the selected function. With this value, the emissivity can be changed at present (DSP-L = 0), and the temperature value stored in the RAM 82 can be displayed. (DSP-L = 1),
Which of the following three functions can be performed, and the temperature measurement mode can be changed (DSP-L = 2). The value of this flag DSP-L is used when step # 6 blinks on the screen, and determines which item is changed when the up / down key 55 is operated.

-Up / down key If the pressed key is the up / down key 55, the process proceeds to step # 52 in FIG.
It is checked whether the value of PL is 0.

If DSP-L = 0, the emissivity is increased or decreased in step # 53, and the changed emissivity value is displayed in the area on the screen in step # 54, and the process returns to step # 5.

If DSP-L = 0, DSP-L = 1 in step # 55.
Whether DSP-L = 1 or not, step # 5
At step 6, the temperature values and the like stored in the RAM 82 are displayed on the screen (see FIG. 12 (b)). And in step # 59,
It is checked whether or not the amplifier down key 55 has been pressed again, and the process waits in step # 55 until it is pressed. When the button is pressed again, the process returns to step # 5 for the first time.

When DSP-L = 1 is not satisfied, since DSP-L = 2,
In step # 58, the temperature measurement mode is changed. The temperature measurement mode includes an instantaneous value measurement mode for calculating an instantaneous value, an average value measurement mode for calculating an average temperature within a predetermined time (for example, 0.5 seconds or 2 seconds, etc.), and a peak value within a predetermined time. And a peak value measurement mode.
In step # 58, the three modes are sequentially switched. Then, in step # 59, the character display of the switched mode is performed on the area on the screen, and the process returns to step # 5.

The above is the description of the processing executed by the CPU 52 after the power supply of the present apparatus 10 is turned on.
The routine shown in FIG. 10 is processed by interruption every one rotation of (this can be detected by the output of the photo sensor 40). Upon entering this routine, first, in step # 70, it is checked whether or not an offset change is currently being performed based on the value of the flag OW-FLAG. In the auto offset adjustment mode, the count value is set during the execution of the routine in FIG.
Whether or not the offset has been changed can be determined based on whether or not the DOF value has changed from the previous value. In the manual offset adjustment mode, whether or not the +/- key 58 has been pressed is checked. Can be determined. If the offset has not been changed, it is checked in step # 71 whether or not the value of the flag FRZ is 2 (real-time temperature measurement mode). If not, the routine ends. The process proceeds to step # 72 only when FRZ = 2, and outputs a sampling pulse to the sample hold circuit 75 in order to sample the signal output from the preamplifier 36. Then, in step # 73, the sampled signal is converted into a digital signal by the A / D converter 77, and the sensitivity signal of the detector 28 and the signal from the temperature-sensitive element 78 are also A / D-converted, as described above. Multiplex and import to CPU52. In step # 74, based on these three values, the temperature of the device under test is calculated by adding a correction based on the temperature signal from the temperature-sensitive element 78. In step # 76, the temperature is displayed on the screen using the character generation circuit 51. Displays the value as text.

If it is determined in step # 70 that the offset is being changed, the flow advances to step # 77 to fetch the offset value DOF, and calculate the TV line number LN corresponding to the offset value DOF according to the equation (1). Then, in step # 78, the line number
The address of the image memory 38 corresponding to LN is calculated, and in step # 79, data serving as a mark ("010000B" in the above example) is written to the address, and this routine ends.
In this way, the current offset level is displayed on the screen in an easy-to-understand manner simultaneously with the infrared image.

Next, as another embodiment, an example in which the speed of the offset change is changed by the gain will be described. The reason for this is as follows. When the gain of the amplifier 36 is small, the amplitude of the signal input to the A / D converter 37 is generally small, as shown in FIG. Cannot be read in detail. Therefore, when it is desired to output a finer temperature difference on the screen (to increase the resolution), the gain of the amplifier 36 is increased as shown in FIG. 16 (b). As described above, the offset adjustment is performed by sending a clock pulse to the counter 68 and changing the count value DOF. Since the change in the count value DOF (that is, the change in the offset level) is also amplified by the amplifier 36, assuming that the frequency of the clock pulse is constant regardless of the gain, when the gain is small (FIG. 16 (a)). If the gain is large (FIG. 16 (b)) within the same time as the change from A to B in (a), the change greatly from A 'to B'. Therefore, when the gain is large, the level of the infrared image rapidly changes from black to white (or from white to black) within a short time, and the screen may fly to white (or black).

Further, in the auto offset adjustment mode, it takes time until the output of the amplifier 36 is read as the average voltage, so even if it is determined that the average voltage has reached the predetermined value and the change in the offset amount is stopped, Actually, it does not stop at the predetermined value, but exceeds the predetermined value. For example, to describe the case where the average voltage is adjusted to be between the reference voltages Va and Vb, when the average voltage is smaller than Vb and the offset amount is increased, the actual voltage when the average voltage reaches Vb is increased. The average voltage of the output of the amplifier 36 is Vb + α. This α
Is determined by the change speed of the output of the amplifier 36 and the delay time. Therefore, the faster the change rate of the output of the amplifier 36,
That is, the larger the gain of the amplifier 36, the larger this α, and depending on the gain of the amplifier, Vb + α may exceed Va. Then, the offset level oscillates, and the output of the amplifier 36 does not fall between Va and Vb.

Therefore, in this embodiment, when the gain is large, the CPU 5
2 reduces the frequency of the clock pulse supplied to the counter 68. By doing so, as the gain is larger, the offset level automatically and slowly changes, and the change in the output of the amplifier 36 becomes slower. Therefore, the oscillation described above does not occur in the auto offset adjustment mode. In addition, the offset adjustment can be easily performed even in the manual offset adjustment mode.

Further, such adjustment of the offset change speed is performed by + /
By adopting a structure as shown in FIG. 17 for the key 58, the operation can be performed manually (arbitrarily by the operator). Here, only the mechanism for tilting to the + direction is shown, but a comb-shaped moving piece 91 whose height is changed in three stages below the key switch 90 is provided. Are successively brought into contact with the fixed contact 92. The pulse generation circuit 93 outputs a pulse having a frequency that varies according to the resistance value that varies according to the number of contact points.
Send to U52. In the CPU 52, according to the frequency of this pulse,
The frequency of the pulse signal sent to the counter 68 is changed.

The flowchart of FIG. 18 shows a routine executed by the CPU 52 when the +/- key 58 is used.
Steps # 42-1 to # 42-3 are added between steps # 42 and # 43 in the flowchart of FIG. If it is determined in step # 42 that the mode is the offset adjustment mode,
In step # 42-1, a pulse generated by depressing the key switch 90 is input from the generation circuit 93, and step # 42 is entered.
The frequency f1 is calculated by -2. And step # 42-3
Then, the output f2 of the output pulse signal to the counter 68 is calculated from the input frequency f1 using a predetermined conversion formula (or conversion table), and the pulse signal is transmitted to the counter 68 at the frequency f2 in step # 43. As a result, the offset level is changed at a speed corresponding to the amount of depression of the key switch 90. That is, if the operator wants to change the offset slowly, he / she should press the +/- key switch 90 shallowly, and if he wants to change it fast, he / she needs to press deeply.

Effect of the Invention As described above, according to the present invention, since the offset level appears on the screen at the same time as the infrared image, it is very easy to adjust the offset level, and even if the infrared image changes, the offset level is kept constant. It can be adjusted to a value. Also, since the speed of changing the offset level is variable depending on the gain and the amount of switch depression,
This makes it easy to operate the offset level in a wide range or finely change the offset level.

[Brief description of the drawings]

1 (a) to 1 (c) are claims correspondence diagrams of the present application, FIG.
3A and 3B are a plan view and a front view of a grip portion of the portable infrared imaging apparatus according to an embodiment of the present invention, and FIG. FIG. 5 is a view showing the appearance of the switch, and FIG.
FIG. 6 is a diagram showing the principle of infrared imaging of this apparatus, and FIGS.
(D) is an electric circuit diagram of the apparatus, FIG. 8 is a connection diagram of various switches, FIGS. 9 (a) to (i) are flowcharts of routines routinely executed by the CPU of the apparatus, and FIG. 11A to 11C are flowcharts of a routine executed by interruption every rotation of the polygon mirror. FIGS. 11A to 11C show examples of initial screens appearing on a viewer CRT. FIGS. 12A to 12D. Fig. 13 shows an example of an infrared image adjustment screen, Figs. 13 (a) and 13 (b).
Is a diagram for explaining a correspondence relationship between an offset indicator on a screen and data in an image memory, FIG. 14 is a timing chart showing a relationship between a signal from an infrared detector and a clamp pulse for offset clamp, and FIG. Explanatory drawing showing the relationship between the A / D convertible range and the offset level, FIG.
16 (a) and 16 (b) are explanatory diagrams showing the relationship between the magnitude of the gain and the speed of changing the offset level. FIG. 17 is a structural diagram of a switch for generating a pulse signal according to the amount of depression, and FIG.
The figure is a flowchart of the operation of the CPU when the switch is operated. 10 Infrared imaging device 12 Grip 14 Body 16 Battery pack 18 CRT viewer 24 Polyhedral mirror 26 Infrared condenser lens 28 Multi-element infrared detector 53 Mode key 54 …… Function selection key 55 …… Up / down key 56 …… VTR key 57 …… O / W key 58 …… +/− key 59 …… F / M key 60 …… W / B key 61 …… Focus key

──────────────────────────────────────────────────続 き Continuation of the front page (72) Yuji Takumiya 2-3-3 Azuchicho, Chuo-ku, Osaka-shi, Osaka, Osaka International Building Minolta Camera Co., Ltd. (56) References JP-A-51-58386 (JP, A) JP-A-1-105124 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01J 5/48

Claims (2)

(57) [Claims] 1. An infrared imaging apparatus for two-dimensionally scanning an object to be measured, receiving infrared rays, and converting the intensity of the infrared rays into image data to be shaded on a screen. A means for changing an offset level defined as an infrared intensity to be converted to a predetermined reference density, and adding offset display data to the image data so that the offset level is displayed simultaneously with the infrared image on a screen. An infrared imaging apparatus, comprising: means for changing a gain when converting infrared light into image data; and means for changing a speed of changing an offset level according to the gain. 2. An infrared imaging apparatus for two-dimensionally scanning an object to be measured, receiving infrared rays, and converting the intensity of the infrared rays into image data to be shaded on a screen. A means for changing an offset level defined as an infrared intensity to be converted to a predetermined reference density, and adding offset display data to the image data so that the offset level is displayed simultaneously with the infrared image on a screen. An infrared imaging device, comprising: a key switch for outputting a signal corresponding to a depression amount; and a unit for changing a speed of changing the offset level according to an output signal from the key switch.