JPH0210426Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for automatically performing focusing in a thermographic apparatus.

In a thermography apparatus, for example, as shown in FIG. 1, an optical system consisting of a scanning mirror 1, a condensing mirror 2, and a lens 3 is used to form an image spot of an infrared detector 4 on a subject. The image spot is scanned two-dimensionally, and the detector 4
The infrared video signal obtained from the camera is sent to a display device to display a temperature distribution image of the subject.
At this time, focusing is carried out by moving the condensing mirror 2 step by step in the direction of the arrow, and differentiating the video signal obtained by horizontally scanning the same position each time.The video signal containing the signal with the largest peak-to-peak value is then This is done by fixing the condensing mirror 2 at the position where it is obtained. However, when scanning the same position horizontally, a peak tends to form at the edge of the subject, so there is a strong possibility that this area will be focused, and the depth will be significantly different between the part you actually want to focus on and the edge. In this case, there was a risk that the part you wanted to observe would be blurred.

This idea was made in view of these points,
An object of the present invention is to provide a device that can automatically focus on a predetermined portion in a temperature distribution image and display the predetermined portion on a screen.

FIG. 2 shows the configuration of one embodiment of the present invention.
Components that are the same as in the figures are given the same numbers. In FIG. 2, the scanning mirror 1 is repeatedly horizontally scanned by a motor 5 and vertically scanned by a motor 6. In FIG. The motor 6 tilts the scanning mirror 1 by a small angle for each horizontal scan based on the horizontal synchronization signal PH sent from the motor 5, thereby performing one vertical scan for every 200 horizontal scans. The infrared image signal obtained from the detector 4 during such horizontal and vertical scanning is sent to the linearizer 7, where it is converted into a temperature signal having a linear relationship with temperature, and then sent to the cathode ray via the adder 8. It is supplied as a luminance signal to the grid of tube (CRT) 9. At this time, the deflectors 10H and 10V of the CRT 9 are supplied with the sawtooth waveform horizontal scanning signal SH and vertical scanning signal SV, respectively, which are created in the scanning circuit 11 based on the horizontal synchronizing signal PH and the vertical synchronizing signal PV generated from the motor 6. Therefore, a temperature distribution image Z having brightness and darkness corresponding to the surface temperature of the subject is displayed on the screen as shown in FIG.

12V, 12H ₁ , 12H ₂ are potentiometers for specifying any part within the field of view.
is the vertical position b, 12H ₁ is the horizontal starting point position a ₁ , and 12H ₂ is the horizontal ending point position.
a ₂ , each magnitude comparator 1
Send to 3V, 13H ₁ , 13H ₂ . The comparator 13V compares the vertical scanning signal PV and the b,
If they match, the matching pulse signal is sent to the comparator 1.
Send to 3H ₁ , 13H ₂ . The comparator 13H ₁ ,
13H ₂ is the horizontal scanning signal PH and the a ₁ and a ₂ respectively.
If they match, matching pulse signals are sequentially sent to the flip-flop circuit 14. The flip-flop circuit creates a pulse signal based on the sequentially inputted pulse signals, and supplies it to the CRT 9 as a luminance signal via the adder circuit 8. Therefore, on the screen, as shown in Figure 3, there is a weight on the image Z,
A white line marker B is displayed at vertical position b and between horizontal positions _a1 and _a2 . The display position of this marker B is the potentiometer 12V, 12
It can be set arbitrarily by adjusting H ₁ and 12H ₂ . Although the marker B is displayed as a white line, the luminance signal of this portion may not be sent to the CRT 9 and may be displayed as a black line. Also, without using a potentiometer, marker B can be set using an electronic computer.
Alternatively, the user may be asked to specify the position where the image should be displayed.

The present invention displays the portion B designated by the above-mentioned position setting means on the screen, simultaneously extracts a video signal corresponding to the portion B, and automatically performs focusing based on this video signal. It is characterized by That is, the condensing mirror 2 is provided so as to be movable in the direction of the arrow by the rotation of a threaded rod 17 that is screwed into a nut 16 attached to the rear surface. 18 is a pulse motor coupled to the threaded rod 17;
Since the motor 18 is supplied with a drive pulse generated in the drive circuit 19 based on the horizontal synchronization signal PH via the switch 20, the motor 1
8 rotates by a predetermined angle for each horizontal scan.
Therefore, the condensing mirror 2 is sequentially moved in steps for each horizontal scan. The temperature signal obtained with repeated horizontal scanning is sent to the differentiation circuit 21 and differentiated, and the obtained differential signal is sent to the diode 22.
Only the positive signal is sent to the A-D converter 24 via the switch 23 and converted into a digital signal, and then sent to the maximum value detection circuit 27 composed of a latch circuit 25 and a comparator 26 to detect the maximum value. Detected. 28 is a latch circuit for storing the position of the condenser mirror 2 when the maximum value is detected;
The output of an up-down counter 29 for counting horizontal synchronizing signals is supplied to the latch circuit as a position signal via a switch 30. When the driving circuit 19 completes the movement of a predetermined number of steps from the end (corresponding to the focal length ∞) to the end (corresponding to the shortest focal length) of the condensing mirror 2, the driving circuit 19 reverses the rotational direction of the pulse motor 18 and focuses the light. While moving the mirror 2 in the returning direction, the counter 29 is switched to the down count mode by issuing the inversion signal Q, and the switch 30 is also switched. During this return period, the coincidence detector 31 compares the output of the counter 29 and the output of the latch circuit 28,
When the two match, a match signal R is generated. The switch 20 is turned off by this coincidence signal R, and the pulse motor 18 is stopped. 32 is a switch that starts focusing, and the power switch 33 of the motor 6 is activated by the coincidence pulse signal sent from the comparator 13V via this switch.
turns off. When the power switch 33 is turned off, the switches 20 and 3 that are in an interlocking relationship with it are turned off.
4 is turned on, and a pulse signal from the flip-flop circuit 14 is sent to the switch 23 via the switch 34.

In the above configuration, the switch 33 is turned on.
When the switch is turned on to command focusing while the scanning mirror 1 is being scanned horizontally and vertically, the coincidence pulse signal generated when the vertical scanning reaches position b in FIG. 3 is transmitted through the switch 32. is sent to the switch 33, and the switch 33 is turned OFF.
Since this state is maintained, the vertical scanning stops at the position b, that is, the position of the marker line _L2 , and only the horizontal scanning is repeated at that position. At this time, the switch 20 is linked to the switch 33.
is turned on, and a drive pulse synchronized with horizontal scanning is sent from the drive circuit 19 to the pulse motor 18, so that the condenser mirror 2 moves from the position P ₁ of focal length ∞ to the position P ₂ of the shortest focal length every horizontal scan. Move step to step. By repeating horizontal scanning while changing the focal length in this way, the obtained temperature signal will start out of focus, and as it comes into focus, the waveform will gradually become sharper, as shown in Figure 4a. Become something. Therefore, the differential signal also gradually shows larger peaks, as shown in FIG. The differential signal is transmitted through the diode 22, and only the positive signal is shown in FIG.
As shown in FIG. 2, the signal is taken out and sent to the maximum value detection circuit 27. At this time, the switch 23 synchronizes with the pulse signal from the flip-flop circuit 14 and detects the pulse width of the pulse signal t(a ₂ -a ₁ ). Therefore, what is ultimately sent to the maximum value detection circuit 27 is the temperature signal of part B corresponding to the period t from point a ₁ to point a ₂ as shown in FIGS. 3 and 4 d.

The detection circuit 27 is composed of a latch circuit 25 that stores the maximum value of the previous data, and a comparator 26 that compares the maximum value with the current data. When this occurs, a store signal is generated and the current data is stored in the latch 25 as the maximum value.
Since the store signal is also sent to the latch circuit 28, the current count value of the up-down counter 29, which counts the horizontal scanning circuit (step movement circuit) from the start of focusing, is stored in the latch circuit 28. Ru. Therefore, P ₁ of condenser mirror 2
When the movement from P2 to _P2 is completed, the latch circuit 25 stores the maximum value of the differential peak during that time, and the latch circuit 28 stores the value when the maximum value of the differential peak is obtained (that is, the focus is in focus). A count value N indicating the position of the condenser mirror 2 at the time of
If the condensing mirror 2 is placed at the position of this count value N, it will be in focus. In this embodiment, the condenser mirror 2
Using the return of , the condenser mirror 2 is stopped at the position of the count value N as described below.

That is, the drive circuit 19 performs a predetermined number of steps (for example,
When it is detected that the condensing mirror 2 has reached the position P ₂ by the movement of 200), the pulse motor 18 is reversed,
The counter 29 is moved step by step from P ₂ to P ₁ in each horizontal scan, and an inverted signal Q is generated to set the counter 29 in a down count mode and switch 30 to the coincidence detector 31 side. Therefore, counter 29
The count value decreases sequentially from 200 when _P2 is reached, and when the count value returns to N, the coincidence detector 3
1, a coincidence signal R is generated. At this time, the condensing mirror 2 is at a position where the focus is correct, and if the switch 20 is turned off in response to the coincidence signal and the condensing mirror 2 is stopped at that position, the focusing has been performed correctly. Moreover, the temperature signals used for focusing are potentiometers 12V, 12H ₁ , 12H ₂
Since it is of the portion B specified by , the focus will be best placed near the portion B. Therefore potentiometer 12V, 12H ₁ , 12H ₂
By adjusting and setting portion B at an arbitrary position on the screen, it is possible to focus on an arbitrary position on the subject.

As described in detail above, according to the present invention, it is possible to select any part on the subject, display that part on the screen, and automatically focus on the part, making it extremely easy to find the part you want to observe. You can focus on.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the scanning optical system, Figure 2 is a diagram for explaining the scanning optical system.
3 is a diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a diagram showing a screen display format, and FIG. 4 is a waveform diagram for explaining the operation of the embodiment. 1: scanning mirror, 2: condensing mirror, 3: infrared detector,
5, 6: Motor, 8: Adder, 9: CRT, 1
1: Scanning circuit, 12V, 12H ₁ , 12H ₂ : Potentiometer, 13V, 13H ₁ , 13H ₂ : Magnitude comparator, 14: Flip-flop circuit, 16: Nut, 17: Threaded rod, 18: Pulse motor, 19 : Drive circuit, 20, 23, 3
0, 32, 33, 34: switch, 21: differential circuit, 22: diode, 25, 28: latch circuit, 26: comparator, 27: maximum value detection circuit, 28: up/down counter, 31: coincidence detector.

Claims (1)

[Scope of utility model registration request] The infrared detector includes a condensing means for focusing the image spot of the infrared detector on the subject, and a scanning means for scanning the image spot on the subject in horizontal and vertical directions. A thermography device configured to display a temperature distribution image of a subject by supplying an infrared image signal obtained from a means for setting a specified part; a means for displaying the specific part on the display means; a means for extracting a video signal corresponding to the specific part from an infrared video signal based on the output of the setting means; means for obtaining an information signal regarding the focal point; means for storing a signal corresponding to the focal length of the focusing means when the information signal indicates an optimum value; and means for setting the focal length of the means to a value when the information signal indicates an optimum value.