JPH02140075A - infrared imaging device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [) Already Required] An object of the present invention is to provide an infrared imaging device that is capable of visually confirming a subject without using a visible camera, particularly regarding a method for visually detecting the imaging range of a subject. The infrared rays emitted from the object are received by an infrared detector through a scanning optical system and an imaging lens, and the photoelectrically converted output signal of the infrared detector is displayed on a TV monitor as a temperature distribution pattern of the object. In the infrared imaging device shown in FIG. is incident on the subject, and the reflected light passes through the scanning optical system and irradiates the subject in a direction opposite to the infrared light received from the subject, and the subject is illuminated by the laser light emitted from the scanning optical system. Make the range recognizable and compose it.

[Industrial application field]

The present invention relates to an infrared imaging device, and particularly to a method for visually detecting an imaging range of a subject.

Infrared imaging devices display the temperature distribution of the subject on the monitor screen, but subjects with little temperature change or flat subjects facing the camera (for example, walls) may not be visible from the monitor screen as being the actual subject. It was difficult to know the imaging range. That is, it is difficult to know where the temperature distribution on the monitor screen is in the actual subject.

Therefore, it is desired to develop a detection means that can clarify the imaging range of a subject in an infrared imaging device.

[Conventional technology]

FIG. 3 shows a block diagram of a conventional single-lens image superimposing device. In the figure, 1 is a subject, and 2 is a wavelength selective filter that optically separates visible light and infrared light on the same optical axis.The visible light contained in the incident light is reflected and the visible light contained in the incident light is reflected. Infrared light is transmitted and separated. 3 is a reflecting mirror, 4 is an infrared camera, 5 is a visible camera, 6 is an addition circuit that adds the video signals output from each camera while synchronizing them, and 7 is a T that displays the added composite video signal as a superimposed image.
V monitor is shown.

FIG. 4 shows a professional diagram of a conventional twin-lens image superimposing device. In the figure, blocks with the same symbols as in FIG. 3 indicate the same parts. In the figure, 8 and 8 are infrared camera 4, respectively.
and shows an optical axis setting table for adjusting the optical axis viewing angle of the visible camera 5. The infrared camera 4 and the visible camera 5 are arranged close to each other, and each observes the same subject 1 from different optical axes.

FIG. 5 is a diagram showing parallax in the two-lens system.

Visible image v at distance L2 from both cameras to the subject
2 and the infrared image R2, the angle θ (parallax) formed by the optical axis between both cameras and the viewing angle θV of the visible camera.
, it is assumed that the viewing angles θr of the infrared cameras are set to be equal. In this state, if you observe an object at a closer distance or a farther distance L3, the visible/infrared image will have V+/R+, V*/lh due to the parallax θ, as shown in the figure.
This will cause a shift like this.

In the conventional method, as a means for correcting this shift, an optical axis setting table 8.8'' shown in FIG. 4 was used to adjust the parallax θ each time so that the viewing angles of both cameras were equal.

[Problem to be solved by the invention]

The single-lens image superimposition device shown in FIG. 3 has the advantage of reducing parallax, but has the disadvantage of being expensive and large because it requires a visible/infrared separation optical system. In addition, the twin-lens image superimposition device shown in Fig. 4 has a simple configuration, is suitable for miniaturization, and is inexpensive, but because it performs observation on the optical axis, which is a field of view, it suffers from parallax as explained in Fig. 5. It is large and requires constant adjustment of the orientation of both cameras using optical axis setting tables 8, 8' depending on the distance to the subject, which has the disadvantage of being complicated.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide an infrared imaging device that allows visual confirmation of a subject without using a visible camera.

Means for Solving C5a] FIG. 1 is a diagram showing the principle of the present invention. The infrared rays emitted from the subject 1 are received by the infrared detector 14 via the scanning optical system 9 and the imaging lens 13, and the output signal of the infrared detector 14, which has been photoelectrically converted, is used as the temperature distribution pattern of the subject 1. In an infrared imaging device displayed on a TV monitor 7, a reflecting mirror 16 that is sufficiently small compared to the diameter of the imaging lens 13 is provided on the central optical axis between the scanning optical system 9 and the imaging lens 13. At the same time, a laser beam tp, 17 is provided which makes a laser beam incident on the reflecting mirror I6, and the reflected light passes through the scanning optical system 9 and irradiates the subject in a direction opposite to the infrared light received from the subject 1. The configuration is such that the range illuminated by the laser light emitted from the scanning optical system 9 can be recognized.

[Function] The laser light emitted from the laser light source 17 is reflected by the reflecting mirror 16, and the reflected light passes through the optical axis of the imaging lens 13.
The infrared rays incident from the subject 1 travel backward along the central optical path and are irradiated onto the subject 1 from the scanning optical system 9 through the window 8. Since the laser beam is on the optical axis for infrared scanning, the infrared scanning and the laser scanning coincide, so the irradiated position of the subject l and the position of the infrared image coincide. The irradiated area changes according to the scanning direction of the scanning optical system 9, but the infrared imaging device can visually confirm the shape of the object 1 illuminated by the laser beam due to the afterglow characteristics of the human eye. The captured imaging range can be detected, and a specific portion can be easily understood by comparing it with the temperature pattern screen displayed on the TV monitor 7 via the image processing device 15.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

In order to make the explanation of the configuration and operation easier to understand, the same parts will be denoted by the same reference numerals throughout the design and their repeated explanation will be omitted.

FIG. 2 shows a block diagram of an embodiment of the invention.

In the figure, infrared rays emitted from a subject 1 pass through a window 8 and enter a scanning optical system 9.

10a is a galvano drive circuit for scanning and driving the vertical galvano mirror 10 in the vertical direction; 1A is a galvano drive circuit for scanning and driving the horizontal galvano mirror 10 in the horizontal direction; .

1) Both galvano mirrors 1 scanned by a(7) drive
Together with a galvano position detection circuit 18 for detecting a galvano position of 0° 1) and a fixed mirror 12, the scanning optical system 9 shown in FIG. 1 is constituted.

Infrared information emitted from the subject 1 is focused on the light receiving surface of the infrared detector 14 (for example, a -dimensional multi-element detector) via the scanning optical system 9 and the imaging lens 13, and is focused on the light receiving surface of the infrared detector 14 (for example, a -dimensional multi-element detector). Spatial brightness change information in a direction perpendicular to the rows of the multi-element detectors 14 is output as a temporal change in voltage. The -dimensional multi-element detector 14 outputs pixel data for one screen in one scan of the scanning optical system 9.

Reference numeral 19 denotes an amplifier that improves the S/N of infrared information contained in the multi-element parallel signal outputted by the infrared detector 14, and outputs it as a time-series signal via a multiplexer or the like (not shown).

A CPU 20 controls image processing in response to the output of the video synchronization signal generation circuit 21 and the output of the galvano position detection circuit 18. 22 is an A/D converter that converts the time-series signal output of the amplifier 19 into a digital signal using the timing signal output from the video synchronization signal generation circuit 21; The storing frame memory 24 is a TV signal generator for reading out the infrared information stored in the frame memory 23 as a video signal for the TV monitor 7.

The configuration described above is the general content of conventionally used infrared imaging devices.

The reflecting mirror 16 is equipped with a reflecting surface that is sufficiently small compared to the diameter of the imaging lens 13, and is located between the fixed mirror 12 at the end of the scanning optical system 9 and the imaging lens 13, and between the imaging lens 13 and the imaging lens 13. The image lens 13 is fixedly held on the central optical axis by a thin metal wire or the like so as not to block incoming infrared rays as much as possible. The laser light source 17 emits the laser beam, and the laser beam is reflected by the reflecting mirror 16, and the direction of the reflection is on the central optical axis of the imaging lens 13, and it is different from the infrared rays incident along the central optical axis of the parentheses. Set it so that it goes in the exact opposite direction. For example, a semiconductor laser or the like can be used as the laser light source 17.

During the period when the infrared image (temperature distribution pattern) of the subject 1 is displayed on the TV monitor 7 as an image, the position signals of the galvano drive circuits 10a and 10b are transmitted to the galvano position detection circuit 18.
is detected, the CPU 20 determines the video period, the video synchronization signal generation circuit 21 controls the A/D converter 22, and at the same time controls the laser drive circuit 25, so that the laser light source emits laser light only during the video display period. do it like this.

As a result, the laser beam reflected by the reflecting mirror 16 travels backward along the incident optical path of the infrared rays, and passes through the scanning optical system 9 and the window 8.
The object 1 is irradiated through the. The irradiated area changes according to the scanning direction of the scanning optical system 9, but the shape of the subject 1 illuminated by the laser beam can be determined by the afterglow characteristics of the human eye using the same principle as when viewing a television image. As a result, the imaging range captured by the infrared imaging device can be detected, and the image processing device 1
By comparing the screen with the infrared image displayed on the TV monitor 7 via the screen 5, a specific portion on the screen can be easily understood.

Since the reflecting mirror 1G is held on the central optical axis of the imaging lens I3, there is a concern that infrared rays incident on this central optical axis may be blocked from reaching the infrared detector 14. It has been experimentally confirmed that since the dimensions of the lens 16 are sufficiently small compared to the diameter of the imaging lens 13, the effect thereof is of a level that does not pose a practical problem.

Furthermore, the visual effect can be improved by using a wavelength-tunable dye laser as the laser light source 17 and selecting the color of the laser light to be irradiated in accordance with the surface color of the subject 1.

C. Effects of the Invention] As is clear from the above description, according to the present invention, the range where the object is imaged is illuminated by laser light, and the range of the infrared image can be visually confirmed. , small size because it does not require devices such as adder circuits,
Can be configured to be lightweight. Furthermore, there is no need for adjustment even when the imaging distance changes, and it is easy to use and has a significant industrial effect in that it contributes to improved performance.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a block diagram of a conventional single-lens image superimposition device, and Fig. 4 is a conventional twin-lens image superimposition device. A block diagram of the superimposition device, FIG. 5 is a diagram showing parallax in the two-lens system. In Fig. 1, ■ is the subject, 7 is the TV monitor, 9 is the scanning optical system, 13 is the imaging lens, 14 is the infrared detector, 1
6 indicates a reflecting mirror, and 17 indicates a laser light source.Figure 2Figure 1

Claims (1)

[Claims] Optical system (9) that scans infrared rays emitted from the subject (1)
and an infrared detector (14) via an imaging lens (13).
In the infrared imaging device, the scanning optical system (9) displays an output signal of the infrared detector (14) that is received and photoelectrically converted on a TV monitor (7) as a temperature distribution pattern of the subject (1). A reflecting mirror (16) that is sufficiently small compared to the diameter of the imaging lens (13) is provided on the central optical axis between the imaging lens (13) and the imaging lens (13).
16) is provided with a laser light source (17) for irradiating the subject with a laser beam and the reflected light passes through the scanning optical system (9) and irradiates the subject in a direction opposite to the infrared light received from the subject (1); An infrared imaging device characterized in that the range illuminated by the laser light emitted from the scanning optical system (9) can be recognized.