JPH04357770A - Infrared ray image pickup device - Google Patents

Abstract

PURPOSE:To obtain an infrared ray picture signal between at least wide and narrow field of view angles simultaneously and economically on the infrared ray image pickup device having different field of view angles. CONSTITUTION:The optical systems 1-1 to 1-n of different field of view angles theta1 to thetan are switched by an optical changeover part 2 in the prescribed order and inputted to an infrared ray image pickup device 3. A switch circuit 4, inputting the infrared ray picture signal from this infrared ray image pickup element 3 after switching it to picture processing parts 5-1 to 5-n corresponding to the optical systems 1-1 to 1-n, is operated in synchronism with the optical changeover part 2. Thus, the infrared ray picture signal with different field of view angles theta1 to thetan can be obtained time-divisionally.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared imaging device having different viewing angles. 2. Description of the Related Art Infrared imaging devices are capable of capturing images at night or when visibility is poor due to fog, smoke, etc., and are therefore used in a variety of applications. For example, in search activities at night, etc., a wide imaging field of view and a narrow imaging field of view for tracking a specific target are required. Therefore, it is desired to economically realize an infrared imaging device having such different viewing angles.

0002

[Prior Art] Infrared imaging devices are made of semiconductors such as silicon (Si), which have spectral sensitivity at longer wavelengths than visible light, or
One infrared sensing element made of a compound semiconductor such as aInAs
A configuration in which the above-mentioned infrared detection elements are arranged in a one-dimensional array and optically scans in a direction orthogonal thereto, or a configuration in which the above-mentioned infrared detection elements are arranged in a two-dimensional array and the electronic There are configurations such as those that scan automatically.

[0003] When using such an infrared imaging device for search activities or target tracking control in times of poor visibility, conventionally, for example, at least two devices, one with a wide viewing angle and one with a narrow viewing angle, are used. An infrared imaging device with a wide viewing angle was used to perform overall observation, and a narrow viewing angle infrared imaging device was used to control tracking of the target. If it is not possible to install two infrared imaging devices, the operator can switch the optical system as necessary.
Observations were made by switching between a wide viewing angle and a narrow viewing angle.

0004

[Problems to be Solved by the Invention] In an infrared imaging device that requires at least a wide viewing angle and a narrow viewing angle, it is difficult to provide two infrared imaging devices as in the conventional example described above. There are problems with space, weight, etc. constraints on vehicles, aircraft, etc. that carry the device. Furthermore, there is also the problem of increased costs due to the use of two units. In addition, if a wide viewing angle and a narrow viewing angle are to be realized by switching the optical system, one infrared imaging device is sufficient, but it is possible to simultaneously capture a wide viewing angle image and a narrow viewing angle image. Therefore, there is a problem in that tracking of a target object is also hindered. An object of the present invention is to simultaneously obtain at least wide viewing angle and narrow viewing angle images by time-divisionally obtaining infrared image signals for at least wide viewing angle and narrow viewing angle.

[0005]

[Means for Solving the Problems] The infrared imaging device of the present invention will be described with reference to FIG. -1 to 1-n in a predetermined order using a mirror or the like; an infrared imaging element 3 to which the optical image switched by the optical switching unit 2 is input and outputs an infrared image signal; The infrared image signal from the image sensor 3 is switched in synchronization with the optical switching unit 2, and the optical system 1-1 to
1-n, and a switch circuit 4 for inputting to image processing units 5-1 to 5-n corresponding to image processing units 1-n.

[0006] Also, it is provided with a first optical system having a wide viewing angle and a second optical system having a narrow viewing angle, and inputs an optical image by the first optical system to the infrared imaging element 3 during forward scanning by reciprocating scanning. ,
The optical switching unit 2 may be configured to switch so that the optical image by the second optical system is input to the infrared imaging device 3 during the backward scan of the reciprocating scan.

[0007]

[Operation] Optical system 1- with different viewing angles θ1 to θn
1 to 1-n, optical images with different imaging ranges can be obtained. The respective optical images are switched in a predetermined order by the optical switching unit 2 and input to the infrared imaging device 3. In that case, the infrared sensing elements are arranged two-dimensionally and the infrared imaging element 3
When configured, two-dimensional scanning is performed electronically and an infrared image signal is output. Further, when the infrared imaging device 3 is constructed by arranging infrared detection elements one-dimensionally, a mechanism for optically scanning the optical image switched by the optical switching section 2 is provided. Further, when the infrared imaging device 3 is configured with one infrared detection element, a mechanism for optically two-dimensionally scanning the optical image is provided. Further, the switch circuit 4 switches the infrared image signal of the infrared image sensor 3 in synchronization with the switching of the optical image by the optical switching section 2, and switches the infrared image signal of the infrared image sensor 3 to
For example, when an optical image of a wide viewing angle optical system is selected, an infrared image signal is input to the corresponding image processing units 5-1 to 5-n. For example, display processing of a wide range of images is performed.

Further, the optical scanning is a reciprocating scan, and an optical switching unit 2 switches the optical image formed by the optical system between a wide viewing angle and a narrow viewing angle during the forward scanning and the backward scanning. Therefore, an infrared image signal with a wide viewing angle and an infrared image signal with a narrow viewing angle can be obtained in a time-division manner.

[0009]

[Embodiment] FIG. 2 is a block diagram of an embodiment of the present invention.
This shows a configuration in which the optical system is switched between a wide viewing angle and a narrow viewing angle, and 11, 12, and 13 are lenses constituting the first and second optical systems, 14 is an optical switching section, 15 is an optical scanning section, 16
is an infrared imaging device with a one-dimensional array of infrared sensing elements, 1
7 is a switch circuit, 18 and 19 are first and second image processing units, 20 is a control circuit, and 21 is a mirror.

The viewing angle θ1 of the first optical system formed by lenses 11 and 13 is a wide angle, and the viewing angle θ2 of the second optical system formed by lenses 12 and 13 is a narrow angle. In this case, the lens 13 corresponds to an imaging lens. Further, the optical switching unit 14 is controlled by the control circuit 20 to switch the mirror 21 between the solid line position and the dotted line position. When the mirror 21 is switched to the dotted line position, the optical image by the first optical system is input to the infrared image sensor 16 via the optical scanning unit 15, and when the mirror 21 is switched to the solid line position, the optical image from the first optical system is input to the infrared image sensor 16. An optical image formed by the optical system is input to the infrared image sensor 16 via the optical scanning section 15. Further, the optical switching unit 14 may be configured by providing a shutter that opens and closes alternately between the first and second optical systems and the infrared imaging element 16 via the optical scanning unit 15.

The optical scanning unit 15 has a scanning mechanism that uses reciprocating scanning of a mirror, rotational scanning of a polygon mirror, etc., and scans an optical image under the control of a control circuit 20. The lens 13 is configured to input an optical image to the lens 13, and depending on the configuration of the lens system, the lens 13
It is also possible to place it after the . Also switch circuit 1
7 is controlled by the control circuit 20 and switches the infrared image signal from the infrared image sensor 16 in synchronization with the switching of the optical image by the optical switching unit 14, and the optical switching unit 14 switches the first optical system. When the optical image of the second optical system is selected, the infrared image signal is input to the first image processing section 18, and when the optical switching section 14 selects the optical image of the second optical system, the infrared image signal is input to the second image processing section 19. An infrared image signal is input.

The first and second image processing units 18 and 19 process infrared image signals inputted via the switch circuit 17, and, for example, correspond to the first optical system with a wide viewing angle. The first image processing section 18 is configured to display an image with a wide viewing angle by converting the infrared image signal into a television signal and adding it to a display device such as a CRT, and the second optical signal with a narrow viewing angle. A second image processing unit 19 corresponding to the system performs processing such as feature extraction and position detection of the target, and based on the processing results, determines whether the target is within the field of view of the first and second optical systems. In this way, a configuration can be adopted in which tracking control is performed to orient the visual axes of the first and second optical systems. In addition, vehicles or aircraft equipped with infrared imaging devices,
It is also possible to adopt a configuration in which the direction is controlled so as to track a target object.

FIG. 3 is an explanatory diagram of the operation of the embodiment of the present invention, in which (a) shows an infrared image signal from the infrared image sensor 16;
(b) shows reciprocating scanning, (c) shows unidirectional scanning, and (d
) and (e) show field-compatible infrared image signals. In this embodiment, in the case of reciprocating scanning, one reciprocating scan is performed in a time of T/2, as shown in (b), and in the case of unidirectional scanning, as shown in (c), one reciprocating scan is performed in a time of T/4, as shown in (c). The case where one scan is performed is shown below. Further, BT indicates a blanking period, which in the case of unidirectional scanning corresponds to the return period of the mirror, and in the case of reciprocating scanning, corresponds to the unstable period at the time of turning back.

The optical switching section 14 switches the mirror 21 for each T/4.
The control circuit 2 switches between the solid line position and the dotted line position.
For example, in the case of the reciprocating scan shown in FIG. 3(b), the mirror 21 is switched to the dotted line position during forward scanning, and the first optical system is controlled as shown in FIG. 3(a). The infrared image signal A1 based on the optical image is output, and during the next backward scan, the mirror 21 is switched to the solid line position, and the position shown in (a) in FIG.
), an infrared image signal B1 based on the optical image of the second optical system is output. Similarly, during the next forward scan, an infrared image signal A2 based on the optical image of the first optical system is output, and during the next backward scan, an infrared image signal B2 based on the optical image of the second optical system is output. In the case of unidirectional scanning as shown in FIG. 3(c), the optical images of the first and second optical systems are switched for each scan, so the optical images of the first and second optical systems are alternately scanned as shown in FIG. 3(a). 1, infrared image signals A1, B1, A2, B2, . . . corresponding to the optical images of the second optical system are output.

The image processing units 18 and 19 process the infrared image signal obtained at time T/4 into an infrared image signal for the field period T/2, and this process can be easily performed by using a memory or the like. can be done. Therefore,
The infrared image signal shown in (a) of FIG. 3 is (d), (e)
The infrared image signal of one frame T can be formed using two fields. In this case, if one frame T is 1/30 [sec], by scanning at twice the scanning speed of a normal television signal, as shown in FIG.
Since the infrared image signal has a field of T/2=1/60 [sec] shown in (d) and (e), the infrared image can be displayed on an ordinary television receiver. Note that the scanning direction of the infrared image signal obtained during the backward scan of the reciprocating scan is opposite to the infrared image signal obtained during the forward scan, but when displaying it on a display device, the scanning direction can be reversed using a memory etc. In the case of target object detection, detection processing can be performed even if the scanning direction is opposite.

Although the above-mentioned embodiment shows two cases in which the viewing angle is wide-angle and narrow-angle, it is also possible to provide optical systems with different viewing angles. In that case, it is necessary to increase the speed of reciprocating scanning or unidirectional scanning, but high-speed scanning becomes possible if the infrared imaging elements 16 are configured in a two-dimensional array to perform electronic scanning. Furthermore, it is also possible to display an infrared image on one display device in a split-screen or window format by combining two screens without providing two display devices, one for a wide viewing angle and one for a narrow viewing angle. Further, a display device is provided only for wide viewing angles, and infrared image signals for narrow viewing angles can be used for target tracking control processing. That is,
It is sufficient to provide one display device for observation by the operator.

[0017] Furthermore, if only one of the wide viewing angle and narrow viewing angle infrared image signals is required, the optical switching unit 1
It is possible to stop the switching operation in 4.
In that case, an infrared image signal corresponding to the field will be output twice in one field period (T/2). Therefore, the S/N ratio of the infrared image signal can be improved by averaging or adding the infrared image signal within one field period.

[0018]

As explained above, the present invention switches the optical systems 1-1 to 1-n with different viewing angles θ1 to θn in a predetermined order by the optical switching section 2, and provides optical information to the infrared imaging element 3. The image is inputted, and the infrared image signal from the infrared image sensor 3 is processed by the image processing unit 5-1 corresponding to the optical systems 1-1 to 1-n.
-5-n are switched and inputted by the switch circuit 4. Therefore, by alternately switching the first and second optical systems for different viewing angles, for example, a wide viewing angle and a narrow viewing angle, an infrared image signal with a wide viewing angle and an infrared image signal with a narrow viewing angle are transmitted in a time-division manner. The wide viewing angle infrared image signal can be added to the display device and displayed, and the target tracking control process can be performed using the narrow viewing angle infrared image signal while observing the entire object. . That is, it is possible to economically provide an infrared imaging device with multiple viewing angles.

[0019] Also, during the forward scan of the reciprocating scan, the first optical system,
By using the second optical system during backward scanning, infrared image signals with a wide viewing angle and a narrow viewing angle can be obtained. In that case,
Compared to unidirectional scanning, reciprocating scanning has the advantage that the mechanism and control of the optical system are relatively simple, and high-speed scanning is also facilitated.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention.

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

FIG. 3 is an explanatory diagram of the operation of the embodiment of the present invention.

[Explanation of symbols]

1-1~1-n Optical system 2 Optical switching section 3 Infrared imaging device 4 Switch circuit 5-1 to 5-n Image processing section θ1~θn Viewing angle

Claims (2)

[Claims] [Claim 1] Different viewing angles (θ1 to θn)
optical system (1-1 to 1-n), and the optical system (1-1 to 1-n)
-n) in a predetermined order; an infrared imaging element (3) into which the optical image switched by the optical switching unit (2) is input and outputs an infrared image signal;
The infrared image signal from the infrared image sensor (3) is switched in synchronization with the optical switching section (2), and the optical system (1-
Image processing units (5-1 to 5-n) corresponding to 1 to 1-n)
An infrared imaging device comprising: a switch circuit (4) for inputting an input to the infrared imaging device. 2. A first optical system with a wide viewing angle and a second optical system with a narrow viewing angle, and an optical image formed by the first optical system is transmitted to the infrared imaging device (
3), and the optical switching unit (2) switches so that the optical image by the second optical system is input to the infrared imaging device (3) during the backward scan of the reciprocating scan. The infrared imaging device according to claim 1.