JP2005106642A - Infrared imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared imaging device, capable of presenting two or more temperature standard heat sources and further shortening of the lowering image quality of the image at temperature controlling of a temperature standard heat source. <P>SOLUTION: The infrared imaging device comprises two or more temperature standard heat sources 40 to 43 set at mutually different temperatures, established in plural and mutually different directions on the intermediate image formation plane intersecting perpendicularly with an optical axis at the intermediate image forming point position on the optical axis from the object for an imaging to an infrared detector; a collection mirror 30 moving on the intermediate image formation plane and according to the moving position, capable of reflecting the infrared images from the different temperature standard heat sources toward the infrared detector of the optical axis direction; and a sensitivity calibration means 50 for rectifying the sensitivity variations of two or more infrared detecting elements of the infrared detector, on the basis of the result of imaging two or more temperature standard heat sources with the infrared detector. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an infrared imaging device, and more particularly to an infrared imaging device using a detector composed of a plurality of infrared detection elements.

  In an infrared imaging device that uses an infrared detector composed of multiple infrared detectors, the sensitivity of each infrared detector varies, and a uniform image can be obtained even when an object of uniform temperature is shown without correction. I can't. In addition, the sensitivity variation of infrared detectors varies with time, so the sensitivity of all infrared detectors to show multiple temperature references at regular intervals in order to update the sensitivity correction data at regular or specified timings. It is necessary to have a correction mechanism.

  Conventionally, as an infrared imaging device having such a sensitivity correction mechanism, for example, there are those described in Patent Documents 1 to 4.

  The thing of patent document 1 is equipped with the 1st, 2nd heat source set to the 1st, 2nd temperature, and when the temperature of imaging object changes to the 1st, 2nd temperature vicinity, the 1st, 1st The heat information from the two heat sources is transmitted to the infrared detecting element by the heat information transmitting means, and the signal output from the infrared detecting element is corrected by receiving the heat information.

  Patent Document 2 discloses that a reference heat source is installed in a part of a scanning mirror that causes infrared rays from an imaging target to enter an infrared detector, and a plurality of filters having different light blocking properties on an optical axis connecting the reference heat source and the scanning mirror. Are sequentially inserted to correct the plurality of infrared detection elements of the infrared detector.

  Patent Document 3 discloses an infrared lens, a window that can pass light transmitted through the infrared lens, a diffusion lens that diffuses light passing therethrough, and a shutter that can be switched in an optical path, and a plurality of two-dimensional arrays. An infrared detector including an IR CCD composed of a plurality of pixels, a means for cooling the infrared detector, a control signal processing unit having means for controlling the infrared detector and processing the output signal; and An A / D converter that converts an output signal of the infrared detector output from the control signal processing unit into a digital signal, an adder / subtractor that can add or subtract an output signal of the A / D converter, and a diffusion lens of the shutter When in the optical path, the first memory that can store the signal obtained by the addition operation of the adder / subtractor, and the information of the first memory is processed and stored in the second memory as sensitivity correction data, A correction operation circuit that operates the adder / subtractor as a subtracter when photographing the outside with the shutter in the window state, and subtracts the signal of the second memory and the signal when the outside is photographed. In an infrared imaging device including a D / A converter that converts a signal into an analog signal, an infrared sensor and an infrared sensor that detect infrared light from a duplexer disposed between the shutter and the infrared detector An A / D converter that converts the above signal into a digital signal, a third memory that can store a signal detected by the infrared sensor and converted into a digital signal when the diffusing lens of the shutter is in the optical path, and an external A correction coefficient calculation circuit that calculates a correction coefficient by dividing the signal obtained by the infrared sensor when the image is taken and the signal of the third memory, and the information of the first memory And comprising a multiplier for multiplying the correction coefficient.

Patent Document 4 discloses an infrared imaging device configured to detect an infrared ray emitted from a subject and measure a thermal temperature corresponding to the infrared ray, and to switch an infrared filter for limiting the incident infrared light. A reference black body for adjusting the sensitivity of the infrared detector is disposed in the mechanism, and the sensitivity adjustment reference black body can be interposed in the infrared imaging optical path by driving the infrared filter mechanism.
Japanese Patent Laid-Open No. 9-130679 Japanese Patent Laid-Open No. 57-100436 JP-A-6-62320 JP-A-9-264794

  In an infrared imaging device, it is necessary to incorporate a temperature reference heat source for sensitivity correction in an optical system. In an infrared imaging device using a two-dimensional infrared detection element, when the sensitivity correction mechanism presents a plurality of temperature references to the two-dimensional infrared detection element, it is attached to a disk or the like into the optical path of infrared rays from the outside. The method of inserting the temperature reference heat source with an insertion mechanism is used, but if you want to have multiple temperature reference heat sources or consolidate with other correction means, the attached part such as a disc is dimensionally However, since the inertia of the driven part increases, there is a problem that a plurality of temperature references cannot be presented at high speed.

  Normally, there are two temperature reference heat sources that are controlled to +/- several degrees C above and below the typical scene temperature for two-point correction. If you need to reciprocate between distant temperatures, change the temperature reference from a high temperature scene to a low temperature scene (or from a low temperature scene to a high temperature scene). There is a problem that the image quality of the image is deteriorated during the period of several tens of seconds to several minutes until it is controlled by C.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide an infrared imaging device capable of presenting a plurality of temperature reference heat sources at high speed and further shortening image quality degradation during temperature control of the temperature reference heat source. And

The invention according to claim 1 is an infrared imaging device that captures an infrared image by inputting an infrared ray from an imaging target into an infrared detector configured by a plurality of infrared detection elements.
A plurality of temperatures provided at a plurality of different directions on the intermediate imaging plane orthogonal to the optical axis at different positions at an intermediate imaging point position in the optical axis from the imaging target to the infrared detector. A reference heat source,
A collective mirror that moves on the intermediate imaging plane and reflects infrared images from different temperature reference heat sources according to the moving position toward the infrared detector in the optical axis direction;
By having sensitivity correction means for correcting the sensitivity variation of the plurality of infrared detection elements of the infrared detector based on the result of imaging the plurality of temperature reference heat sources with the infrared detector,
The inertia of the collective mirror, which is the driven part, can be reduced, a plurality of temperature reference heat sources can be presented at high speed, and the image quality degradation during temperature control of the temperature reference heat source can be further shortened.

  According to the second aspect of the present invention, the infrared image from the plurality of temperature reference heat sources is sequentially presented to the infrared detector by including the collective mirror driving unit that drives the collective mirror to move on the intermediate imaging plane. be able to.

  In the third aspect of the invention, the plurality of temperature reference heat sources have temperature setting means for variably setting the temperature, so that it is possible to cope with a case where the representative scene temperature is changed.

In the invention according to claim 5, one or a plurality of pairs of temperature reference heat sources are provided corresponding to each of the one or more scene temperatures, and the temperature before and after the scene temperature is set in each temperature reference heat source pair. By
Even if the representative scene temperature suddenly changes greatly, the imaging image quality degradation time can be shortened.

  According to the first aspect of the present invention, the inertia of the collective mirror that is the driven part can be reduced, a plurality of temperature reference heat sources can be presented at high speed, and the image quality degradation at the time of temperature control of the temperature reference heat source can be further shortened. .

  According to the second aspect of the present invention, infrared images from a plurality of temperature reference heat sources can be sequentially presented to the infrared detector.

  Further, according to the third aspect of the invention, it is possible to cope with a case where the representative scene temperature is changed.

  According to the fifth aspect of the present invention, it is possible to shorten the imaging image quality degradation time even if the representative scene temperature is drastically changed greatly.

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

  1 and 2 are cross-sectional views of a state in which sensitivity correction is not performed and a state in which sensitivity correction is performed according to an embodiment of the infrared imaging device of the present invention. FIG. 3 is a longitudinal sectional view taken along line AA in FIG.

  In FIG. 1, an infrared lens 11 is provided at one end of the optical system barrel 10, and infrared lenses 12 and 13 are provided at the other end. Infrared rays from the object to be imaged are collected by the infrared lens 11, pass through the intermediate image forming point 14, collected again by the infrared lenses 12 and 13, and imaged and input to the two-dimensional infrared detector 15.

  A moving rail 18 is fixed at a substantially central position inside the optical system barrel 10 so as to be orthogonal to the optical axis 16 of the optical system barrel 10. As shown in FIG. 3, the moving rail 18 is provided with a rectangular opening 19. A drive and detection mechanism 20 is fixed outside the opening 19 of the moving rail 18, and a collective mirror 30 is slidably provided in the opening 19. The opening 19 serves as a guide when the collective mirror 30 moves in the directions of arrows A and B. Further, in a state where the collective mirror 30 moves in the direction of the arrow B and contacts the end face of the opening 19, that is, in a state where the sensitivity correction shown in FIG. 1 is not performed, the infrared light collected by the infrared lens 11 is the opening 19. To the infrared lens 12.

  The drive and detection mechanism 20 has, for example, a pinion (not shown) that is rotated by the drive of the motor 21, and a rack is fixed at a starting point position that contacts the drive and detection mechanism 20 at the base portion 31 of the collective mirror 30. The rack and pinion mesh with each other. For this reason, the collective mirror 30 is moved in the directions of arrows A and B by the rotational drive of the motor 21. The rotation detector 22 of the drive and detection mechanism 20 detects how much the collective mirror 30 has moved in the direction of arrow A from the starting point position by detecting the rotational position of the pinion.

  The collective mirror 30 is configured by fixing four mirrors 32, 33, 34, and 35 to the base portion 31 in a state where they are arranged in a line in the directions of arrows A and B. In FIG. 1, when the collective mirror 30 is moved in the direction of arrow A from the starting position, the mirrors 32, 33, 34, and 35 are positioned so as to pass through the intermediate imaging point 14 at the optical axis 16 position.

  Each of the mirrors 32, 33, 34, and 35 is provided with an angle of 45 ° with respect to a plane orthogonal to the optical axis 16, and the reflection direction is rotated by 90 ° about the optical axis 16 as shown in FIG. , The mirror 32 reflects light incident from above perpendicular to the paper surface in the direction of arrow A, the mirror 33 reflects light incident from above perpendicular to the paper surface in the direction of arrow C, and the mirror 34 upwards perpendicular to the paper surface. Is reflected in the direction of arrow D, and the mirror 35 is adjusted to reflect light incident from above in the direction of arrow B perpendicular to the paper surface.

  On the intermediate imaging plane, which is a plane orthogonal to the optical axis 16 at the intermediate imaging point 14 position, the temperature reference heat sources 40, 41, 41 are provided at positions where the optical axes 37, 38 orthogonal to each other intersect the optical system barrel 10. 42 and 43 are provided.

  Each of the temperature reference heat sources 40, 41, 42, 43 is housed in a space surrounded by the heat source housing 45 and the heat sink 46, and a Peltier element 47 fixed to the heat sink 46 and copper or aluminum fixed to the Peltier element 47. A temperature reference plate 48 having a good thermal conductivity such as a pneumatic, and an infrared lens 49 for condensing infrared rays emitted from the temperature reference plate 48 at the intermediate image forming point 14 are configured. The temperature reference plate 48 is set to a desired temperature by the Peltier element 47.

  For example, when controlling a typical scene temperature for two-point correction to ± 2 ° C above and below each of a low temperature scene = −7 ° C. and a high temperature scene = + 67 ° C., the temperature reference plate 48 of the temperature reference heat source 40 is The temperature reference plate 48 of the temperature reference heat source 41 is set to −5 ° C., the temperature reference plate 48 of the temperature reference heat source 42 is set to + 65 ° C., and the temperature reference plate 48 of the temperature reference heat source 43 is set to + 69 ° C. The

  As described above, in the state where the sensitivity correction shown in FIG. 1 is not performed, the collective mirror 30 is located at the start point position, that is, at a position away from the intermediate imaging point 14, and the infrared light collected by the infrared lens 11 is opened. The two-dimensional infrared detection element 10 passes through the unit 19 and reaches the infrared lens 12, and images an external subject.

  At the time of sensitivity correction, the collective mirror 30 is moved in the direction of arrow B from the starting position by the drive and detection mechanism 20, and is inserted at the position of the intermediate image point 12 as shown in FIGS. As the collective mirror 30 moves in the direction of arrow A, infrared images of the temperature reference plate 48 of the temperature reference heat sources 40, 41, 42, 43 are sequentially presented to the two-dimensional infrared detector 15. As a result, it is possible to quickly perform sensitivity correction without waiting for temperature-based temperature change and stabilization.

  FIG. 4 shows a block diagram of an embodiment of an infrared imaging device of the present invention. In the figure, the sensitivity correction control circuit 50 sets temperature data in each of the Peltier element driving circuits 51, 52, 53, 54 for driving the Peltier elements 47 of the temperature reference heat sources 40, 41, 42, 43, respectively. The temperature of the temperature reference plate 48 of each of the temperature reference heat sources 40, 41, 42, 43 is set to a desired value.

  Further, the sensitivity correction control circuit 50 controls the motor 21 of the drive and detection mechanism 20 to move the collective mirror 30 to the start position when sensitivity correction is not performed, and to move the collective mirror 30 in the direction of arrow A during sensitivity correction. The two-dimensional infrared detector 15 images the temperature reference plates 48 of the temperature reference heat sources 40, 41, 42, and 43 while detecting the movement position of the collective mirror 30 with the rotation detector 22 of the drive and detection mechanism 20. The detection temperature for each of the plurality of infrared detection elements constituting the two-dimensional infrared detector 15 is taken in, and sensitivity correction for each of the plurality of infrared detection elements is performed.

  In this way, a plurality of temperature reference heat sources are provided in a plurality of directions different from each other on the intermediate imaging plane orthogonal to the optical axis at the intermediate imaging point position in the optical axis from the imaging target to the infrared detector, and the collective mirror is provided. A set which is a driven part by moving on an intermediate imaging plane and sequentially reflecting infrared images from a plurality of temperature reference heat sources toward the infrared detector in the optical axis direction at the position of the intermediate imaging point The inertia of the mirror can be reduced, a plurality of temperature reference heat sources can be presented at high speed, and the image quality degradation during temperature control of the temperature reference heat source can be further shortened.

  Also, by providing one or more pairs of temperature reference heat sources corresponding to each of one or more scene temperatures, and setting the temperature before and after the scene temperature for each temperature reference heat source pair, the typical scene temperature drastically increases. Even if such fluctuations occur, it is possible to shorten the imaging image quality degradation time.

  In the above embodiment, the collective mirror 30 has four surfaces of the mirrors 32 to 35, and there are four corresponding temperature reference heat sources 40 to 43, but the number of mirrors and temperature reference heat sources is six or eight. You can do more. However, when forming a pair, the number of mirror surfaces and the number of temperature reference heat sources need to be a multiple of two.

The sensitivity correction control circuit 50 corresponds to the sensitivity correction means described in the claims, the drive and detection mechanism 20 corresponds to the collective mirror drive means, and the Peltier element 47 corresponds to the temperature setting means.
(Appendix 1)
In an infrared imaging device for imaging an infrared image by inputting an infrared ray from an imaging target to an infrared detector configured by a plurality of infrared detection elements,
A plurality of temperatures provided at a plurality of different directions on the intermediate imaging plane orthogonal to the optical axis at different positions at an intermediate imaging point position in the optical axis from the imaging target to the infrared detector. A reference heat source,
A collective mirror that moves on the intermediate imaging plane and reflects infrared images from different temperature reference heat sources according to the moving position toward the infrared detector in the optical axis direction;
An infrared imaging apparatus, comprising: a sensitivity correction unit that corrects sensitivity variations of the plurality of infrared detection elements of the infrared detector based on a result of imaging the plurality of temperature reference heat sources by the infrared detector.
(Appendix 2)
In the infrared imaging device according to attachment 1,
An infrared imaging apparatus, comprising: a collecting mirror driving unit that drives the collecting mirror to move on the intermediate imaging plane.
(Appendix 3)
In the infrared imaging device according to appendix 1 or 2,
The infrared imaging device, wherein the plurality of temperature reference heat sources have temperature setting means for variably setting the temperature.
(Appendix 4)
In the infrared imaging device according to attachment 3,
The plurality of temperature reference heat sources include a temperature reference plate set to a desired temperature by the temperature setting means,
An infrared imaging device comprising an infrared lens for condensing infrared rays radiated from the temperature reference plate at the intermediate imaging point position.
(Appendix 5)
In the infrared imaging device according to attachment 3,
One or more pairs of the temperature reference heat sources are provided corresponding to one or more scene temperatures, respectively, and the temperature before and after the scene temperature is set for each temperature reference heat source pair.
(Appendix 6)
In the infrared imaging device according to attachment 1,
The collective mirror has an angle of 45 ° with respect to an intermediate imaging plane, and has a plurality of mirrors arranged in a line with a reflection direction rotated by a predetermined angle around the optical axis. apparatus.

It is a cross-sectional view of a state where sensitivity correction of an embodiment of the infrared imaging device of the present invention is not performed. It is a cross-sectional view in a state where sensitivity correction is performed in an embodiment of the infrared imaging device of the present invention. It is a longitudinal cross-sectional view along the AA line of FIG. It is a block diagram of one embodiment of an infrared imaging device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical system barrel 11, 12, 13, 49 Infrared lens 14 Intermediate image point 15 Two-dimensional infrared detector 16 Optical axis 18 Moving rail 19 Opening 20 Drive and detection mechanism 21 Motor 22 Rotation detector 30 Collective mirror 31 Base Base unit 32, 33, 34, 35 Mirror 37, 38 Optical axis 40, 41, 42, 43 Temperature reference heat source 45 Heat source housing 46 Heat sink 47 Peltier element 48 Temperature reference plate 50 Sensitivity correction control circuit 51, 52, 53, 54 Peltier device drive circuit

Claims (5)

In an infrared imaging device for imaging an infrared image by inputting an infrared ray from an imaging target to an infrared detector configured by a plurality of infrared detection elements,
A plurality of temperatures provided at a plurality of different directions on the intermediate imaging plane orthogonal to the optical axis at different positions at an intermediate imaging point position in the optical axis from the imaging target to the infrared detector. A reference heat source,
A collective mirror that moves on the intermediate imaging plane and reflects infrared images from different temperature reference heat sources according to the moving position toward the infrared detector in the optical axis direction;
An infrared imaging apparatus, comprising: a sensitivity correction unit that corrects sensitivity variations of the plurality of infrared detection elements of the infrared detector based on a result of imaging the plurality of temperature reference heat sources by the infrared detector. The infrared imaging device according to claim 1,
An infrared imaging apparatus, comprising: a collecting mirror driving unit that drives the collecting mirror to move on the intermediate imaging plane. The infrared imaging device according to claim 1 or 2,
The infrared imaging device, wherein the plurality of temperature reference heat sources have temperature setting means for variably setting the temperature. The infrared imaging device according to claim 3.
The plurality of temperature reference heat sources include a temperature reference plate set to a desired temperature by the temperature setting means,
An infrared imaging device comprising an infrared lens for condensing infrared rays radiated from the temperature reference plate at the intermediate imaging point position. The infrared imaging device according to claim 3.
One or more pairs of the temperature reference heat sources are provided corresponding to one or more scene temperatures, respectively, and the temperature before and after the scene temperature is set for each temperature reference heat source pair.

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