JPH07209075A - Infrared image pickup device - Google Patents

Abstract

PURPOSE:To provide an infrared image pickup device, which can judge largeness of the influence of infrared rays from materials except a target, for example, from the sun and which can automatically.insert and remove a wavelength limiting filter. CONSTITUTION:Largeness of the influence of the sunlight or the like is judged on the basis of the output of an infrared ray detecting element 4, and in the case where the influence of the sunlight or the like is judged to be large, a wavelength limiting filter 3 for limiting wavelength of the infrared ray, which enters the infrared rays detecting element 4, is moved into an optical path of the infrared rays, and in the case where the influence of the sunlight or the like is judged to be small, the wavelength limiting filter 3 is moved out of the optical path of the infrared rays.

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,
In particular, the present invention relates to an infrared imaging device using an infrared detection element having a sensitivity in a short wavelength range (1 to 5 μm).

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional infrared imaging device. The infrared light emitted from the target 1 is collected by the infrared optical system 2 and received by the infrared detecting element 4. The infrared detecting element 4 has sensitivity in a short wavelength region (about 1 to 5 μm). Further, a wavelength limiting filter F is arranged in the optical path between the infrared optical system 2 and the infrared detecting element 4. The wavelength limiting filter F has a wavelength range called an atmospheric window (3 to 5 μm).
This is for causing the infrared detecting element 4 to receive only infrared rays of about m). This is because in the shorter wavelength range (about 1 to 3 μm) than the wavelength range called the window of the atmosphere, the influence of sunlight is large because it is close to the visible range, and infrared rays cannot be effectively detected from the target 1. Because.

Returning to the explanation of FIG. 3, the infrared rays received by the infrared detecting element 4 are converted into electric signals, and the imaging circuit 5
Is output to. The electric signal input to the imaging circuit 5 is subjected to predetermined processing such as noise removal and then output as a TV signal to a display device or the like (not shown).

[0004]

However, in the conventional infrared image pickup device as described above, since the wavelength limiting filter F is fixedly arranged in the optical path of infrared rays, for example, in a room which is hardly affected by sunlight. In the case of photographing the target object by using the above-mentioned method, the wavelength limiting filter is not only a factor that reduces the amount of light received by the infrared detection element and reduces the S / N of the image, but is not necessary.

The present invention has been made in view of such conventional problems, and it is possible to automatically determine whether the wavelength limiting filter is inserted or removed by judging the magnitude of the influence of infrared rays from sunlight or the like. An object is to provide an infrared imaging device.

[0006]

In order to solve the above-mentioned problems, the infrared imaging device of the present invention comprises (1) an infrared detecting element 4 for detecting infrared rays and outputting an electric signal, and an infrared detecting element. An infrared optical system 2 for condensing the light, a wavelength limiting filter 3 for limiting the wavelength of the infrared rays incident on the infrared detecting element, and a wavelength limiting filter 3 between the infrared optical path and the infrared optical path. Moving means 7 for moving
The control means 6 controls the moving means 7 based on the electric signal output from the infrared detection element 4.

The infrared imaging device of the present invention is (2)
Infrared detecting element 4 for detecting infrared rays, infrared optical system 2 for focusing infrared rays on the infrared detecting element, wavelength limiting filter 3 for limiting the wavelength of infrared rays incident on the infrared detecting element, and in the infrared optical path Between the infrared ray and the outside of the optical path of infrared rays, a moving means 7 for moving the wavelength limiting filter 3, a sunlight detecting means 8 for detecting sunlight and outputting an electrical signal, and an electrical signal output by the sunlight detecting means 8. Means of transportation 7
And a control means 6 for controlling the.

[0008]

In the present invention of the above (1), it is possible to judge the magnitude of the influence of infrared rays other than the target such as sunlight by the output of the infrared detecting element 4 and control the insertion / removal of the wavelength limiting filter. Has become. For example, when the target is photographed in a room or the like where the influence of sunlight is small, since the wavelength limiting filter 3 is arranged outside the infrared optical path, the infrared detecting element 4 is used.
The amount of received light is increased, and an image with high S / N can be obtained.

Further, when the target is photographed outdoors such as when the influence of sunlight is large, the wavelength limiting filter 3 is arranged in the infrared optical path, so that the S / N ratio of which the influence of sunlight is reduced is reduced.
Higher image quality can be obtained. In the present invention (2) described above, the output of the sunlight detecting means 8 is used to determine the magnitude of the influence of sunlight, and the insertion / removal of the wavelength limiting filter is controlled.

For example, when an object is photographed in a room where the influence of sunlight is small, the wavelength limiting filter 3 is arranged outside the infrared optical path, so that the amount of light received by the infrared detecting element 4 increases. An image with high S / N can be obtained. Also,
When the target is photographed outdoors such as when the influence of sunlight is large, the wavelength limiting filter 3 is arranged in the infrared optical path, so that an image with a high S / N with reduced influence of sunlight can be obtained. You can

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first infrared image pickup device according to the present invention.
It is a principal part block diagram of an Example. The infrared rays emitted from the target 1 enter the infrared optical system 2. The infrared optical system 2 collects the incident infrared rays on the infrared detecting element 4. The infrared detection element 4 receives the collected infrared light and outputs an electric signal according to the amount of received infrared light. The electric signal output from the infrared detection element 4 is input to the imaging circuit 5. The visualization circuit 5 performs predetermined processing such as noise removal on the input electric signal and outputs it as a TV signal.

Further, the imaging circuit 5 detects that the infrared detection element 4 has saturated the output based on the electric signal output from the infrared detection element 4, and outputs a saturation signal to the control section 6. Here, the output saturation of the infrared detection element 4 means that the amount of infrared rays entering the infrared detection element is too large and the output of the infrared detection element reaches the maximum value due to the influence of infrared rays from other objects such as the sun. The output from the infrared detecting element does not change even if the amount of infrared rays from the target increases.

Returning to the description of FIG. 1, when the saturation signal is input from the imaging circuit 5, the control section 6 outputs a drive signal to the motor 7. The wavelength limiting filter 3 is connected to the motor 7. The motor 7 is rotated at a predetermined angle to move the wavelength limiting filter 3 between the infrared optical path between the infrared optical system 2 and the infrared detecting element 4 and the outside of the infrared optical path. The wavelength limiting filter 3 functions to cause only infrared rays in the wavelength range of (3 to 5) μm to enter the infrared detection element 4.

Next, the insertion / removal operation of the wavelength limiting filter 3 of the infrared image pickup device having the above-mentioned structure will be described. Now, the shooting of the target object 1 is started in an environment where the influence of sunlight or the like is large outdoors. A reset signal is input to the control unit 6 from an input device (not shown), and the control unit 6 controls the motor 7 to move the filter 3 to the outside of the infrared optical path (position B in the figure).

Infrared rays from the target 1 and infrared rays from the sun or the like are received by the infrared detecting element 4 via the infrared optical system 2. At this time, it is assumed that the infrared detection element 4 has saturated its output. The imaging circuit 5 detects that the output from the infrared detection element 4 remains unchanged at the maximum value for a predetermined time and outputs a saturation signal to the control unit 6. When the saturation signal is input, the control unit 6 outputs a drive signal to the motor 7. Motor 7
Is rotated by a predetermined angle in the direction of arrow a in the figure according to the drive signal, and the wavelength limiting filter 3 is in the infrared optical path (position A in the figure)
Move to.

When the target 1 is photographed in an environment such as indoors where the influence of sunlight or the like is small, the saturation signal is not output from the visualization circuit 5, and the drive signal from the control unit 6 to the motor 7 is also output. Is not output, the wavelength limiting filter 3 remains moving outside the infrared optical path (position B in the figure). As described above, in the present embodiment, when the infrared detection element 4 does not reach the output saturation state, that is, when the influence of sunlight or the like is small, the wavelength limiting filter 3 is moved to the outside of the infrared optical path and the target 1 is moved. Infrared detecting element 4
It is possible to obtain an image with a high S / N by increasing the amount of received light.

Further, when the infrared detecting element 4 is in an output saturated state, that is, when the influence of sunlight or the like is great, a wavelength limiting filter is inserted in the infrared optical path to have a great influence (1-2). Infrared rays having a wavelength of about μm are detected by the infrared ray detecting element 4
Since the light is not received by the infrared rays, it is possible to reduce the influence of sunlight and the like to shoot the target object 1 and prevent the output saturation of the infrared detection element 4.

In this embodiment, the output saturation of the infrared detecting element is detected to control the insertion / removal of the wavelength limiting filter. However, the imaging circuit 5 stores a predetermined threshold value in advance. Alternatively, the influence of sunlight or the like may be determined based on the result of comparison between the output of the infrared detection element and this predetermined threshold value, and the insertion / removal of the wavelength limiting filter may be controlled.

FIG. 2 is a block diagram of the main part of the infrared imaging device of the second embodiment. The parts corresponding to those in FIG. 1 are designated by the same reference numerals as those in FIG. 1 and their detailed description is omitted. Second
The infrared imaging device of the embodiment is different from that of the first embodiment in that it includes the sunlight detecting element 8 and the control unit 6 controls the motor 7 based on the output of the sunlight detecting element 8.

The sunlight detecting element 8 receives light having a wavelength of (1-2) μm, which is greatly influenced by sunlight, and outputs an electric signal corresponding to the amount of received light to the control section 6. In the embodiment, a photodiode is used. The control unit 6 determines whether or not the electric signal from the sunlight detecting element 8 exceeds a predetermined value. When the electric signal from the sunlight detecting means 8 exceeds the predetermined value, the drive signal is sent to the motor 7. Output.

The insertion / removal operation of the wavelength limiting filter of the infrared image pickup device having the above configuration will be described. Now, the shooting of the target object 1 is started in an environment where there is a lot of outdoor sunlight. When a reset signal is input to the control unit 6 from an input device (not shown), the control unit 6 controls the motor 7 to control the wavelength limiting filter 3
Is moved outside the infrared optical path (position B in the figure).

Next, the control unit 6 compares the electric signal output from the sunlight detecting element 8 with a predetermined value. When the electric signal output from the sunlight detection element 8 becomes larger than a predetermined value, the control unit 6 outputs a drive signal to the motor 7. When the drive signal is input from the control unit 6, the motor 7 rotates in the direction of the arrow a in the drawing by a predetermined angle and moves the wavelength limiting filter 3 into the infrared optical path (position A in the drawing).

When the target 1 is photographed in an environment where the influence of sunlight is small, such as indoors, the electric signal output from the sunlight detecting element 8 does not exceed a predetermined value, and the control unit 6 causes the motor 7 to operate. Since the drive signal is not output to the wavelength limiting filter 3, the wavelength limiting filter 3 remains moved outside the infrared optical path (position B in the figure). As described above, when the output level of the sunlight detecting element 8 does not exceed the predetermined threshold, that is, when it is determined that the influence of sunlight is small, the wavelength limiting filter 3 is moved to the outside of the infrared optical path. Therefore, the amount of light received by the infrared detection element 4 increases, and an image with a high S / N can be obtained.

Further, when the output level of the sunlight detecting element 8 exceeds a predetermined threshold value, that is, when it is determined that the influence of sunlight is large, the wavelength limiting filter 3 is inserted in the infrared optical path. Therefore, it is possible to capture the target 1 while reducing the influence of sunlight. In this embodiment, a photodiode is used as the sunlight detecting element, but it goes without saying that the present invention is not limited to this and various light detecting means may be used.

In the above embodiment, the wavelength limiting filter is inserted and removed between the infrared optical system and the infrared detecting element, but the wavelength limiting filter may be used between the target and the infrared optical system. The insertion / removal position of the filter is not limited to the above embodiment. Further, in the above-described embodiment, the insertion / removal of the wavelength limiting filter is determined immediately before the start of photographing the target, but it may be determined whether the wavelength limiting filter is inserted / removed during the photographing of the target.

Furthermore, in the above-mentioned embodiment, the motor is used as the moving means of the wavelength limiting filter, but it goes without saying that the present invention is not limited to this and various moving means can be adopted.

[0027]

As described above, according to the present invention of claim 1, the magnitude of the influence of sunlight or the like is judged by the output of the infrared detecting element, and when it is judged that the influence of sunlight is small, the wavelength Since the limiting filter is moved to the outside of the infrared light path, the amount of light received by the infrared detection element is increased and an image with a high S / N can be obtained.

Further, when it is determined that the influence of sunlight is large, the wavelength limiting filter is moved into the optical path of infrared rays, so that the influence of sunlight is reduced and an image with a relatively high S / N can be obtained. it can. According to the second aspect of the present invention, the magnitude of the influence of the sunlight is determined by the output of the sunlight detecting means, and when it is determined that the influence of the sunlight is small, the wavelength limiting filter is moved to the outside of the infrared optical path. Therefore, the amount of light received by the infrared detection element increases, and an image with a high S / N can be obtained.

When it is determined that the influence of sunlight is great, the wavelength limiting filter is moved into the optical path of infrared rays, so that the influence of sunlight is reduced and an image with a relatively high S / N can be obtained. it can.

[Brief description of drawings]

FIG. 1 is a configuration diagram of main parts of a first embodiment of an infrared imaging device according to the present invention.

FIG. 2 is a configuration diagram of a main part of a second embodiment of an infrared imaging device according to the present invention.

FIG. 3 is a configuration diagram of a main part of a conventional infrared imaging device.

[Explanation of symbols]

 1 Target 2 Infrared Optical System 3, F Wavelength Limiting Filter 4 Infrared Detector 5 Imaging Circuit 6 Controller 7 Motor 8 Sun Detector

Claims (2)

[Claims] 1. An infrared detection element that detects infrared rays and outputs an electric signal, an infrared optical system that focuses the infrared rays on the infrared detection element, and a wavelength of the infrared rays that enters the infrared detection element. In the infrared imaging device comprising a wavelength limiting filter for, between the inside of the infrared optical path and the outside of the infrared optical path, moving means for moving the wavelength limiting filter, and the infrared detecting element outputs An infrared imaging device comprising: a control unit that controls the moving unit based on an electric signal. 2. An infrared detection element for detecting infrared rays, an infrared optical system for condensing the infrared rays on the infrared detection element, and a wavelength limiting filter for limiting the wavelength of the infrared rays incident on the infrared detection element. In an infrared imaging device comprising: a moving unit that moves the wavelength limiting filter between an optical path of the infrared light and an optical path of the infrared light; and a sunlight that detects sunlight and outputs an electric signal. An infrared imaging device comprising: a detection unit; and a control unit that controls the moving unit based on an electric signal output by the sunlight detection unit.