JP2851011B2 - Failure detection device for infrared imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a failure detection device that checks and determines the operation state of a portion related to the reception sensitivity of an infrared imaging device, and determines whether or not the imaging device has failed even in a system without a video display unit. For the purpose of making it easy to determine, the temperature detection means for detecting the ambient temperature of the infrared detection means and the output voltage allowable width of the temperature-output voltage characteristic when the infrared detection means is operating normally are set in advance. Failure detecting means for detecting whether or not there is a failure based on whether or not the output voltage of the infrared detecting means is within an allowable output voltage range for the detected temperature when the temperature is detected by the temperature detecting means; Is provided.

[Industrial applications]

The present invention relates to a failure detection device that checks and determines an operation state of a portion related to reception sensitivity of an infrared imaging device.

2. Description of the Related Art There is known a system that monitors an object using an infrared imaging device and detects an abnormality of the object, and a target mounted on an aircraft, a ship, a missile, or the like. In this case, it is necessary that the portion related to the receiving sensitivity of the infrared imaging device is operating normally in order to perform these detections correctly. If a failure occurs in this portion, it is quickly detected. It is necessary to take appropriate measures.

[Conventional technology]

FIG. 4 shows a block diagram of an example of the prior art. In the figure, incident light (infrared light) is condensed by an optical
It is photoelectrically converted by the infrared detector 2 including D and the like. At this time, the infrared detector 2 is cooled to about -200 ° C. by the cooler 3 so as to maintain a predetermined operation state. The output of the infrared detector 2 is converted into a digital signal by the AD converter 4 and sent to a display or a computer. When the monitored object has an abnormal temperature, for example, it is detected by the infrared detector 2 and displayed on a display, or is analyzed by a computer.

[Problems to be solved by the invention]

Conventionally, whether or not the infrared imaging device is operating normally, visually confirm the image on the display,
For example, the cooling temperature of the cooler 3 is checked. However, the image on the display (contrast related to the receiving sensitivity, etc.) is affected by the monitored object and weather conditions, and varies depending on human subjectivity, and it is accurately determined whether or not the original system performance is obtained. There was a problem that was difficult to do. In addition, when used in a system for guiding an object, a display is not provided since it is not necessary. Therefore, in such a system, an image on the display cannot be confirmed, so that the operation state is checked. There was a problem that could not be done.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a failure detection device for an infrared imaging device that can easily determine the presence or absence of a failure in an imaging device even in a system without a video display unit.

[Means for solving the problem]

FIG. 1 shows a principle diagram of the present invention. In the figure, reference numeral 11 denotes a temperature detecting means for detecting the environmental temperature of the infrared detecting means. Reference numeral 12 denotes a failure detection means, which is an allowable output voltage width (△ S ₁ ,
ΔS ₂ ,...) Are stored in advance, and when the temperature (T ₁ ) is detected by the temperature detecting means 11, the output voltage of the infrared detecting means 10 is set to an allowable output voltage for the detected temperature (T ₁ ). The presence or absence of a failure is detected based on whether or not it is within the width (△ S ₁ ).

[Action]

In the present invention, in the failure detecting means 12, the output voltage allowable range when the infrared detecting means 10 is operating normally is set in advance, so that if the output voltage of the infrared detecting means 10 falls within the allowable range, it is normal. Can be detected, and if it does not fall within the allowable range, a failure can be detected. In this case, since the judgment is not made by looking at the image on the display, the present invention can be applied to a system having no display and can be accurately detected.

〔Example〕

FIG. 2 is a block diagram of one embodiment of the present invention. In FIG. 2, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 2, reference numeral 5 denotes a receiving window cover, which is provided on the front surface of the optical system unit 1. Reference numeral 6 denotes a temperature detector for detecting an environmental temperature (temperature of a lens barrel or the like) near the optical system 1.
Numeral 7 denotes a computing unit, which is composed of a window-type comparator. The window widths ΔS ₁ , ΔS ₂ , with respect to the environmental temperatures T ₁ , T ₂ ,. …
(Described later) are programmed in advance.

Here, the relationship of the output voltage to the incident light power (proportional to the environmental temperature) of the infrared detector 2 is as shown in FIG. 3, and the output voltage increases as the incident light power increases.
Now, the incident light that has entered through the receiving window cover 5 is condensed by the optical system unit 1 and photoelectrically converted by the infrared detector 2.
Further, the signal is converted into a digital signal (voltage) by the AD converter 4 and supplied to the arithmetic unit 7. On the other hand, the environmental temperature is detected by the temperature detector 6 and supplied to the calculation unit 7.

Here it will be described a case temperature detected by the temperature detector 6 was T _1. The arithmetic unit 7, the programming window width of the foregoing, the output of the AD converter 4 when the temperature T ₁ of fall within the scope device is a window width △ S ₁ shown in FIG. 3 as long as they are operating normally If the output of the AD converter 4 is the voltage _ST1 shown in FIG. 3, it is detected that the imaging device is normal, and GO is detected.
Can output a detection signal, whereas, if any part (optical system unit 1 of the image pickup device if the voltage output of the AD converter 4 is out of the window width △ S _1, the infrared detector 2, the AD converter 4 ) Can detect a failure and output a NO GO detection signal. In this case, it is assumed that the cooler 3 is operating normally and the infrared detector 2 is given a predetermined operating temperature.

As described above, the window width for setting the environmental temperature when the apparatus is operating normally is set in the arithmetic unit 7, and whether the output of the AD converter 4 falls within the set window width is determined. Whether or not a failure has occurred in the imaging device can be detected based on whether or not the failure has occurred. In this case, failures can be detected without checking the display, so it can be applied to systems that do not have a display. Can be detected.

In the case of an imaging apparatus in which the receiving window cover 5 cannot be set, the focus is set to the nearest point while the visual axis of the apparatus is horizontal and an image of a distant target is taken, or an image of an extremely close target is taken. In such a state, the focal point is set to infinity, that is, blur is intentionally caused, and the incident light averaged with respect to the ambient temperature is taken in.

[Configuration of the invention]

As described above, according to the present invention, the presence or absence of a failure is detected by determining whether or not the output voltage of the infrared detection means falls within a preset output voltage allowable range. Can be detected accurately and can be applied to a system without a display.

[Brief description of the drawings]

 1 is a principle diagram of the present invention, FIG. 2 is a block diagram of one embodiment of the present invention, FIG. 3 is an input / output characteristic diagram of an infrared detector, and FIG. In the figure, 1 is an optical system unit, 2 is an infrared detector, 4 is an AD converter, 5 is a receiving window cover, 6 is a temperature detector, 7 is an arithmetic unit, 10 is infrared detecting means, 11 is temperature detecting means, Reference numeral 12 denotes a failure detection means.

Claims (1)

(57) [Claims] A temperature detecting means for detecting an environmental temperature of an infrared detecting means, and an output voltage tolerance of a temperature-output voltage characteristic when the infrared detecting means is operating normally. The widths (△ S ₁ , ΔS ₂ ,...) Are stored in advance, and when the temperature (T ₁ ) is detected by the temperature detecting means (11), the output voltage of the infrared detecting means (10) is output voltage tolerance for the detected temperature (T ₁₎ (△ S ₁₎ infrared imaging apparatus characterized by comprising providing a fault detection means (12) for detecting the presence or absence of a failure based on whether or not in the Failure detection device.