JPS5821526A - Detecting device using infrared ray - Google Patents

Abstract

PURPOSE:To distinguish only the target having a heat source, by using two kinds of wavelength bands, and cancelling the effect of solar reflected light. CONSTITUTION:The wavelengths of incident light beams R1 and R2 are divided by a dichroic mirror M in an optical system 5. The light beam R1 having the wavelength of about 4mum is transmitted through the mirror M and inputted to a light detecting element 6. Meanwhile, the light beam having the wavelength of about 10mum is reflected and inputted to a light detecting element 7. The outputs of the light detecting elements 6 and 7 are amplified by a pre-amlifier 8, and the corresponding picture elements are subjected to subtraction in a differential amplifiers 9. At this time, each signal is adjusted to such a level that a body based on the solar reflected light disappears on a display monitor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an infrared detection device for detecting and imaging an object having a heat source.

Radar uses radio waves to detect targets flying at low altitude over the sea, but reflections from the sea surface4! ),
There are many situations that are difficult to detect. Therefore, an infrared detection device with a wavelength range of 3 to 5JIIL or S to 13μ, which can see the thermal image generated by the target, is used. However, in the case of detection using infrared rays, sunlight reflected from clouds or the sea surface throughout the day becomes an obstacle and greatly impedes detection ability.

The present invention aims to reduce the influence of sunlight and improve the ability to detect targets having heat sources.

The details of this invention will be explained below in Section 11. FIG. 1 is a block diagram showing related parts of a conventional device of this type.

In the first diagram (11 is a sensor, (2) is a rotating mount.

(4) is a signal control device, and (4) is a display monitor.

The sensor (11) basically consists of an optical system that condenses and forms an image of incident light, and a -dimensional photodetecting element array.

This is achieved by arranging the photodetector array vertically.

It covers the vertical field of view of the sensor (11).The rotating mount (21) carries the sensor (11) and rotates in the group 1 direction.

Or do back and forth exercise. The movement of the pivoting frame (2) therefore covers the lateral field of view of the sensor (11).

The signal processing device (signal processing device) scans and converts the so-called parallel scanner signals of SENNA (11) into serial video signals suitable for signal processing and display, and the zero display monitor (4) that automatically detects detection targets is operated by personnel. 9 images and other necessary information are displayed.

As mentioned above, the purpose of infrared detection equipment is to detect, for example, an aircraft flying at a low altitude, at a distance of about llllCm, and notify the personnel. Mark as shown! Not only sea level,
Clouds etc. at the same time.

Moreover, it will appear strongly and cause malfunctions to the automatic detection of this kind of leftovers.

Furthermore, even if various countermeasures are taken in consideration of the zero analogy, the target, other things, and 041 mold in signal processing, it will not be perfect.

This invention improves the above-mentioned drawbacks of the conventional ones.

Even in the above situation, by using two types of wavelength bands, it is possible to cancel the influence of reflected sunlight and to clearly distinguish only the target having a heat source.

The present invention will be explained below with reference to the drawings. FIG. 3 is a diagram qualitatively showing the spectral brightness of sunlight and a heat source target.

As can be seen from Figure 113, the sun's temperature is close to black body radiation of 600 x, so in the infrared region, the spectral brightness is high for short wavelengths. On the other hand, since the target usually has a temperature of about 3.0 to 4001, the brightness is maximum at wavelengths of about 1 to Ijm, and also at shorter wavelengths.

The brightness also decreases on the long wavelength side.

Therefore, as a photodetecting element, for example, d4μ starvation and 10711
A device with sensitivity near 1 was prepared, and the sensitivity of the two wavelength bands was adjusted so that the output difference signal would disappear on the display monitor 14), and the object reflected by the sunlight reflected from the sand and clouds would disappear. In this case, the sunlight brightness near 4μ is about 10 times higher than near 10μ, so the sensitivity on the 4# side should be 1710 degrees. Among the above wavelength bands, # is used because the transmittance of the atmosphere is high.

On the other hand, regarding the target, the brightness on the short wavelength side is 1710~1/
Since the temperature is 2011 degrees lower, the difference signal can be output without much difference from the value of the output of the photodetecting element alone, which is around 10 μm.

FIG. 4 shows only relevant parts of an embodiment of the present invention, and is a block diagram showing the internal configuration of the sensor (11).

Note that there is a rotating mount (21, signal processing device (not shown) in the same figure).
3) The 0 display monitor (4) is the same as the conventional one.

In Fig. 4, (6) is a -dimensional array 0 party detection element 1 and has an IIC sensitivity of 3 to 5μ. ()) is also an array-shaped photodetector element 2. Sensitive to m band.忤) are the respective photodetecting elements (6).

(7) A preamplifier that amplifies each output signal*, (9)
is a difference amplifier that takes the difference between corresponding pixel signals of two photodetecting elements (61, (71).

The incident light #R11R2 is also wavelength-separated by the optical system (6), which is located in the circle GIC, and the light R1 in the vicinity of 4 μm is transmitted as it is and enters the photodetector element 461K. On the other hand, 1G
#The light near the proverb is reflected and enters the photodetecting element ()). Each output of each photodetector (61, (7)) is amplified by a preamplifier (81), and the corresponding pixels are subtracted by a difference amplifier (9). Each signal is adjusted to a level such that the object disappears on the display peak (41).Also, as explained above, for this purpose, the optical system is excellent because the sensitivity on the near side of 4μ snow is good because it is low), etc. The transmittance of 10/JIL may be used as the main material.

As explained above, according to the present invention, it is possible to provide a device that can eliminate the influence of sunlight reflected from clouds, sea surfaces, etc., which are obstacles when detecting low-altitude flying objects with heat sources. .

In addition, in the embodiment, the optical system (2) was shared.

Each sensor may be an independent sensor (!1), and k may be realized by using a mirror or the like instead of a rotating mount (21) as a scanning means.

In addition, this JA A is applied in the turning direction 36 mentioned in the above explanation.
In addition to the detection device K that covers 0.00, it is also possible to apply an imaging device NIIK that uses infrared rays and is used for forward monitoring at a fixed viewing angle.

[Brief explanation of the drawing]

ν1 is a block diagram of a conventional infrared detection device, FIG. 2 is a diagram explaining its operation, FIG. 3 is a diagram explaining the present invention in detail, and FIG. 4 is a main part of the device according to this invention IIK. FIG. In the figure, 111 is a sensor, 121 is a rotating frame, (3
) is a signal processing device, (4) is a display monitor, (51 is an optical system. (61 is photodetection element 1. (71 is photodetection element 2, 181)
is a preamplifier, and (9) is a difference amplifier. In the drawings, the same or corresponding parts are designated by the same reference numerals. Single affected person 11 m Figure 2 13tjA ag

Claims (1)

[Claims] It basically consists of an optical system for condensing incident light and forming an image, a photodetecting element for photoelectrically converting the image of the formed light, and a scanning means for extracting an electrical signal as one image. In the infrared detection device, the light detection element has a wavelength of 5.
A first photodetecting element that is sensitive to any of the wavelengths in the short wavelength band below the μ value, a second photodetecting element that is sensitive to wavelengths around 10μ, and the above two types of photodetecting elements are spatially or The difference between the means for configuring the temporally identical screen and the electrical signal output from the photodetecting element of 2@ above is 3@! When the differential output increases, #IC, the side of the second photodetecting element is connected to the I! An infrared detection device characterized in that the sensitivity is made higher than that of the photodetecting element in Item 1.