JPS5837753B2 - Sekigaisen Anshisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an infrared night vision device for monitoring target objects at night.

In a conventional optical scanning type infrared night vision device, as shown in FIG.
The light is focused by a focusing system composed of the following, reflected by a reflecting mirror 4, and incident on the detection surface of an infrared detector 5.

The incident infrared rays are converted into electrical signals by an infrared detector 5 and amplified by a video amplifier 6, and the amplified output of the infrared rays modulates the brightness of a display cathode ray tube 9.

On the other hand, the secondary mirror 3 also serves as a scanning mirror, and is rotated at high speed by the scanning mechanism 7, vibrated in the vertical direction at a rate of, for example, once every 100 rotations, and is directed toward the rotating target object 1. While moving, the target object 1 is scanned horizontally, and vertically scanned by vibration in the elevation direction.

That is, as shown in FIG. 2A, picture elements 10 are arranged over the entire field of view 11, although only one picture element is shown in the figure, and these picture elements are sequentially scanned in the direction of the arrow to cover the field of view 11. The entire scan is completed.

Therefore, a deflection signal synchronized with the rotational vibration of the scanning mechanism section 7 is generated by a deflection signal generator 8, and these signals are applied to an XY-axis deflection coil of a display cathode ray tube 9.

Therefore, on the display cathode ray tube 9, there are
An object image 12 is displayed.

In this way, the object can be monitored by detecting the difference in the amount of infrared radiation of the target object and capturing it as an image.

The amount of infrared radiation W of an object is determined by the emissivity ε and absolute temperature T of the object, and is expressed as W-εKT' (K is Stefan Boltzmann's constant).

If the target object is not a heating element, the object is influenced by the ambient temperature and is kept at a constant temperature that is approximately the same as the ambient temperature.

When such an object is imaged using an infrared night vision device, since the temperature of the object is approximately constant, the difference in the amount of infrared radiation due to the difference in surface emissivity will be imaged.

In other words, as shown in FIG.
The difference in emissivity ε, , ε2 of each part is displayed.

When the ambient temperature surrounding the object decreases, the object temperature becomes low, and the amount of infrared radiation from the object decreases, or when the difference in emissivity of the object is small, the difference in the amount of infrared radiation is buried in the noise of the detection device. This makes projection difficult.

The purpose of the present invention is to extend the limitations of conventional such devices to a lower level, that is, to emphasize the emissivity difference or reflectance difference for objects that are cold and have a small emissivity difference, and to project infrared rays. The purpose is to provide night vision equipment.

According to the present invention, while scanning the target object, the second detector detects the infrared rays radiated from the target object as in the conventional method, and furthermore, while projecting the infrared rays toward the target object, the projection point is placed on the detection surface. It scans two-dimensionally, and its reflected infrared rays are detected by a first detector.

The projection scan of the infrared rays toward the target object is synchronized with the reception detection scan of the radiated infrared rays by the second detector, but is slightly advanced.

Therefore, the reception and detection scanning of the emitted infrared rays by the second detector sequentially scans the pixel portions of the exposed surface of the target object immediately after the infrared rays are projected from the infrared projector.

Furthermore, the polarity of one of the outputs of the first and second detectors is inverted, and the first
First and second display signals are obtained corresponding to the outputs of the detector and the second detector, respectively.

In the first aspect of the present invention, an image of the target object is optically displayed on the scanning type two-phenomenal display based on these first and second display signals.

That is, in this first invention, the display surface is scanned in synchronization with the detection scans of the first detector and the second detector, and each scanning point is optically displayed according to the first display signal and the second display signal to detect the target. The image of the object is displayed on the display screen of the scanning type two-phenomenon display.

Further, in the second aspect of the present invention, a correction circuit for correcting the phase difference between the first display signal and the second display signal is provided, and the scanning type display is performed by the first and second display signals corrected by the correction circuit. Display the image of the target object on the display screen of the device.

That is, in the second invention, the display surface of the scanning display is scanned in synchronization with the detection scan of the first detector or the detection scan of the second detector, and the phase difference is corrected at each scanning point by a correction circuit. An image of the target object is displayed on the display surface by optically displaying it in accordance with the first display signal and the second display signal.

In either method of the first or second invention, an image of the target object with enhanced contrast is displayed based on the first and second display signals.

FIG. 3 is an explanatory diagram of the operation of the present invention. When the object 15 has a portion 18 with high infrared emissivity and a portion 19 with low infrared emissivity, the picture elements 16 and 17 detected by the two detectors are The picture element 17 is shifted by one picture element in the scanning direction, and the further picture element 17
Infrared rays with a wavelength of around 10 μm, at which an object near room temperature exhibits maximum radiation, are projected onto a portion corresponding to .

In FIG. 3, horizontal and vertical scanning is performed on the detection surface, but generally, two-dimensional scanning is performed on the detection surface.

In other words, the first detector arranged corresponding to picture element 17 detects the reflected infrared rays from the object, and the second detector arranged corresponding to picture element 16 detects the reflected infrared rays from the object. Detects infrared radiation emitted from the surface of the object immediately behind it.

Immediately after infrared rays, the surface of the object absorbs the projected infrared rays, and the temperature of the parts with high absorption rate, that is, the emissivity, is high, and the temperature of the parts with low emissivity is low.

Therefore, immediately after infrared radiation is projected, areas with high emissivity have high temperatures and therefore emit a large amount of infrared rays, while areas with low emissivity have low temperatures and therefore emit a small amount of infrared rays.

Detecting the emitted infrared rays from the object detection surface immediately after the infrared rays are projected by the second detector means that the difference in emissivity of the object surface is emphasized and detected.

In this invention, the output of a first detector that detects reflected infrared rays from an object is reversed, and this is added to the output of a second detector that detects radiated infrared rays from an object immediately after infrared radiation is projected, and this is visualized.

In this way, the emissivity difference between the object surfaces is further emphasized, and radiation from low-temperature objects and small object surfaces, which was previously impossible, can be imaged, making it possible to monitor details of the object.

FIG. 4 shows an embodiment of the first infrared night vision device of the present invention, in which the infrared rays from the infrared projection device 20 are transmitted to the scanning unit 22.
The beam is scanned by a plane scanning mirror 23 in the center and projected onto the target object 21, and as shown in FIG. 3, the projection point on the detection surface of the target object 21 is sequentially scanned two-dimensionally.

The infrared ray used is a wavelength lOμ with good transmittance in the atmosphere.
It is effective to use a CO2 laser device, etc. near m.

On the other hand, the reflected infrared rays from the target object and the radiated infrared rays from the object surface immediately after the infrared projection are transmitted to the primary mirror 24 and the secondary mirror 2.
The light is focused by a light focusing system composed of 5, reflected by a reflecting mirror 26, and incident on the detection surface of a two-element detector 27.

One element of the detector 27 converts the reflected infrared rays from the object into an electrical signal, which is amplified by the video amplifier 28 and inverted by the inverter circuit 29, and then transmitted to channel 1 of the afterglow display cathode ray tube 33 with two electron guns. The electron beam of the electron gun is brightness-modulated.

The other element of the detector 27 converts the infrared radiation emitted from the surface of the object immediately after the infrared projection into an electrical signal, which is amplified by the video amplifier 30, and the electron beam of the electron gun in channel 2 of the display cathode ray tube 33 is modulated in brightness. be done.

Further, the secondary mirror 24 is rotated and vibrated by the scanning mechanism section 31 in synchronization with the plane scanning mirror 23.

A deflection signal A synchronized with this rotation and vibration and a deflection signal B whose phase is delayed by one pixel in the X-axis direction are generated by the deflection signal generator 32, and these signals A and B are channeled into the display cathode ray tube 33. It is added to XY deflection coils 1 and 2.

Therefore, on the display cathode ray tube 33, an inverted image of the image corresponding to the amount of reflection of the projected infrared rays from the object surface and an image corresponding to the amount of infrared radiation from the object surface immediately after the infrared rays are projected are combined and displayed.

In other words, the radiation image of the object's surface is emphasized and displayed.

Furthermore, if the inverter circuit 29 is connected after the video amplifier 30, it is possible to emphasize and display the reflected video on the surface of the object.

In this way, the night vision device of the present invention utilizes the reflection of the projected infrared rays from the object and the infrared radiation from the object surface immediately after the infrared rays are projected, inverts and combines either signal, and calculates the reflectance difference. , because it emphasizes the emissivity difference, it is possible to image low-temperature objects and small emissivity differences or reflectance differences that were previously impossible.

Therefore, detailed and sufficient monitoring of objects can be performed at night.

Note that it is also possible to monitor an object by projecting infrared rays and detecting only the reflected light, but compared to this case, the contrast in this device is significantly enhanced, and the effective distance to the target object is increased accordingly. The distance becomes longer;
Conversely, if the distance is the same, the infrared output can be small, and especially if it is undesirable for the target object to receive too much infrared rays, it is possible to make the infrared output small and the S/N ratio large. Become.

Note that the outputs of the two detection elements of the detector 27 may be combined directly with each other instead of on the fluorescent surface of the cathode ray tube.

Furthermore, during synthesis, it is also possible to perform correction according to the phase difference between both scans using a delay circuit, and this method corresponds to the second aspect of the present invention.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional optical scanning type infrared night vision device, FIG. 2 is an explanation diagram of its operation, FIG. 3 is an explanation diagram of the operation of the infrared night vision device of the present invention, and FIG. 1 is a block diagram showing an example of a visual device; FIG. 20: infrared projector, 21 two target objects, 22: scanning unit,
27: Detector having two detection elements, 29: Inverter, 31: Scanning mechanism section, 33: Braun tube.

Claims (1)

[Scope of Claims] 1. An infrared projector that projects infrared rays while two-dimensionally projecting and scanning its projection point onto a detection surface of a target object; a first detector that sequentially detects and scans one picture element at a time in synchronization with the projection scan of the infrared projector; and a first detector that detects and scans the detection surface of the target object at least one picture element later than the projection scan of the infrared projector. a second detector that detects infrared radiation from the detection surface; and an output of the first detector and the second detector by reversing the polarity of the output of one of the first detector and the second detector. display signal supply means for obtaining a first display signal and a second display signal respectively corresponding to the above, and scanning the display surface in synchronization with the detection scans of the first detector and the second detector, respectively, and detecting each scanning point. the first display signal and the second display signal, respectively.
An infrared night vision device comprising: a scanning type two-phenomenon display that optically displays an image of the target object on the display surface according to a display signal. 2. An infrared projector that projects infrared light while two-dimensionally scanning its projection point onto a detection surface of a target object, and synchronizing reflected infrared light from the detection surface of the target object with the projection scanning of the infrared projector. a first detector that detects the target object while sequentially detecting and scanning one pixel at a time; a second detector for detecting radiated infrared rays; and a first detector whose polarity is inverted between the outputs of one of the first and second detectors to correspond to the outputs of the first and second detectors, respectively. display signal supply means for obtaining a display signal and a second display signal; a correction circuit for correcting a phase difference between the first display signal and the second display signal; The display surface is scanned in synchronization with the detection scan, and each scanning point is optically displayed in accordance with the first display signal and the second display signal whose phase difference has been corrected by the correction circuit, thereby producing an image of the target object. and a scanning display for displaying on the display surface.