WO2003060555A1

WO2003060555A1 - Method and device for detection of optical and optoelectronic objects

Info

Publication number: WO2003060555A1
Application number: PCT/RU2002/000452
Authority: WO
Inventors: Nikolai Nikolaevich Slipchenko; Aleksandr Sergeevich Kazakov
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-27
Filing date: 2002-10-14
Publication date: 2003-07-24
Anticipated expiration: 2004-06-27
Also published as: EP1459097A1; RU2001135383A

Abstract

To reach the indicated technical result, the Method for detection of optical and optoelectronic means is applied, based on sounding of the controlled space volume by pulse or continuous emission with the spectral set, in accordance with the operating spectrum of the devices being detected, on coding of the sounding emission, e.g. by the amplitude manipulation, on the receiving of the reflected emission just in the same spectrum, on the transduction of the reflected signals into the image of the observed space volume visible for the operator visible for the operator, on the selection by the operator of the signals' images reflected from the optical and optoelectronic devices, by the fatigue influence of the flickering frequency, which is in accordance with the frequency of the amplitude manipulation of the sounding signal, while reception of the reflected signal is made from the direction, that strictly coincides with the centre of the diagram of the sounding emission of the transmitter.

Description

METHOD AND DEVICE FOR DETECTION OF OPTICAL AND OPTOELECTRONIC OBJECTS

BACKGROUND OF THE INVENTION

The invention relates to optical detection ranging, to the systems of optical search, systems for detection and recognition of type of the detected target using TV methods of signal processing.

DESCRIPTION OF THE PRIOR ART

The closest prior art is the Method for detection of optical and optoelectronic objects based on the sounding of a space volume controlled by a scanning pulse laser emission with the pulse repetition frequency of laser emission, equal to f_c/n, and on detection of optical picture signals in the spectral range of the reflected laser emission from the distance given and the section of space close to it, determined by the observation depth, on the transduction of the received signals into video signal, on the threshold selection of the set of the received video signals to eliminate the interfering background image; upon that the emitting sequence of the laser pulses is coded by the amplitude manipulation with the defined frequency, then the sequence is separated from a number of the received video signals and upon presence of the video signals, correlated with the code of the amplitude manipulation of the emitted sequence of pulses, the alarm signal is on and the fatigue flickering of brightness of the screen with the frequency of the amplitude manipulation is fixed by the help of an operator (Patent RU JV° 2133485).

This Method has got a drawback. The maximum level of the reflected signal does not coincide with the direction of the reception axis due to the parallax between the direction of the sounding signal and the direction of the reception axis of the emission reflected from an object at the nearest zone (at the small distances from the detected objects).

This is explained by the narrow diagram of the reflected signal, which is characteristic of the cat's eye systems, for instance, the optical systems with reflecting elements close to their focus (a TV- camera with objective, a sight with grid etc.).

The technical result of the invention developed is the increased probability of detection of optical and optoelectronic objects (for instance, TV-cameras), which are at the nearest zone.

To reach the indicated technical result a Method for detection of optical means and means of optoelectronic type is proposed, that is based on sounding of the controlled space volume by pulse or continuous emission with the spectral set in accordance with operating spectrum of the detected objects, on coding of the sounding emission, e.g. by the amplitude manipulation, on receiving of the reflected emission in the same type of spectrum, on transduction of the reflected signals into a visible for operator image of the observed space volume, on selection by an operator of the signals' images reflected from the optical and optoelectronic devices by fatigue influence of the frequency of flickering, which is in accordance with the frequency of the amplitude manipulation of the sounding signal; while reception of the reflected signal is carried out from the direction, which strictly coincides with the center of the diagram of the sounding emission of the transmitter.

The closest analogue of the applied Device is the Device for detection of optoelectronic objects, comprising the frequency-pulse laser, the image converter tube with objective, the photoreceiving unit, the videocontrol unit, the videosignal processing unit, the synchronizer, two high voltage pulse sources, the block of lock pulses, the key-board, the frame frequency divider, the modulator, the automatic grain control (Patent RU M> 2129287).

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and features of the present invention will now be described in greater detail with reference to an exemplary embodiment, which is intended to explain and not to limit the invention, and is illustrated in the drawings, that is FIGURES 1 and 2 show the indicated Method can be realized by the Device. DESCRIPTION OF THE PREFERRED EMBODIMENT

The technical result is the increase of probability of the detection of optical and optoelectronic objects at the nearest zone, and it is reached by the installed semi-transparent mirror (2), the absorber (3) and conditions of installation of the above-mentioned elements, by alignment of the optical axes of lasers and TV-camera in the sounding space volume, by utilization of laser (8) emission, which does not coincide with the direction of the optical axe of TV-camera (4).

The Device to realize the Method for detection of optoelectronic objects consists of the plane semi-transparent mirror (2), the emission absorber (3), the receiver as the TV-camera with objective (4), the monitor (5), the frame frequency divider (6), the transmitter [the laser or any other source of light with objective] (8), the modulator (7).

The Device operates in the following way. The videosignal from TV-camera (4) gets to the monitor (5). The frame frequency gets from the TV-camera (4) to the frame frequency divider (6), which is linked with the modulator (7). The modulation signal from the modulator (7) comes at the laser (8). The laser emission, modulated by the frequency f_k/n, where f is the frame frequency of the TV-camera (4), n is a number equal to 10-12, and it should be in the range of 3-5 Hz (the indicated value of the frequency is good for human viewing), gets at the object (1) reflecting from it, while the maximum of the reflected emission (10) coincides with the direction of the emission (9) reducing.

3AMEHflI0mHH JIHCT The optical axes of the laser (8) and the TV-camera (4) are aligned at the right angle, and the semi-transparent mirror is set at crossing of their optical axes at the angle of 45°. The indicated alignment of the laser (8) and the TV-camera (4) provides full coincidence of their optical axes at the sounding space volume.

The absorber (3) of the emission, which goes through the mirror (2), is set at a distance from the semi-transparent mirror (2). As the absorber an absolutely black body or a polished glass plate made from glass of HC grade can be used, set parallel to the semi- transparent mirror (3) in such a way, so that to cover all the aperture of the laser (5) emission and not to vignette the objective of the TV-camera.

The reflected emission is shown at the monitor screen (5) as a characteristic bright and flickering point, due to it operator detects an optoelectronic object, which has got into the field of view of the device.

The emission reflected from the detected optoelectronic device has a very narrow diagram and coincides by its direction with the axis of the reducing emission; the reached coincidence of the optical axes of the transmitter and the receiver [installation of the semi-transparent mirror (2) increases the level of the signal being received (detected) up to its maximum actually], so that it increases possibility of detection or potential of the Device; it is especially important for the nearest zone, when due to the mutual parallax of objectives of the transmitter and the receiver only a part of the reflected emission can get into the objective of the receiver, that considerably reduces probability of detection of optoelectronic and optical devices.

Presence of the element, absorbing the unused emission (the absorber (3) of emission) excludes reception of objects' images from other directions, as well as it excludes illumination of the TV-camera by emission, that has come through the semi-transparent mirror (2).

Instead of the semi-transparent mirror (2) a glass plane-parallel plate can be installed in the same position; an opaque mirror coating, covering the aperture of the laser emission, is put on at the centre of the butt-end of the plate, which faces with the side of the sounding space volume.

There is the variant of the applied Device, which contains the transmitter (8), incorporated at the centre of the receiver's objective (4) (see FIG.2).

Claims

1. The Method for detection of optical and optoelectronic objects, based on sounding of the controlled space volume by the pulse or continuous emission with the spectral set, according the operating range of the devices being detected, on coding of the sounding emission by the amplitude manipulation, on receiving of the reflected emission in the same spectrum, on the transduction of the reflected signals into a visible for operator image of the observed space volume, on selection of the image of the signals by an operator, which are reflected from optical and optoelectronic devices by the fatigue influence of the flickering frequency, which is in accordance with the frequency of the amplitude manipulation of the sounding signal, differing by that reception of the sounding signal reflected from the object is carried out at the direction that strictly coincides with the centre of the diagram of the sounding emission of the transmitter.

2. The Device for detection of optical and optoelectronic objects in the nearest zone, comprises the TV-camera with objective, linked to the monitor, the laser or any other collimated source of light, the input of which is linked with the second output of the TV-camera through the modulator and the frame frequency divider f_k/n, differing by that the semi-transparent mirror and the emission absorber are used in; for instance, the neutral filter of big density, the TV-camera and the laser are set, so that their optical axes make the direct angle, the semi-transparent mirror is set at crossing of optical axes of the TV-camera and the laser at the angle of 45° with the optical axis of the laser, while the reflecting coating of the semi-transparent mirror is faced to the sounding space volume, the energy absorber is set parallel to the semi-transparent mirror on centre of the optical laser axis, without the aperture of the objective of the TV-camera.

3. The Device, according to item 2, that does not include the energy absorber, but instead of the semi-transparent mirror the glass plane- parallel plate is just set in the same position, the opaque mirror covering, that overlaps the aperture of the laser emission, is put on at the centre of the butt-end of the plate, which is faced to the sounding space volume.