CN103033818A - Anti-cloud-disturbance laser detection device - Google Patents

Abstract

The invention discloses a cloud and fog interference laser detection device, which relates to the technical field of laser detection devices. It includes a transmitting unit, a receiving unit and a timing pulse generator. The transmitting unit includes a horizontally polarized pulsed laser generator, a vertically polarized pulsed laser generator and a transmitting optical system; the receiving unit includes a receiving optical system, a vertically polarized filter, a photodetector, Receive amplifying channel, peak detection circuit and threshold comparator. The device can reduce the interference of clouds and fog. When there is cloud and fog interference, there is no output signal, and when there is no cloud and fog interference, the target trigger signal is output, which improves the accuracy of detection.

Description

An anti-cloud and fog interference laser detection device

technical field

The invention relates to the technical field of laser detection devices, in particular to a cloud and fog interference-resistant laser detection device.

Background technique

Because the laser is in the infrared frequency band, clouds and fog can cause strong scattering and attenuation of the laser signal. Therefore, in the cloud environment, the infrared light forms multiple scattering among the cloud and water particles, and the echo signal received by the laser detection device not only has the interference signal formed by the cloud multiple scattering; wave signal. In order to realize the environmental adaptability of the laser detection device, it is necessary to adopt the necessary anti-cloud and fog interference technology.

Clouds and artificial targets have different light reflection characteristics. Because the water in the cloud exists in the form of particles, when the polarized light hits the cloud and generates reflection, it will cause a change in the polarization characteristics of the polarized light, that is, there is a serious "depolarization" phenomenon in the reflection of the cloud; It is a regular surface, and there is basically no "depolarization" phenomenon. Utilizing the different reflection characteristics of polarized light between clouds and artificial targets, an effective anti-cloud and fog interference system can be formed.

Contents of the invention

The technical problem to be solved by the present invention is to provide an anti-cloud and fog interference laser detection device, which can reduce the cloud and fog interference and improve the detection accuracy.

In order to solve the above technical problems, the technical solution adopted by the present invention is: an anti-cloud interference laser detection device, which is characterized in that it includes:

The timing pulse generator is used to control the timing of the horizontally polarized pulse laser generator, the vertically polarized pulse laser generator, the peak detector and the threshold comparator, and is used to generate a sequence of emission pulse signals including at least two specific time intervals, by changing The pulse amplitude relationship before and after the time interval adjustment of the pulse signal sequence;

Launch unit:

The horizontally polarized pulse laser generator continuously emits horizontally polarized pulse signals at specific time intervals;

The vertically polarized pulse laser generator continuously emits vertically polarized pulse signals at specific time intervals;

The emission optical system is used to form the generated horizontal and vertical polarized pulse signals into a specific emission beam shape according to the application characteristics;

Receiver unit:

a receiving optical system for receiving transmitted signals reflected by objects in a specific space area;

Polarization filter, used for filtering, attenuating the amplitude of horizontally or vertically polarized pulse signals, and the corresponding vertically or horizontally polarized pulse signals are not attenuated;

A photodetector for converting the light pulse signal into an electrical pulse signal;

The receiving amplification channel is used to amplify and process the electric pulse signal and transmit it to the peak detector and threshold comparator;

The peak detector is used to realize the amplitude detection and maintenance of the electric pulse signal, and its output is used as the threshold input of the threshold comparator, and the pulse signal amplitude maintained by the peak detector circuit in the time series is used as the comparison threshold of the subsequent signal;

The threshold comparator is used to compare the horizontally polarized pulse signal and the vertically polarized pulse signal at a specific time interval, and select whether to output the target trigger signal according to the actual value.

Preferably: the polarizing filter is a horizontal polarizing filter or a vertical polarizing filter.

The beneficial effect produced by adopting the above-mentioned technical scheme is that: the device utilizes clouds and artificial targets to reflect different characteristics of polarized light, and the transmitting unit is designed to continuously transmit horizontally polarized light signals and vertically polarized light signals according to specific time intervals, and the receiving unit optically The design adopts vertical polarizing filter or horizontal polarizing filter, the vertical polarizing filter attenuates the horizontally polarized optical signal, while the vertically polarized optical signal passes through without loss, the horizontal polarizing filter attenuates the vertically polarized optical signal, and the horizontally polarized optical signal pass without loss. When using a vertically polarizing filter, first send a horizontally polarized light signal, then send a vertically polarized light signal, when using a horizontally polarized light filter, first send a vertically polarized light signal, and then send a horizontally polarized light signal. Take the receiving unit of the device using a vertical polarizing filter as an example. When there is no cloud and fog, the polarization state of the reflected light of the artificial target remains unchanged. After being filtered by the vertical polarizing filter, the amplitude of the first optical pulse signal attenuates, and the second There is no attenuation of the optical pulse signal, and the amplitude difference between the front and rear signals is very large. When there is cloud and fog, the reflected light signal of the cloud and fog appears depolarized, no matter whether the emitted light is horizontally polarized or vertically polarized, the reflected light is close to unpolarized light; after being filtered by the vertical polarizing filter, the amplitude of the two pulse signals is close, and it is judged as Cloud and fog interference, no output signal; when the amplitude of the first optical pulse is much lower than the amplitude of the second optical pulse, it is judged as the target signal, and the threshold comparator outputs the target trigger signal. Therefore, the device can reduce the interference of clouds and fog, and when there is cloud and fog interference, there is no output signal, and when there is no cloud and fog interference, it outputs a target trigger signal, thereby improving the accuracy of detection.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a block diagram of the present invention;

Fig. 2 is a schematic diagram of the time sequence of the horizontally polarized transmitting signal of the present invention;

Fig. 3 is a schematic diagram of the timing sequence of vertically polarized transmitting signals of the present invention;

Fig. 4 is the timing diagram of the received signal without cloud and fog echo of the present invention;

Fig. 5 is a timing schematic diagram of a received signal without target echo in the present invention;

Fig. 6 is a timing diagram of the input signal of the threshold comparator of the present invention;

FIG. 7 is a timing diagram of the output signal of the threshold comparator of the present invention.

Detailed ways

As shown in Figure 1, take the polarizing filter as a vertical polarizing filter as an example. An anti-cloud and fog interference laser detection device includes a transmitting unit, a receiving unit and a timing pulse generator. The timing pulse generator is used to control the timing of the horizontally polarized pulsed laser generator, the vertically polarized pulsed laser generator, the peak detector and the threshold comparator, thereby realizing the timing control of the whole machine of the device, and can also be used to generate at least Two specific time intervals of transmitting pulse signal sequences, by changing the time interval of the pulse signal sequence to adjust the relationship between the pulse amplitude before and after.

The transmitting unit includes a horizontally polarized pulsed laser generator, a vertically polarized pulsed laser generator and a transmitting optical system; the horizontally polarized pulsed laser generator emits horizontally polarized pulsed signals according to the control timing; the vertically polarized pulsed laser generator emits vertically polarized pulsed signals according to the controlled timing Pulse signal; the transmitting optical system is used to form the generated horizontally and vertically polarized pulsed light signal into a specific transmitting beam shape according to the application characteristics.

The receiving unit includes a receiving optical system, a vertical polarization filter, a light detector, a receiving amplification channel, a peak detection circuit and a threshold comparator. The receiving optical system is used to receive the transmitted signal reflected by the object in a specific space area; the vertical polarization filter is used for filtering and attenuating the amplitude of the horizontally polarized pulse signal, and the vertically polarized pulse signal has no attenuation; the optical detector is used It is used to convert the optical pulse signal into an electrical pulse signal; the receiving amplification channel is used to amplify the electrical pulse signal and transmit it to the peak detector and threshold comparator; the peak detector is used to realize the amplitude detection and hold of the electrical pulse signal, and the peak value The detection circuit maintains the amplitude of the preceding pulse signal in the time series as the comparison threshold of the subsequent signal; the threshold comparator is used to compare the amplitude of the pulse signal before and after, and select whether to output the target trigger signal according to the actual value.

As shown in Figures 2-7, the timing logic diagram of the present invention, the device utilizes clouds and artificial targets to have different reflection characteristics of polarized light, and the transmitting unit is designed to continuously transmit horizontally polarized light signals and vertically polarized light signals according to specific time intervals, The optical design of the receiving unit adopts a vertical polarizing filter, which attenuates the horizontally polarized light signal, while the vertically polarized light signal passes through without loss. When there is no cloud and fog, the polarization state of the reflected light of the artificial target remains unchanged. After being filtered by the vertical polarization filter, the amplitude of the first optical pulse signal is attenuated, and the signal amplitude of the second optical pulse is not attenuated. The amplitude difference between the front and rear signals is very large.

When the polarizing filter is a horizontal polarizing filter, the function of the device can be realized in principle by only needing to adapt to launching a vertically polarized signal first and then emitting a horizontally polarized signal; the device can adopt a change timing pulse generator The sent pulse time interval is adjusted according to the relationship between the front and rear pulse amplitudes.

When there is cloud and fog, the reflected light signal of the cloud and fog appears depolarized, no matter whether the emitted light is horizontally polarized or vertically polarized, the reflected light is close to unpolarized light; after being filtered by the vertical polarizing filter, the amplitude of the two pulse signals is close, and it is judged as Cloud and fog interference, no output signal; when the amplitude of the first optical pulse is much lower than the amplitude of the second optical pulse, it is judged as the target signal, and the threshold comparator outputs the target trigger signal. Therefore, the device can reduce the interference of clouds and fog, and when there is cloud and fog interference, there is no output signal, and when there is no cloud and fog interference, it outputs a target trigger signal, thereby improving the accuracy of detection.

In this paper, specific examples are used to illustrate the principle of the present invention and its implementation. The description of the above embodiments is only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (2)

1. An anti-cloud and mist interference laser detection device is characterized in that, comprising: The timing pulse generator is used to control the timing of the horizontally polarized pulse laser generator, the vertically polarized pulse laser generator, the peak detector and the threshold comparator, and is used to generate a sequence of emission pulse signals including at least two specific time intervals, by changing The pulse amplitude relationship before and after the time interval adjustment of the pulse signal sequence; Launch unit: The horizontally polarized pulse laser generator continuously emits horizontally polarized pulse signals at specific time intervals; The vertically polarized pulse laser generator continuously emits vertically polarized pulse signals at specific time intervals; The emission optical system is used to form the generated horizontal and vertical polarized pulse signals into a specific emission beam shape according to the application characteristics; Receiver unit: a receiving optical system for receiving transmitted signals reflected by objects in a specific space area; Polarization filter, used for filtering, attenuating the amplitude of horizontally or vertically polarized pulse signals, and the corresponding vertically or horizontally polarized pulse signals are not attenuated; A photodetector for converting the light pulse signal into an electrical pulse signal; The receiving amplification channel is used to amplify and process the electric pulse signal and transmit it to the peak detector and threshold comparator; The peak detector is used to realize the amplitude detection and maintenance of the electric pulse signal, and its output is used as the threshold input of the threshold comparator, and the pulse signal amplitude maintained by the peak detector circuit in the time series is used as the comparison threshold of the subsequent signal; The threshold comparator is used to compare the horizontally polarized pulse signal and the vertically polarized pulse signal at a specific time interval, and select whether to output the target trigger signal according to the actual value. 2. A kind of anti-cloud interference laser detection device according to claim 1, characterized in that said polarizing filter is a horizontal polarizing filter or a vertical polarizing filter.

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