CN2869893Y

CN2869893Y - Novel wave filter of eliminating optical combined change correlator zero-grade diffraction

Info

Publication number: CN2869893Y
Application number: CN 200520135484
Authority: CN
Inventors: 张勇; 冯广斌; 阎鹏程; 毛向东
Original assignee: Ordnance Technology Research Institute of General Armament Department of Chinese PLA
Current assignee: Ordnance Technology Research Institute of General Armament Department of Chinese PLA
Priority date: 2005-12-29
Filing date: 2005-12-29
Publication date: 2007-02-14
Anticipated expiration: 2015-12-29

Abstract

The utility model relates to a new type filter eliminating the zero-order diffraction of the optical joint transform correlator, aiming at the problem that zero-order diffraction spot affects the related signal detection. The utility model is constructed such that the signal input terminal of LCD panel controlled by liquid crystal driving circuit is connected with D/A converter, and the data transfer circuit of transferring filtering image data signal is connected with the signal input terminal of D/A converter through CPLD sequential simulation circuit. The utility model is characterized in that rear focus plane of optical joint transform correlactor is provided with LCD panel on which grey filtering image with grey periphery and black center is formed so as to eliminate zero-order diffraction spot and improve the diffraction efficiency and identification capability of optical joint transform correlator.

Description

A kind of new mode filter of eliminating the optical joint transform correlator Zero-order diffractive

Technical field

The utility model relates to a kind of optical device of using in optical correlation identification field, specifically a kind of new mode filter of eliminating the optical joint transform correlator Zero-order diffractive.

Background technology

Optical joint transform correlator is a kind of important optical devices in the optical correlation identification field, can be used for numerous areas such as fingerprint image identification, industrial product quality monitoring, the real-time interpretation of highest priority.It is simple in structure, is easy to realize related operation, has been widely used in realtime graphic identification field at present.But the output plane of optical joint transform correlator exists stronger Zero-order diffractive hot spot, this Zero-order diffractive hot spot greatly reduces the diffraction efficiency of correlator output, influenced detection to coherent signal, the recognition capability of optical joint transform correlator is descended, influenced detection coherent signal.

In order to eliminate the adverse effect that optical joint transform correlator output plane Zero-order diffractive hot spot is produced, the method that adopts is the methods such as frequency plane employing intermediate value, average or adaptive threshold at optical joint transform correlator mostly at present, with joint transform power spectrum binaryzation, to control the zero level spectrum of relevant output, improve the correlated performance of joint transform output plane.Concrete method adopts the hard method that stops with direct current of ending to reduce the influence of zero order of diffraction to the coherent signal of output with studying to include to the associating power spectrum, adopt phase-type SLM to eliminate the method for zero order of diffraction, and the method etc. of eliminating the zero order of diffraction of joint transform correlator based on the phase-shifting technique of the reference substance contrast inversion of input.The common ground of said method is all can only weaken the intensity of Zero-order diffractive hot spot, and can not eliminate the Zero-order diffractive hot spot.

The utility model content

The purpose of this utility model just provides a kind of new mode filter of eliminating the optical joint transform correlator Zero-order diffractive, to eliminate the Zero-order diffractive hot spot on the correlator output plane, sharpening coherent signal, the recognition capability of raising optical joint transform correlator.

The utility model is achieved in that the new mode filter of eliminating the optical joint transform correlator Zero-order diffractive is the signal input part connection D/A converter at the display panels of being controlled by liquid crystal display drive circuit, and the data transmission circuit of transmission filtered image data signal is connected to the signal input part of D/A converter through CPLD timing simulation circuit.And the signal input part of data transmission circuit and control computer are joined.

Because the Zero-order diffractive hot spot is the center that is in the optical joint transform correlator output plane, and senior diffraction peak (being real coherent signal) all departs from the output plane center, therefore, design philosophy of the present utility model is utilized data transmission circuit, CPLD timing simulation circuit and D/A converter exactly, forms the gray-scale filtering image of a peripheral burnt hair, center blackout on display panels; Display panels is placed on the back focal plane of optical joint transform correlator, like this, gray-scale filtering image on the display panels just can shelter from the zero order of diffraction of optical joint transform correlator, thereby eliminates the Zero-order diffractive hot spot on the correlator output plane.

The utility model advantage is: the one, the gray-scale filtering image that computing machine generates can be loaded on the display panels, to eliminate the Zero-order diffractive hot spot of optical joint transform correlator, the sharpening coherent signal, improved the diffraction efficiency of optical joint transform correlator thus, reduced detection influence, improved the recognition capability of optical joint transform correlator coherent signal.The 2nd, compare with the method that adopted the hard-limiting mode to eliminate the Zero-order diffractive hot spot in the past, the utility model is owing to be to adopt computer control, therefore can be at the grey scale change of input scene, adjust the gray scale area size of filtering image on the display panels in real time, to guarantee that relevant output services are in optimum condition.The 3rd, the utility model is short to the processing time of Zero-order diffractive hot spot, makes optics connection conversion correlator can carry out work under real-time mode.

Description of drawings

Fig. 1 is the circuit structure block diagram of the present utility model and the location drawing in light path.

Fig. 2 is the gray-scale filtering image that forms on display panels.

Fig. 3 is a kind of circuit structure block diagram of the data transmission circuit in the utility model.

Fig. 4, Fig. 5 are to use before and after this device, two kinds of correlated results that obtain on the joint transform correlator output plane.

Embodiment

As shown in Figure 1, the light path system of having formed optical joint transform correlator by light source, input space modulator, filtering spatial modulator, two lens and two CCD gamma cameras.

This new mode filter includes data transmission circuit 1, CPLD timing simulation circuit 2, D/A converter 3, liquid crystal display drive circuit 4 and display panels 5.Its annexation is the signal input part that is connected to D/A converter 3 by the data transmission circuit 1 of transmission filtered image data signal through CPLD timing simulation circuit 2; The signal output part of D/A converter 3 connects display panels 5; Liquid crystal display drive circuit 4 is connected on the control end of display panels 5 in the usual way.The RS232 serial ports of the signal input part of data transmission circuit 1 and control computer joins.Display panels 5 is arranged on the back focal plane in the optical joint transform correlator light path (shown in Figure 1).In this new mode filter, display panels 5 can adopt the infiltration type TFT device of bipolarity twisted liquid crystal material, and its spatial resolution is 1024 * 768, and refreshing frequency is 60Hz, and transmitance is 18%.Liquid crystal display drive circuit 4 is the custom circuit structure supporting with it, and data transmission circuit 1 and CPLD timing simulation circuit 2 also all can adopt the custom circuit overlap joint to form.

Fig. 3 has provided the circuit structure block diagram of a kind of specific implementation of data transmission circuit 1, its structure is to be core with the single-chip microcomputer, external power supply, Interrupt Process and clock, reset circuit, connect serial EEPROM storer and iic bus, and join with the CPLD of CPLD timing simulation circuit 2 simulation latch, send forbidden energy CPLD signal,, receive control computer data signals transmitted and steering order also by the MAX232 level translator.

Shown gray-scale filtering image (shown in Figure 2) on the display panels 5 in this new mode filter is is at first produced and generated by control computer.The gray-scale filtering image of computer program control is delivered among the SRAM of the single-chip microcomputer in the data transmission circuit 1 by the RS232 serial ports, after CPLD timing simulation circuit 2 receives corresponding signal, produce address signal and the chip selection signal of two SRAM successively, gray-scale filtering view data in the single-chip microcomputer that writes in advance in the data transmission circuit 1 is read, deliver to D/A converter, after digital-to-analog conversion, the final gray-scale filtering image that on display panels 5, forms a peripheral burnt hair, center blackout.Can eliminate Zero-order diffractive hot spot on the optical joint transform correlator output plane with it.

Fig. 4, Fig. 5 are to use before and after this new mode filter, the image of two kinds of correlated results that obtain respectively on the optical joint transform correlator output plane.Through contrasting as seen, to be eliminated fully in Fig. 5 at the Zero-order diffractive hot spot at Fig. 4 middle part, real coherent signal has obtained good reservation in Fig. 5.

This new mode filter utilizes control computer can also make real-time Flame Image Process.Because the scene of optical joint transform correlator input picture is complicated and changeable, the grey scale change of input picture may cause the size of Zero-order diffractive hot spot to change, therefore when input scene gray scale acute variation, by computer control, the size of real time altering filtering image gray scale area can be eliminated the Zero-order diffractive hot spot on the optical joint transform correlator output plane effectively.Make optics connection conversion correlator can under real-time mode, carry out work thus, and make relevant output services in optimum condition.

Claims

1, a kind of new mode filter of eliminating the optical joint transform correlator Zero-order diffractive, it is characterized in that this wave filter is the signal input part connection D/A converter (3) at the display panels of being controlled by liquid crystal display drive circuit (4) (5), the data transmission circuit (1) of transmission filtered image data signal is connected to the signal input part of D/A converter (3) through CPLD timing simulation circuit (2).

2, the new mode filter of elimination optical joint transform correlator Zero-order diffractive according to claim 1 is characterized in that the signal input part and the control computer of data transmission circuit (1) joined.