CN204334777U

CN204334777U - The data acquisition circuit of Linear Array CCD Image Sensor

Info

Publication number: CN204334777U
Application number: CN201420731333.7U
Authority: CN
Inventors: 沈东�; 龙雪春; 文勋; 代先勇; 蓝常珍
Original assignee: CHENGDU PONDER TECHNOLOGY Co Ltd
Current assignee: CHENGDU PONDER TECHNOLOGY Co Ltd
Priority date: 2014-11-26
Filing date: 2014-11-26
Publication date: 2015-05-13
Anticipated expiration: 2024-11-26

Abstract

The data acquisition circuit of Linear Array CCD Image Sensor, line array CCD circuit, signal conditioning circuit, A/D change-over circuit input to single-chip microcomputer after being linked in sequence; Line array CCD circuit is using the crystal oscillator of 2.4576MHz as waveform generator, pulse is exported after 74HC74D trigger, signal conditioning circuit comprises differential amplifier, A/D converter is A/D1674, D4 mono-D11 of A/D1674 receives P0.0-P0.7 mouth of single-chip computer AT89C52 respectively, and the D0-D3 of A/D1674 receives the P0.4-P0.7 mouth of single-chip microcomputer; The data that single-chip microcomputer collects are converted to after RS232 level through MAX232 by serial ports P3.1, pass to computer.The utility model utilizes the control of single-chip microcomputer, quick sampling, storage and data processing are carried out to the output data of line array CCD, produces stable output signal, after expanding, just can be applied to one dimension size measurement, rim detection, the aspects such as interference fringe technology.

Description

The data acquisition circuit of Linear Array CCD Image Sensor

Technical field

The utility model relates to a kind of data acquisition circuit, especially the data acquisition circuit of Linear Array CCD Image Sensor.

Background technology

Charge coupled device (CCD, charge couple Device) be the novel semi-conductor imageing sensor occurred the sixties in 20th century, mainly being divided into linear array type and face formation two class, being all widely used in the aspects such as digital image-forming, satellite monitoring, fax, file scanning at present. linear CCD array is large with its measuring range, frequency response is high, real-time Transmission light-to-current inversion signal and the particular advantages such as self-scanning speed is fast and be particularly suitable for the field of precision measurement such as spectrum analysis, interferometry.CCD is using electric charge as signal, and its basic function is the generation of signal charge, storage, transmission and detection. when light incides the photosurface of CCD, first CCD completes opto-electronic conversion, namely produces the optical charge linear with incident light amount of radiation.The operation principle of CCD gathers corresponding electric charge according to the power of light, produce the weak voltage signal be directly proportional to charge quantity of light, after filtering, amplify process, export by drive circuit the vision signal that can represent the signal of telecommunication that allergen light intensity is weak or standard.Line array CCD, based on above-mentioned principle one dimensional optical information being changed into the output of telecommunications breath, realizes the function of image sensing and dimensional measurement.In the electro-optic information system being applied to CCD, first correct driving pulse must be produced, make the charge signal on each pixel of CCD gradually shift output, ensure that CCD normally works. and then the output signal of CCD is nursed one's health and AD conversion, data acquisition.For the data acquisition of ccd image sensor, require stable output signal.

Utility model content

The technical problem that the application will solve overcomes above-mentioned defect, provides a kind of data acquisition circuit of Linear Array CCD Image Sensor.

For solving the problems of the technologies described above, the technical scheme of employing is:

The data acquisition circuit of Linear Array CCD Image Sensor, line array CCD circuit, signal conditioning circuit, A/D change-over circuit input to single-chip microcomputer after being linked in sequence; Line array CCD circuit is using the crystal oscillator of 2.4576MHz as waveform generator, pulse is exported after 74HC74D trigger, signal conditioning circuit comprises differential amplifier, A/D converter is A/D1674, D4 mono-D11 of A/D1674 receives P0.O-P0.7 mouth of single-chip computer AT89C52 respectively, and the D0-D3 of A/D1674 receives the P0.4-P0.7 mouth of single-chip microcomputer; The data that single-chip microcomputer collects are converted to after RS232 level through MAX232 by serial ports P3.1, pass to computer.

The beneficial effects of the utility model are: the utility model utilizes the control of single-chip microcomputer, quick sampling, storage and data processing are carried out to the output data of line array CCD, produce stable output signal, simultaneously by data that analog to digital conversion circuit obtains, this Circuits System is by being just applied to one dimension size measurement after expansion, rim detection, the aspects such as interference fringe technology.

Accompanying drawing explanation

Fig. 1 is the circuit block diagram of this data acquisition circuit;

Fig. 2 is the signal conditioning circuit circuit diagram before A/D conversion;

Fig. 3 is A/D change-over circuit and interface microcontroller schematic diagram.

Embodiment

The data acquisition circuit of Linear Array CCD Image Sensor, line array CCD circuit, signal conditioning circuit, A/D change-over circuit input to single-chip microcomputer after being linked in sequence.Line array CCD is the TCDl251uD type of Toshiba, and this device is the two-phase linear CCD of a kind of high sensitivity, low-dark current, 2700 pixels.Operating voltage is select the crystal oscillator of 2.4576MHz as waveform generator in 12V.CCD drive circuit, crystal oscillator exports becomes the square wave that duty ratio is 1:1 after 74HC74D trigger frequency division, in order to eliminate spike, filter capacitor is added at the output of 74HC08, again because the waveform of electric capacity after filtering changes, therefore add again two inverters to make it to become standard block, the square wave now exported is duty ratio is 1:2 square wave, using it as reset pulse.Hold the count pulse of signal as three 74HCl63 heuristicimal counters of extraction from second d type flip flop Q, carry pulse is through the anti-phase PE end for being added to three 74Hcl63 after low level.

Ccd output signal being processed, mainly comprises signal condition and AD conversion two parts. the former is to eliminate various Noise and Interference as far as possible, improving picture quality, ensures that picture signal linearly changes with measured target brightness in CCD dynamic range; Latter completes the digitlization to ccd output signal, the useful signal OS that CCD exports is containing the effective photosignal through light integration, compensating signal D0S then reflects the dark current characteristic of CCD, also reflects the ideal output waveforms of capacitive interference OS and DOS that CCD Signal transmissions raceway groove under the effect of reset pulse produces, easily find out that two signals are identical by the phase place that RS capacitive is disturbed, the amplification of differential amplifier settling signal can be utilized and suppress common mode disturbances effect.

In analog-to-digital conversion part, consider required signal and incomplete ccd output signal, thus the AD1674. that the A/D converter that this design adopts is AD company of the U.S. to be produced it be a kind of 12 complete parallel-by-bit moulds, number conversion monolithic integrated circuit.This chip internal carry sampling holder, 10V reference voltage source, clock source and can and microprocessor bus direct interface temporary/tristate output buffer.The basic characteristics of AD1674 are as follows: O.125% full scale calibration error is; One pole or bipolar voltage input range are respectively 0-10V, 0-20V, ± 5V, ± 10V.Because single-chip computer AT89C52 is 8, and A/D1674 is 12, so 12/8 pin of AD1674 must ground connection make A/D become two 8 outputs, D4 mono-D11 receives P0.O-P0.7 mouth of single-chip microcomputer respectively, and D0-D3 receives the P0.4-P0.7 mouth of single-chip microcomputer; The data that single-chip microcomputer collects are converted to after Rs232 level through MAX232 by serial ports P3.1, pass to computer and carry out data processing.

Claims

1. the data acquisition circuit of Linear Array CCD Image Sensor, is characterized in that: line array CCD circuit, signal conditioning circuit, A/D change-over circuit input to single-chip microcomputer after being linked in sequence; Line array CCD circuit is using the crystal oscillator of 2.4576MHz as waveform generator, pulse is exported after 74HC74D trigger, signal conditioning circuit comprises differential amplifier, A/D converter is A/D1674, the D4-D11 of A/D1674 receives the P0.O-P0.7 mouth of single-chip computer AT89C52 respectively, and the D0-D3 of A/D1674 receives the P0.4-P0.7 mouth of single-chip microcomputer; The data that single-chip microcomputer collects are converted to after RS232 level through MAX232 by serial ports P3.1, pass to computer.