Pixel data reading method and reading circuit suitable for flat panel detector
A technology of flat panel detector and pixel data, which is applied in medical X-ray detection. field, it can solve the problems of slow conversion speed and the inability to increase the number of ADCs without limit, and achieve the effects of increased transmission speed, performance improvement, and fast readout speed
Inactive Publication Date: 2018-01-30
北京海思威科技有限公司
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[0002] In the existing amorphous silicon flat panel detector, the row and column gating circuit sequentially couples the charge accumulated on each pixel to the sample and hold circuit and converts it into a digital signal by the ADC. In order to obtain a sufficiently high measurement accuracy, the ADC needs to have a sufficiently high bit The main types of existing ADCs include integral type, successive approximation type, parallel comparison type / serial parallel type, Σ-Δ modulation type, capacitor array successive comparison type and voltage-frequency conversion. High-digit ADCs not only have slower conversion speeds, but also These two factors limit the readout speed of high-precision flat-panel detectors. Although increasing the number of ADCs and data transmission buses can also increase the overall readout speed, due to cost and space Due to the limitation of system complexity, the number of ADCs cannot be increased without limit
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[0031] The main hardware components of the present invention are as Figure 1-3 As shown, including sample and hold circuit, differential amplifier circuit, ADC, DAC and FPGA, the voltage signal coupled by the gating circuit passes through V in The terminal is connected to the sample-and-hold circuit, and the held voltage signal is differentiated through the differential amplifier and the reference voltage output by the DAC (digital-to-analog converter); the differential result is sent to the ADC (analog-to-digital converter) for conversion into a digital signal, and the digital signal is obtained by The FPGA (Field Programmable Gate Array) reads in and sends it to the data interface for external transmission. At the same time, the FPGA calculates the absolute value of the input signal according to the set value of the DAC and the read-in value of the ADC, stores the absolute value, and In the corresponding differential operation, after being converted into an analog signal by...
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The present invention relates to a method for reading pixel data suitable for flat panel detectors and a circuit for reading pixel data using the method. For the corresponding difference value, perform modulus conversion on the difference value, and output the difference value data or the corresponding absolute value data obtained by calculation as the data of the current pixel. The circuit comprises a sample and hold circuit, a differential amplifier circuit, ADC, DAC and a programmable controller, one input of the differential amplifier is connected to the output signal of the sample and hold circuit, and the other input is connected to the output signal of the DAC , the input end of the ADC is connected to the differential signal output by the differential amplifier. The invention can use the ADC with a smaller number of digits to complete high-precision readout and reduce the bandwidth requirement of data transmission with the same quality, and is mainly used for pixel data reading of amorphous silicon flat panel detectors and other suitable flat panel detectors.
Description
technical field [0001] The invention relates to a pixel data reading method suitable for flat panel detectors and a corresponding data reading circuit, mainly used for pixel data reading of amorphous silicon flat panel detectors and other suitable flat panel detectors, especially medical X-ray detection. Background technique [0002] In the existing amorphous silicon flat panel detector, the row and column gating circuit sequentially couples the charge accumulated on each pixel to the sample and hold circuit and converts it into a digital signal by the ADC. In order to obtain a sufficiently high measurement accuracy, the ADC needs to have a sufficiently high bit The main types of existing ADCs include integral type, successive approximation type, parallel comparison type / serial parallel type, Σ-Δ modulation type, capacitor array successive comparison type and voltage-frequency conversion. High-digit ADCs not only have slower conversion speeds, but also These two factors lim...
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IPC IPC(8): H03M1/54
Inventor 曹文田皱宇斌
Owner 北京海思威科技有限公司