Flat panel detector with automatic exposure control function and control method

Abstract

The invention discloses a flat panel detector with an automatic exposure control function and a control method. The flat panel detector comprises a first light conversion layer, a first light sensor,a first scanning reading chip, and an acquisition control assembly for automatic exposure control. The control method comprises the following steps of: a, before exposure is started, DAEC activation pixels and a target gray value V are set, an exposure switch is turned, and exposure is started; b, a DAEC layer rapidly and uninterruptedly scans repeatedly to read out the gray values of M*N pixels,the average gray value of the DAEC activated pixels is calculated each time the scanning is carried out, and all the average values are accumulated; and c, when the accumulated sum is larger than or equal to the set target value V, a high-voltage generator stops exposure, and automatic exposure control is completed. The scanning and reading time of the acquisition control assembly can be improved,and high-speed, stable and accurate response of the DAEC is realized.

Description

technical field [0001] The invention relates to the imaging field of X-ray detectors, in particular to a flat panel detector with automatic exposure control function and a control method. Background technique [0002] Automatic exposure control (AEC) technology is widely used in X-ray imaging systems. Its basic principle is based on the image quality reaching the level required for clinical diagnosis, and setting the corresponding dose threshold to control the end of exposure. At present, there are mainly two implementation methods, namely the sensor (ionization chamber) dose detection method and the secondary exposure method. [0003] Ionization chamber dosimetry uses devices such as ionization chambers to receive X-rays or visible light converted from X-rays and convert them into electrical signals. The AEC module integrates the electrical signal. As the exposure time increases, the accumulated voltage value increases. When a certain threshold voltage is reached, the AE...

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Problems solved by technology

[0004] There are certain defects in the above two implementation methods: for the ionization chamber dose detection method, firstly, the ionization chamber is complicated to manufacture and the cost is high.

Secondly, the ionization chamber covers the front surface of the detector, which causes X-ray attenuation and affects the capture of X-rays by the detector unit in the area covered by the ionization chamber; for the second exposure method, the disadvantage is that the imaging time is increased, especially when the first exposure adopts extremely Low dosage has higher requirements on the stability of high voltage generator

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