The invention provides an image self-adaptive digital quantification structure which comprises a two-value capacity discharge digital quantification curve generating module, a histogram statistic module, a histogram threshold value parameter acquiring module, a histogram threshold value parameter correcting module and a gray value calculating module. The image contrasts continuously acquired in real time are self-adaptively regulated on the basis of an ASIC (application specific integrated circuit) streamline structure, then images acquired through different dry, wet and shallow medium contact surfaces are excellent in contract uniformity, the processing speed is optimized, and the digital image which is regulated through same frame contrast is output while a frame image analog signal is acquired. According to the invention, full custom ASIC achieves image self-adaptive digital quantification, a streamline structure of processing the image while acquiring the image is conducted, the processing speed is high, the cost is low, and the power consumption is low.