Pre-Processing of X-Ray Medical Image Based on Improved Temporal Recursive Self-Adaptive Filter

The random noises caused by different devices in the process of X-ray imaging make images degraded, which results in incomplete or even incorrect medical diagnoses. The image pre-processing is the primary procedure of digital X-ray imaging device. Due to the features of X-ray medical image, the temporal recursive filter can be used, whose filtering coefficient decreases exponentially with the difference of two adjacent frames. However, considering the hardware implementation complexity in real-time dynamic processing, an improved self-adaptive filtering algorithm is proposed, of which the filtering coefficient is generated by a linear decay function. We use a field programmable gate array (FPGA) and other peripherals to design and implement the X-ray medical image pre-processing system based on the improved self-adaptive filter. The design fundamentals and methods are discussed in details, including video decoder, encoder, processing, and display. The experiment results show that the proposed algorithm and system improve the imagepsilas signal-noise-ratio effectively, after 4 to 8 frame recursions. The pre-processing system can be practically used in digital X-ray imaging device.