Real-Time Stripe Noise Removal Method for Endoscope Image

Abstract

Endoscopes use small-size image sensors to achieve imaging, so the image is usually transmitted in high-speed serial signal or analog signal, which are susceptible to interference during transmission, resulting in stripe noise in the image. The endoscope designed in this paper is applied to the urinary system, and the ultra-compact image sensor OV6946 is used to realize in-vivo imaging. In medical endoscope system, stripe noise will seriously affect image quality, which affect the doctor's diagnosis of the disease and even cause misdiagnosis to patients. Therefore, removing the stripe noise in endoscope image has great application value. Most of the stripe phenomenon in image is the introduction of specific frequency noise components. In order to make the stripe noise removal method universal, a real-time method to remove stripe noise is proposed on the basis of analyzing the characteristics of stripe noise. Fourier transform on each line of noise image is implemented in FPGA. The stripe noise spectrum is identified and suppressed in frequency domain to achieve the effect of real-time removal of stripe noise. The experimental results show that the proposed method can effectively suppress the stripe noise of OV6946 output image, preserve the edge and detail information of the image. At the same time, the processing time is only 4.143 μs under the system clock of 300MHz, which can well meet the real-time requirements of endoscopic imaging.