Real Time Image Processing System For Electronic Fluorescence Endoscope

At present,surgical resection,as one of the main means of cancer treatment,is developing in the direction of minimally invasive and accurate.endoscopy is one of the most important means of observation in minimally invasive surgery.Compared with traditional fiberoptic endoscopy,electronic endoscopy can help doctors more easily observe deep lesions.However,in minimally invasive tumor resection,doctors only rely on visual information provided by endoscopy to identify tumors,which leads to the omission of small tumors with similar color and shape to normal tissues.Fluorescence molecular imaging is a new imaging method.The principle is to increase the contrast between pathological and normal tissues by labeling tumor cells with fluorescent agents.Due to the imaging system is too large or inconvenient to operate,it is mostly used in open surgery or medical research.Therefore,this paper designs a single sensor timesharing acquisition system with real-time image fusion function for color background image and fluorescent image,which provides a realization scheme for the combination of fluorescent molecular materials and electronic endoscope imaging system.The system uses the LED with optical fiber as the white light source.Distinguish dark field from light field according to the switch state of light source,and the switch frequency is consistent with the frame rate of the camera.By changing the exposure and gain of the camera through the frame gap,the photograph can have the appropriate brightness and clarity in the light and dark field.After receiving images,FPGA stores them in the DDR2 separately.The fusion image with high difference between label and normal tissue is obtained by buffer control and synthesis algorithm,which is written to No.3 storage space,and the image data is output to the display with standard VGA timing.The threshold setting of image fusion is a semi-automatic mode which combines OTSU algorithm with manual adjustment.It can not only change the threshold with the decrease of luminance of fluorescent agent,but also offset the error of threshold calculation flexibly.Compared with the traditional multi-sensor mode,it reduces the size of image acquisition structure and eliminates the matching error.Compared with the traditional single-sensor mode,the method of automatic switching of light source and real-time fusion function enables doctors to observe the details of normal tissue while locating the marker tissue.Finally,we test the fluorescent labeling function and real-time performance of the system.The results show that by adjusting the threshold and gain parameters,the system can effectively display the texture of the labeled area,highlight the outline of the labeled area,realize the labeling function of the fluorescent area,and the fused image can output smoothly.