基于Retinex理论的电子内镜图像增强算法

为解决电子内镜图像亮度较暗、光照不均匀和对比度较低的实际问题，提出一种基于Retinex理论的电子内镜血管图像增强算法.算法基于图像差分L₁、L₂范数的特性和对光照进行纹理抑制的实际需求，建立Retinex理论的优化表达式；使用变分法进行求解以获取图像的光照分量与反射分量，分别进行光照矫正和细节拉伸；使用改进的对数直方图均衡调整图像颜色通道比例，提高血管图像的对比度.Matlab测试实验表明，该算法能较好增强电子内镜图像，与同类型算法相比，各评价参数有不同程度提高，具有一定的实际应用价值. 

Endoscopic Image Enhancement Based on Retinex Theory

In order to solve the practical problems of low brightness, nonuniform illumination and low contrast of electronic endoscopy images, an enhanced algorithm based on Retinex theory was proposed. Considering the characteristics of L₁ and L₂ norm of image difference and the actual demand of texture suppression for illumination, the optimization expression of Retinex theory was established. Based on variational method, the illumination component and reflection component of image were obtained and the illumination correction and detail stretching were carried out respectively. To improve the contrast of vascular images, the proportion of image color channels was adjusted with an improved logarithmic histogram. Matlab test results show that the algorithm can enhance the image of electronic endoscopy preferably. Compared with the same type of algorithm, the evaluation parameters can be improved with different degrees, showing a certain practical application value.