Illumination compensation for microscope images based on illumination difference estimation

The DNA ploidy analysis which measures the relative content of DNA in cells by image processing has a wide range of applications in cancer diagnosis. However, the measured results of the same cell in different positions are different because of uneven illumination, which may reduce the measurement accuracy and the diagnosis performance. Many methods are proposed to compensate for uneven illumination, but they are generally aimed at image enhancement, segmentation, or recognition and therefore not suitable for cell measurement. To solve this problem, a compensation method without using white-referencing images is proposed in this paper. This method first grabs images with cells and then removes the cells after locating them on the slide by image segmentation. Next, the regions of removed cells are filled by the thin-plate spline interpolation to obtain background images. Then, two methods used for estimating illumination difference from the background images are provided. Finally, the illumination compensation is made by adding the input image and the illumination difference image. Experiments show that the methods proposed can remove uneven illumination without using white-referencing images.