Efficient light balancing techniques for text images in video presentation systems

This paper presents a novel light balancing technique to compensate uneven illumination based on adaptive gain control, which is specially designed for text images. A segmentation technique is used to remove contents from a sampling image with block-based processing. To achieve high performance, the block size is adaptively selected for different character size according to image features. Then the linear interpolation is employed to generate new values instead of text pixels to obtain a background image. Referring to this image, an adaptive technique is presented to process the sampling image to achieve light balancing. Simulations demonstrate that our light balance processing can achieve better quality than the conventional methods for camera systems.