Joint Up-sampling High Dynamic Range Images with a Guidance Image
Si-qi Han · Journal of Mathematics and Informatics · 2019
In this paper, we address the problem of acquiring guidance images for use in joint up-sampling of high dynamic range (HDR) images.A guidance image is usually an unprocessed high-resolution image that is indispensable to joint up-sampling, which is aimed at accelerating a large class of image processing operators.However, the guidance image is blank-posed in joint up-sampling of the HDR image, which involves the process where multiple low dynamic range (LDR) images with various exposure times in the same scene are synthesized into one image with a greater dynamic range; Such many-toone operations limit joint up-sampling in being applied to this field.To this end, we propose an HDR guidance image (HGI), which is an image type generated by weighted averaging LDR images into a single with rich contour information.The huge advantage of joint up-sampling is that the cost of running the original algorithm is at a greatly reduced resolution.Since HGI synthesis takes about 3-70ms, and joint up-sampling of an HDR image takes about 20-300ms, most operations can be done with GPU shaders.Compared with the conventional methods of HDR image reconstruction, using joint upsampling can achieve 3-10 times the performance acceleration.We demonstrate that joint up-sampling using our guidance images can produce high-resolution HDR images with no visible degradation compared to the image produced by the conventional method.