Bilateral filter

About: Bilateral filter is a research topic. Over the lifetime, 3500 publications have been published within this topic receiving 75582 citations.

The bilateral denoising performance influence of window, spatial and radiometric variance

Abstract: In the research operation of Digital Signal Processing (DSP) and Digital Image Processing (DIP), one of the most essential obstacles is the image denoise algorithm by the reason of a very large demand of high quality noise-free images therefore there are many image denoise algorithms have been invented in the time of two decades. Bilateral filter is one of the most impressive and feasible algorithms, which is usually applied for denoise propose, but the performance of the Bilateral filter is substantially bank on three parameters: spatial variance, radiometric variance and window size. Consequently, this paper investigates the performance influence impact of spatial variance, radiometric variance, window size for the Bilateral Filter in the denoise propose. In the denoise experiment, Bilateral filter (BF) is applied on three noisy standard images under five Gaussian noise power levels and the best results in the PSNR prospective point of view from deniose algorithm is picked. Moreover, an optimal value of three parameters: spatial variance, radiometric variance, window size, which make the performance of Bilateral filter the highest PSNR, are extensively investigated for each types of tested images and each noise powers.

Non-uniform clocking system for area imaging device

Abstract: An area imaging device comprises an area image sensor and means to adjust the vertical and horizontal clocking rate used to transfer pixels from an array of photo-sensors to a serial output of the area image sensor. The non-uniform clocking rates of the present invention reduce the amount of memory necessary to implement pan and zoom features by effectively separating image and non-image pixels during scanning. This also allows images collected in one format to be displayed on a display device designed for a second format. For each image scan, the area image sensor is divided into active, recovery, and inactive regions according to whether the pixels within the region are displayed, adjacent to displayed pixels, or neither adjacent to image pixels nor displayed, respectively. Rows of pixels are transferred to a horizontal shift register at a vertical scanning rate which is increased for rows that include no image pixels. The pixels of each row are then clocked out of the horizontal shift register at a rate that is adjusted according to the region of the area image sensor in which the pixels originated. Non-image pixels are shifted out at a high rate, while image pixels are shifted out at a rate that minimizes distortion of the image. Recovery pixels which segregate image and non-image pixels, are shifted out of the horizontal shift register at a slow rate to flush charge transfer cells of any accumulated excess charges.

Automatic correction of exposure problems in photo printer

Abstract: In this paper we consider a problem of automatic enhancement of amateur photos in photo printer. The purpose of correction consists of making photos more pleasant for an observer. The photos with various exposure problems and with poorly distinguishable details in shadow areas are analyzed. Our approach is based on contrast stretching and alpha-blending of both brightness of the initial image and estimations of reflectance. For obtaining reflectance estimation a simplified illumination model is used. The luminance is estimated using bilateral filter. Reflectance is estimated using heuristic functions of ratio between brightness of the initial image and estimation of luminance. The correction parameters are chosen adaptively based on histogram analysis. Noise suppression and some sharpening occur during correction. The time and memory optimization issues are considered. Look-up tables and recursive separable bilateral filter are applied to speed up the algorithm. The quality of the algorithm is evaluated by surveying of observer's opinions and by comparisons with already existing software and hardware solutions for local shadow correction. The proposed algorithm was implemented into firmware of Samsung dye-sublimation compact photo printer.

A bilateral filter in gradient domain

Abstract: In this paper, a bilateral filter in gradient domain is first proposed. It is then applied to study detail enhancement via multi-light images and noise reduction of differently exposed low dynamic range images. These two applications show that the proposed filter can be applied to extract fine details from a set of images simultaneously and to provide flexibility for noise reduction from selected areas of an image.