The invention belongs to the technical field of image and video processing, and particularly discloses a high dynamic range image compression method based on a mixed tone mapping algorithm According to the high dynamic range image compression method, the problem about image distorsion when a high dynamic image displays on general display equipment is mainly solved The high dynamic range image compression method comprises the following steps: firstly, using global linear compression based on image types to save the integral effect of the image; secondly, further enhancing the naturalness of the image by using an adaptive avoiding and value burning technology; finally, improving the visibility of image detailed information by using a local tone mapping algorithm based on a dual-side filter According to the high dynamic range image compression method disclosed by the invention, a natural distinct low dynamic image result can be obtained; the high dynamic range image compression method can be widely applied to relevant fields of image and video processing

High dynamic range image compression method based on mixed tone mapping algorithm

An image processing apparatus includes an image information acquisition unit acquiring average brightness of image data and cumulative frequency distribution of pixels related to gradation of the image data; a conversion range determination unit acquiring a conversion threshold value from the average brightness based on a previously set relationship and determining a gradation conversion range where the gradation of the image data is to be converted based on a gradation where a cumulative frequency corresponds to the conversion threshold value in the cumulative frequency distribution; and a gradation conversion unit converting the gradation of the image data in the gradation conversion range.

Image processing apparatus, image processing system, image processing method, and recording medium

The invention discloses an image processing device and method. The image processing method comprises steps of segmenting an image into a plurality of blocks, generating a histogram corresponding to pixel values of each segmented block, calculating a clipping point of each block through the histogram, performing redistribution on the histograms of the blocks, generating mapping functions of the blocks according to the redistributed histograms, recalculating the pixel value of each block and executing double-gamma correction on the image, the pixel value of which is re-calculated.

Image processing device and method

The present invention discloses an image defogging method and device. According to the method, a target gray-scale value is determined by using a summation operation, a gray-scale index of each pixel in an image is subjected to corresponding transformation according to the target gray-scale value, and thus a defogged target image is generated. Compared with the prior art that a defogging function is generated by using complicated mathematical operations such as minimum value solving of a limit function, matrix inversion and the like, and pixels of the image are processed according to the defogging function, the scheme provided by the present invention has the advantages that the number of operations is effectively reduced, and the method and the device can be applied to all kinds of embedded devices and have relatively high applicability.

Image defogging method and device

The invention provides a color reduction method based on histogram shifting. The color reduction method comprises the following steps of: (1) inputting an image, namely, inputting the image, and acquiring gray-scale values of three color channels of the input image; (2) calculating an average gray-scale value, namely, respectively calculating the three color channels so as to obtain an average gray-scale value, and comparing so as to obtain a maximum value, a middle value and a smallest value of the three gray-scale values; (3) calculating shifting amounts, namely, by taking the middle value as basis, calculating two shifting amounts; (4) performing histogram shifting; (5) outputting the image. Due to adoption of the histogram shifting mode, high-quality color reduction can be effectively ensured, the hardware achieving cost can be greatly lowered, and moreover the method is not ineffective for images of single colors or images without white areas, so that the application range of the color reduction method can be greatly expanded, and overall low cost and excellent performance can be achieved.

Color reduction method based on histogram shifting

The invention discloses a method for tone mapping based on histogram equalization. The method comprises the steps of: 1) inputting a high-dynamic range image; 2) acquiring the image brightness and converting the image brightness into a log domain; 3) carrying out histogram statistics; 4) calculating the average brightness of the image, and carrying out segmentation on the histogram by taking the average brightness as a segmentation point; 5) carrying out differentiation setting on mapping parameters of two segments of the histogram; 6) carrying out a histogram equalization algorithm in a segmentation mode; 7) restoring a brightness channel after the tone mapping to an RGB color space; and 8) outputting a displayable low-dynamic range image. According to the invention, the differentiation setting is carried out on the mapping parameters of the two segments after the histogram is segmented, and a bright background is enabled to map linearly as far as possible so as to reduce missing of a highlight part, and a foreground part is still subjected to histogram equalization processing so as to expand the contrast ratio of the image. The method disclosed by the invention can effectively maintain the original brightness of the image while increasing the contrast ration of the image, and effectively improves a phenomenon of brightness saturation in a classical histogram equalization algorithm.

Tan Hongzhou

Papers

Method for tone mapping based on histogram equalization