Method and device for compressing image within wide dynamic range

Abstract

The invention provides a method and device for compressing an image within a wide dynamic range. The method comprises steps of computing the local mean value of image pixels; computing the transfer function of the image pixels according to the local mean value; increasing or decreasing the original brightness values of the image pixels according to the transfer function to obtain first brightness values; increasing the contrast of the original brightness values according to the local mean value and the transfer function to obtain second brightness values; synthesizing the first brightness values and the second brightness values to obtain third brightness values; and synthesizing the third brightness values and the original brightness values to obtain fourth brightness values. The method and the device compress the image pixels within a wide dynamic range by increasing the brightness values of dark area of the image pixels and decreasing the brightness values of the bright area of the image pixels, achieve a clear and distinct image by increasing the contrast of the image pixels, achieve a natural transition effect for the image pixels by synthesis with the original brightness values, and are simple in computation and easy to be realized by integrated circuits.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to an image wide dynamic range compression method and device. Background technique [0002] The dynamic range of an image refers to the ratio of the brightest brightness value to the darkest brightness value of the image. At present, the original image signal output by general COMS (Complementary Metal Oxide Semiconductor, Complementary Metal Oxide Semiconductor) is 10 bits, 12 bits or 14 bits, while the image is stored as 8 bits, which requires some kind of conversion to compress the dynamic range of the image , converting high dynamic range raw image data into low dynamic range raw image data, this conversion process is called wide dynamic range compression. In actual use, for example, the dynamic range of monitors and printers is narrower, and it is also necessary to compress the dynamic range of the image when displaying and printing the image. [0003] The goal of wi...

AI Technical Summary

Problems solved by technology

[0005] In view of this, it is necessary to address the problems of excessively unnatural output images and large amount of calculation, and provide an image wide dynamic range compression method and system with excessively natural output images, simple calculation, and easy implementation of integrated circuit hardware.

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