Image Gamma correction method for creating lookup table based on Taylor series fitting

Abstract

The invention discloses an image Gamma correction method for creating a lookup table based on the Taylor series fitting. The method comprises the following sequential steps: determining a pre-compensation characteristic function according to a given Gamma value and the maximum input image depth value, determining leading discrete sampling points according to the preset accuracy requirement, conducting Taylor series expansion on the leading discrete sampling points, calculating and storing Taylor series fitting multinomial coefficients at the positions of the leading discrete sampling points to obtain a discrete lookup table, utilizing the multinomial interpolation method for determining color lookup values at the positions of sequence points between all the adjacent leading sampling points to obtain a complete lookup table, inputting the depth of an image, and conducting Gamma correction on the image according to the complete lookup table. The image Gamma correction method for creating the lookup table based on the Taylor series fitting is strong in compatibility, small in pre-storage table, low in storage requirement and high in precision.

Description

technical field [0001] The invention relates to the field of visual image processing, in particular to an image gamma correction method for establishing a lookup table based on Taylor series fitting. Background technique [0002] Gamma correction originally originated from the nonlinear characteristics of a cathode ray tube (CRT, Cathode Ray Tube). The relationship between the input voltage of the CRT electron gun and the output light satisfies the 5-2 power function, that is, the brightness displayed on the fluorescent screen is proportional to the 5 / 2 power of the input voltage, and this index is called Gamma (γ). When the value used for Gamma correction is greater than 1, the highlights of the image are compressed and the dark parts are expanded; when the value used for Gamma correction is less than 1, the highlights of the image are expanded and the dark parts are compressed. [0003] Gamma correction is generally used to smoothly expand shadow details. If the output i...

AI Technical Summary

Problems solved by technology

However, the number of sub-sampling points is determined by the maximum difference between the straight line segment and the Gamma curve segment between its dominant sampling points. Compared with the traditional complete look-up table, the stored Gamma look-up table can be reduced, but it must be guaranteed There is still the problem of occupying a large amount of memory capacity

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