A fast iso denoising method and system based on lifting wavelet transform

Abstract

The invention discloses a fast ISO denoising method and system based on lifting wavelet transform, relates to image processing technology, and aims to propose a fast ISO denoising algorithm capable of simultaneously retaining low-contrast information and high-contrast edge information of an image. Technical points of the present invention: decompose the image into a single channel to obtain the Y channel image, U channel image and V channel image; carry out n-layer linear lifting wavelet transform on the Y channel image; pair the results of the wavelet transform of the 3rd to n layers one by one Denoise the wavelet detail image in the image; wavelet inverse transform obtains the denoised approximate image in the first layer wavelet transform result; denoise the approximate image in the first layer wavelet transform result again; wavelet inverse transform obtains the original space Denoising the Y-channel image in the original space; performing wavelet transformation and denoising on the U-channel image and V-channel image respectively; and obtaining the denoising result of the three-channel image.

Description

technical field [0001] The invention relates to image processing technology, in particular to a fast ISO denoising method. Background technique [0002] In recent years, with the digitization of cameras and the use of mobile phones, an era of photography for all has come. People can take pictures at any time, in any scene, and with any focus. [0003] In low-brightness or fast-changing scenes, the ISO speed of the image sensor is usually increased to increase the photosensitive speed, so that the camera can obtain more light in a short time. Increasing the speed of ISO is usually achieved by increasing the gain of the electrical signal and lowering the photosensitive threshold. When the speed of the sensor is increased, more random noise is often introduced. If the ISO speed is increased above 400, the random noise will gradually become more obvious. [0004] The noise brought by high ISO greatly reduces the quality of the image, and because of the increase of useless noi...

AI Technical Summary

Problems solved by technology

[0006] The advantage of wavelet domain denoising is that it is fast and can well preserve the low-contrast information of the image, but its disadvantage is that it is prone to artifacts and the edge information of the image is blurred

[0007] The most representative denoising algorithm based on spatial domain is non-local mean denoising. Its advantage is that the high-contrast information such as the edge of the image can be well protected, and the denoising effect is more obvious, but its disadvantage is that it is slow and easy. The low-contrast information of the image is lost, and the phenomenon of over-smoothing occurs

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