Quick ISO (international standardization organization) denoising method and system based on lifting wavelet transform

Abstract

The invention discloses a quick ISO (international standardization organization) denoising method and a quick ISO denoising system based on lifting wavelet transform, relates to the image processing technology, and aims to disclose a quick ISO denoising algorithm which can be used for simultaneously retaining low-contrast information and high-contrast edge information of images. The technical key point is that the quick ISO denoising method comprises the following steps: performing single-channel decomposition on images, thereby obtaining a Y-channel image, a U-channel image and a V-channel image; performing n-layer linear lifting wavelet transform on the Y-channel image; one by one denoising wavelet detail images in results obtained by transforming wavelets of the third layer to n-th layer; performing inverse wavelet transform to obtain denoised similar images in first-layer wavelet transform results; denoising the similar images in the first-layer wavelet transform results again; performing inverse wavelet transform to obtain the Y-channel image of original space; denoising the Y-channel image of the original space; respectively performing wavelet transform on the U-channel image and the V-channel image and denoising the U-channel image and the V-channel image; and obtaining denoised results of the Y-channel image, the U-channel image and the V-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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