Method and device for grayscale compensation and noise suppression on images

A noise and image technology, applied in the field of grayscale compensation for non-periodic noise in images, can solve the problems of destroying the periodicity of grating shadows, reducing ringing, and failing to filter out grating shadows to produce ringing effects, etc. The effect of improving image quality

Active Publication Date: 2019-05-28
深圳迈瑞软件技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the commonly used interpolation methods such as linear interpolation and cubic interpolation are used to interpolate the bad lines, only a smooth transition can be obtained, which destroys the periodicity of the grating shadow, resulting in ringing effects caused by frequency domain filtering and cannot effectively reduce ringing Effect
For DR images with grid shadows, the first method usually cannot completely filter the grid shadows without producing ringing effects at bad lines, while the second method needs to consider the grid shadows while grayscale compensation influence, that is, we should not only consider simple neighborhood interpolation, but also take into account the periodicity of grating shadows
However, no research has given an algorithm that can effectively remove grid shadows and minimize ringing at the same time.

Method used

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  • Method and device for grayscale compensation and noise suppression on images

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Embodiment 1

[0074] This embodiment provides a method for performing grayscale compensation on aperiodic noise in an image, including the following steps:

[0075] Image acquisition step: acquiring an image to be processed, which is an image disturbed by periodic noise;

[0076] Period determination step: determine the period of the periodic noise;

[0077] Data acquisition step: detecting non-periodic noise in the image to be processed, and obtaining data near the non-periodic noise as input data;

[0078] Value recovery step: Substituting the period and input data of periodic noise points into the signal separation model, optimizing the signal separation model, and obtaining the clean image signal, periodic noise and non-periodic noise corresponding to the input data, and recovering according to the obtained results The pixel value where there is aperiodic noise in the input data. The signal separation model here can be obtained by constructing the aforementioned method; or directly ca...

Embodiment 2

[0096] Such as Figure 6 In the part shown by the solid line, in this embodiment, the method for recovering the pixel value of the non-periodic noise in the image disturbed by the periodic noise (that is, for the bad line or bad line in the DR image with grid The general process of pixel value recovery method for point and other sparse noise) is: first obtain the grating shadow direction (that is, the direction of periodic noise, which can be understood as the visual distribution direction of periodic noise in the image), according to the grating Determine whether interpolation is needed according to the shadow direction, and then estimate the period of the grating shadow, so that the influence of this periodic component can be considered when estimating the pixel value at the non-periodic noise, so that the pixel value at the non-periodic noise can be restored.

[0097] The acquisition of the grid shadow direction can be automatically detected by means of image processing; of...

Embodiment 3

[0127] In this embodiment, the gray level compensation of the DR image with a grid is still taken as an example for illustration. This embodiment is implemented based on the above-mentioned embodiment 1 or 2, but the determination of the grating shadow period involved in it is based on the SPX model Implemented algorithm.

[0128] The size of the grid shadow period in the embodiment is realized based on the aforementioned SPX model and its mathematical optimization problem, and can be obtained by the following algorithm:

[0129] For the input image to be processed, one of the regions of interest is selected for periodic scanning to find the best period. The candidate period is an empirical value, for example, it can be set to a range of 5-10, or adjusted according to the actual situation. The region of interest should preferably choose an area with a relatively obvious cycle, avoid the area where the cycle signal is too weak due to insufficient or excessive dose, or use a ran...

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Abstract

This application relates to a method and device for performing grayscale compensation and noise suppression on an image, including: obtaining an image to be processed interfered by periodic noise; determining the period of the periodic noise; detecting non-periodic noise in the image to be processed, and obtaining The data near the periodic noise is used as the input data; the period and input data of the periodic noise are substituted into the signal separation model, and the signal separation model is optimized to obtain a clean image signal, periodic noise and non-periodic noise corresponding to the input data, Restoring the pixel value at the non-periodic noise in the input data according to the obtained result. The present invention is realized based on the SPX model, through which the periodic noise signal, the non-periodic noise signal and the clean image signal can be separated, and the influence of the periodic noise can be considered when performing grayscale compensation, so that after grayscale compensation due to the continuation The periodicity is eliminated, and there is no ringing effect in the subsequent noise suppression, thereby improving the image quality.

Description

technical field [0001] This application relates to image processing technology, in particular to a method and device for grayscale compensation of non-periodic noise in an image, and a method and device for noise suppression using this method or device, in particular, the image is an image disturbed by periodic noise. Background technique [0002] Digital Radiography (Digital Radiography, DR) is a technology that uses digital sensors to detect X-rays to take medical photos. It stores and processes medical images digitally, and has the advantages of fast acquisition and transmission, easier image enhancement and Display and other advantages, has been widely used in various medical examination and diagnosis. [0003] In order to improve the resolution of DR images, most DR products will add an anti-scatter grid between the X-ray receiving panel and the human body. The function of the grid is to let the X-rays from the front through the human body pass through while filtering...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06T5/00
Inventor 赖勇铨邹耀贤林穆清许鹏
Owner 深圳迈瑞软件技术有限公司
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