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Light-source color estimation method of color images on basis of sorting correction

A color image and light source technology, applied in the field of computer vision and image processing, to achieve the effect of small quantity, high precision and fast speed

Active Publication Date: 2017-01-04
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the problem that the estimation method of the light source color of the image scene in the prior art cannot satisfy the occasions where the accuracy of the estimated light source color is very high, and proposes a color image light source color estimation method based on classification correction

Method used

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  • Light-source color estimation method of color images on basis of sorting correction
  • Light-source color estimation method of color images on basis of sorting correction
  • Light-source color estimation method of color images on basis of sorting correction

Examples

Experimental program
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Embodiment 1

[0047] Download all the images (321 in total) of the currently internationally recognized image library SFU object for estimating scene light source colors and their corresponding real light source colors (standard light source) L. The image size is 468×637, and the first 214 images in the image library image as the training set image, select one of the remaining images tools_ph-ulm.tif (such as figure 2 Shown) is tested as the test image to be processed, and all images have not undergone any preprocessing of the camera itself (such as tone correction, gamma value correction). Then the detailed steps of the present invention are as follows:

[0048] S1. Extract the edge features of the training image: use 214 color images of known light sources as the original training set T, and perform convolution operations with the template G (Gaussian gradient operator) after derivation of the Gaussian distribution to obtain each pixel of the image The edge value corresponding to the po...

Embodiment 2

[0067] The pixel values ​​of each color component of the original input image are respectively corrected by using the light source color values ​​under each color component calculated in step S5. Taking a pixel point (0.335,0.538,0.601) of the test image input in step S3 as an example, the corrected result is (0.335 / 0.3312,0.538 / 0.3365,0.601 / 0.3430)=(1.0115,1.5988,1.7522), After normalization, it becomes (0.2319, 0.3665, 0.4016), and then multiply the corrected value by the standard white light coefficient Get (0.1339, 0.2116, 0.2319) as the pixel value of the final output corrected image, do similar calculations for other pixels of the original input image, and finally get the corrected color image, such as Figure 5 shown.

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Abstract

The invention discloses a light-source color estimation method of color images on the basis of sorting correction. The light-source color estimation method comprises the following steps of: extracting edge features of images on a group of images with known light-source colors, then learning by a least square method and obtaining a correction matrix between the edge features and light sources; then extracting the edge features of testing images to be processed, multiplying the edge features and the correction matrix, and obtaining a rough light-source estimation; then finding a kind of training images with the features similar to those of the testing images to be processed in a manner of searching for K adjacent images in a feature space so as to relearn and obtain accurate light-source estimation. The light-source color estimation method disclosed by the invention involves fewer parameters and also has the characteristics of simple calculation and fast speed and the like due to simple and fewer extracted features; in addition, the light-source color estimation method is based on learning, so that the processing effect is good and the accuracy is high. Therefore, the light-source color estimation method is very suitable for occasions with higher requirements for estimation of the light-source color.

Description

technical field [0001] The invention belongs to the technical field of computer vision and image processing, and in particular relates to the design of a method for estimating the color of a color image light source based on classification correction. Background technique [0002] In a natural environment, the same object will appear in different colors under the illumination of different colors of light. For example, green leaves are yellowish in the morning light, but blue in the evening. The human visual system can resist the color change of the light source, so as to constantly perceive the color of the object, that is, the visual system has color constancy. However, limited by technical conditions, the machine does not have this ability, and the pictures taken by physical equipment, such as cameras, will have serious color cast due to the change of the color of the light source. Therefore, how to accurately estimate and remove the color of the light source in the scene...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/62G06K9/46
CPCG06V10/462G06F18/214
Inventor 李永杰张明高绍兵任燕泽
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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