Warped document image correction method based on heterogeneous registration strategies

2013 ◽  
Author(s):  
Lijing Tong ◽  
Guoliang Zhan ◽  
Quanyao Peng ◽  
Yang Li ◽  
Yifan Li
2012 ◽  
Vol 182-183 ◽  
pp. 1751-1755
Author(s):  
Xi Feng Zheng ◽  
Feng Chang

For the purposes of correcting the LED display image, a method based on computer simulation is proposed. First, the development of the LED display panel is introduced. Second, analyze the causes of the problem which image in LED display panel has serious high non-uniformity, and introduce the existed correction techniques which are used to reduce the non-uniformity of LED display image. Simultaneously, point out the ground for shortcomings of these techniques. Third, describe the principle of correction method based on computer simulation detail from two steps, which are the luminous collection and luminous copulation. Forth, describe the realization steps of this method in accordance with the third step. Finally, this method is supplied in a LED display panel, whose resolution is 640×480. Experimental results show that this method is able to reduce the non-uniformity of images from 11.06% to 0.98%..


2014 ◽  
Vol 11 (6) ◽  
pp. 602-602 ◽  
Author(s):  
Adam D Coster ◽  
Chonlarat Wichaidit ◽  
Satwik Rajaram ◽  
Steven J Altschuler ◽  
Lani F Wu

2019 ◽  
Vol 16 (5) ◽  
pp. 172988141986446
Author(s):  
Xiaojun Wu ◽  
XingCan Tang

Light changes its direction of propagation before entering a camera enclosed in a waterproof housing owing to refraction, which means that perspective imaging models in the air cannot be directly used underwater. In this article, we propose an accurate binocular stereo measurement system in an underwater environment. First, based on the physical underwater imaging model without approximation and Tsai’s calibration method, the proposed system is calibrated to acquire the extrinsic parameters, as the internal parameters can be pre-calibrated in air. Then, based on the calibrated camera parameters, an image correction method is proposed to convert the underwater images to air images. Thus, the epipolar constraint can be used to search the matching point directly. The experimental results show that the proposed method in this article can effectively eliminate the effect of refraction in the binocular vision and the measurement accuracy can be compared with the measurement result in air.


2014 ◽  
Vol 543-547 ◽  
pp. 2458-2461
Author(s):  
Hong Xia Cui ◽  
Yan Wei Cai

Photogrammetric calibration methods for digital CCD cameras are usually capable of acquiring explicit distortion parameters. However, it would cause the correcting results to be less accurate due to irregular array with explicit image correction method. In order to produce images with less distortion, an implicit model was proposed in this paper. Moreover, the model was applied to correct images from a non-metric camera. The real tests with images indicate the improvement is more obvious in eliminating distortion on images.


Signals ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 540-558
Author(s):  
Keiichiro Shirai ◽  
Tatsuya Baba ◽  
Shunsuke Ono ◽  
Masahiro Okuda ◽  
Yusuke Tatesumi ◽  
...  

This paper proposes an automatic image correction method for portrait photographs, which promotes consistency of facial skin color by suppressing skin color changes due to background colors. In portrait photographs, skin color is often distorted due to the lighting environment (e.g., light reflected from a colored background wall and over-exposure by a camera strobe). This color distortion is emphasized when artificially synthesized with another background color, and the appearance becomes unnatural. In our framework, we, first, roughly extract the face region and rectify the skin color distribution in a color space. Then, we perform color and brightness correction around the face in the original image to achieve a proper color balance of the facial image, which is not affected by luminance and background colors. Our color correction process attains natural results by using a guide image, unlike conventional algorithms. In particular, our guided image filtering for the color correction does not require a perfectly-aligned guide image required in the original guide image filtering method proposed by He et al. Experimental results show that our method generates more natural results than conventional methods on not only headshot photographs but also natural scene photographs. We also show automatic yearbook style photo generation as another application.


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