Rank: 298 based on 384 downloads (last 30 days) and 4 files submitted
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Guanglei Xiong

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Tsinghua University, Beijing, China

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Files Posted by Guanglei View all
  • 1 - 4 of
  • 4
Updated   File Tags Downloads
(last 30 days) 		Comments Rating
13 Jun 2006 Screenshot Local Adaptive Thresholding Threshold with local statistics, such as mean or median. Author: Guanglei Xiong threshold adaptive lo..., filtering 156 15
  • 4.46154
4.5 | 13 ratings
09 Sep 2005 Screenshot Gradient using first order derivative of Gaussian Output the gradient image of a grayscale image Author: Guanglei Xiong filtering, gradient gaussian, fod, image proc, first order derivativ... 133 8
  • 4.375
4.4 | 8 ratings
07 Sep 2005 Screenshot Local Normalization Reduce the difference of the illumination. Author: Guanglei Xiong image processing, uniformi, local normalization g..., enhancement 44 2
  • 4.75
4.8 | 4 ratings
25 Aug 2005 Screenshot Fuzzy c-means thresholding Thresholding by 3-class fuzzy c-means clustering. Author: Guanglei Xiong filtering, threshold fuzzy cmean... 51 2
  • 4.0
4.0 | 2 ratings
Comments and Ratings on Guanglei's Files View all
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  • 34
Updated File Comment by Comments Rating
05 Sep 2009 Local Adaptive Thresholding Threshold with local statistics, such as mean or median. Author: Guanglei Xiong bhattacharya, sanjay

it can detect the letters even where its very dark (see the lines in the end) line 8 etc
05 Sep 2009 Local Adaptive Thresholding Threshold with local statistics, such as mean or median. Author: Guanglei Xiong bhattacharya, sanjay

I have written a code without using any std functions like imfilter etc, its purely based on fundamentals.

CHECK OUT THE OUTPUT IMAGES
http://sites.google.com/site/adapthresh/
05 Sep 2009 Local Adaptive Thresholding Threshold with local statistics, such as mean or median. Author: Guanglei Xiong bhattacharya, sanjay

Nice code, but not applicable in extreme situations.

13 Aug 2009 Gradient using first order derivative of Gaussian Output the gradient image of a grayscale image Author: Guanglei Xiong Kylberg, Gustaf

Seems like you are calculating too small kernel sizes when higher values of sigma are used, e.g., when sigma>10 the kernels are clearly truncated. With sigma>40 your kernel size becomes imaginary.
10 Aug 2009 Gradient using first order derivative of Gaussian Output the gradient image of a grayscale image Author: Guanglei Xiong piere, samur

can you mention the mathematical basis for kernel size and normalization steps. thx.

epsilon = 1e-2;
halfsize = ceil( sigma * sqrt(-2*log(sqrt(2*pi)*sigma*epsilon)) );

hx = hx/sqrt(sum(sum( abs(hx).*abs(hx) )));
Top Tags Applied by Guanglei
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filtering, enhancement, first order derivative, fod, gradient gaussian
Files Tagged by Guanglei View all
  • 1 - 4 of
  • 4
Updated   File Tags Downloads
(last 30 days) 		Comments Rating
13 Jun 2006 Screenshot Local Adaptive Thresholding Threshold with local statistics, such as mean or median. Author: Guanglei Xiong threshold adaptive lo..., filtering 156 15
  • 4.46154
4.5 | 13 ratings
09 Sep 2005 Screenshot Gradient using first order derivative of Gaussian Output the gradient image of a grayscale image Author: Guanglei Xiong filtering, gradient gaussian, fod, image proc, first order derivativ... 133 8
  • 4.375
4.4 | 8 ratings
07 Sep 2005 Screenshot Local Normalization Reduce the difference of the illumination. Author: Guanglei Xiong image processing, uniformi, local normalization g..., enhancement 44 2
  • 4.75
4.8 | 4 ratings
25 Aug 2005 Screenshot Fuzzy c-means thresholding Thresholding by 3-class fuzzy c-means clustering. Author: Guanglei Xiong filtering, threshold fuzzy cmean... 51 2
  • 4.0
4.0 | 2 ratings
 

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