Rank: 49 based on 874 downloads (last 30 days) and 51 files submitted
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Michael Chan

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Personal Profile:

I was a Security Specialist for software security and cryptology [2006 to 2008]. Following, I joined a firm under a statutory board involving in National Security Frameworks as a Senior Consultant [2009].

I would like very much to meet altrulistic, courageous, purposive, perspicacious people who are seeking to work on a noble cause. It is a very nourishing experience to share life lessons with compassionate, passionate people who are relentlessly seeking discoveries and growth.

Professional profile:
http://linkd.in/MichaelElijah

My Teachers:
[1] http://bit.ly/ProfessorDavidAkopian
[2] http://bit.ly/ProfessorSosAgaian
[3] http://bit.ly/ProfessorArtyomGrigoryan
[4] http://bit.ly/ProfessorErMengHwa
[5] http://nanyang.academia.edu/DanielTan

[6] http://bit.ly/ProfessorRuanJianhua
[7] http://bit.ly/ProfessorFredHudson
[8] http://bit.ly/ProfessorByeongKilLee
[9] http://bit.ly/ProfessorJinYufang
[10] http://bit.ly/ProfessorFengYusheng

Professional Interests:

 

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Files Posted by Michael View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
20 Aug 2014 Screenshot Figlet Statement Generator Demonstrate how to create figlet statements from font templates. Author: Michael Chan utility 33 0
11 Aug 2014 Screenshot Big Integer Arithmetic Demonstrate big integer arithmetic, such as multiplication, addition, subtraction, etc. Author: Michael Chan big integer 29 1
  • 5.0
5.0 | 1 rating
08 Aug 2014 Screenshot Serial Downloader To demonstrate how to create sniffer to scan for (published or hidden) files on a server. Author: Michael Chan files, search 30 0
05 Aug 2014 Screenshot Linear congruential random number generator Demonstrate the principal idea of getting random bits Author: Michael Chan random, statistics 29 0
23 Jul 2014 Screenshot Modular Exponentiation y = x^e mod n Author: Michael Chan arithmetic, modular exponentiatio... 12 0
Comments and Ratings by Michael View all
Updated File Comments Rating
14 Aug 2014 ColorBrewer: Attractive and Distinctive Colormaps The complete palette of ColorBrewer colormaps. Simple selection by scheme name and map length. Author: Stephen Cobeldick

Beautiful work, Stephen.

26 Jun 2014 Wavelet Decomposition For Images The demo decouples the wavelet operations from the plotting. Author: Michael Chan

Hi Mehdi,
You can extract the coefficients at different levels as an obversation with any existing image(s). Would you have a wavelet feature extraction algorithm in mind or a paper you have referred to?

22 Jun 2014 Using Gauss' Algorithm to solve simultaneous linear congruences for Chinese Remainder Theorem Gauss' Algorithm to solve for Chinese Remainder Theorem (CRT) Author: Michael Chan

Number of linear congruences to be extended in the next update.

20 Jan 2013 arrow.m Draw a line with an arrowhead. Author: Erik Johnson

How do you turn off the arrow heads at either ends of the start and stop points?

16 Jan 2013 Wavelet Decomposition For Images The demo decouples the wavelet operations from the plotting. Author: Michael Chan

Hi Rewati, it is. It's a form of lossy compression where you keep only the coefficients of the Approximate region(s).

Comments and Ratings on Michael's Files View all
Updated File Comment by Comments Rating
15 Aug 2014 Convert Image To And From Graph Coordinates Illustrates mapping of binary image to graph coordinates and vice-versa. Author: Michael Chan Joan

Could you make one version that map fingerprint images to X-Y coordinates? I have sent some programs to your email. Please help me for the project.

14 Aug 2014 Convert Image To And From Graph Coordinates Illustrates mapping of binary image to graph coordinates and vice-versa. Author: Michael Chan Cobeldick, Stephen

Poorly written, and with no clear purpose.

Although the example illustration shows black/dark pixel detection using this function with a neat plot of the detected pixel locations, the non-existent documentation conveniently does not mention that this only works for indexed image data, and only then if the second color index (1) happens to correlate to the pixel color of interest. Users who try to use this function with their existing image data, or import images as RGB or grayscale, will be sorely disappointed by the two empty vectors that this function will return. Or might find that the function detects all white pixels instead. The non-existent documentation sadly does not mention minor details like this.

The absent help also does not explain the purpose of the four arguments <upperRangeX>, <lowerRangeX>, <lowerRangeY>, <upperRangeY>: are these to select a part of my input image, or to scale the output data, or, just like the internal variables <x_plot_min>, <x_plot_max>, <y_plot_min> and <y_plot_max>, simply remain completely unused? Luckily MATLAB includes the "mlint" function, which easily and quickly allows checking for basic coding mistakes like this: use of "mlint" is recommended before uploading onto FEX.

The author does make the comment "Caveat: For demo reference only". This is certainly true, as without any documentation, input checking or error messages the user is forced to waste considerable time trying to figure out what this submission does. The lack of constructive comments makes the purpose of interestingly named variables, such as <pixeliZedScratchPad>, somewhat opaque (answer: this is the image data). If it is intended as a reference, then the lack of any helpful explanations, reasoning or justifications leaves the user to make up their own mind about the code.

The file "usage_ImageToAndFromGraphCooridinates.m" calls <close all; clear all; clc;> at the top of the script which removes all variables in the workspace: some might consider this to be a bit impolite. It is certainly bad practice for a FEX submission, as has been explained and discussed many times before on FEX.

The overall impression is that this is someone's homework attempt, but hardly something that is suitable for submission on FEX. For those who require this functionality, the submission essentially does this:

% Read data from a B&W, RGB or indexed image file:
[A,map] = imread(imagefile);
% Convert indexed to RGB:
if ~isempty(map)
A = ind2rgb(A,map);
end
% Find the black pixels:
[Y,X] = find(0==mean(A,3));
% Plot (inverting Y-axis):
plot(X,1+max(Y(:))-Y,'*')

10 Aug 2014 Big Integer Arithmetic Demonstrate big integer arithmetic, such as multiplication, addition, subtraction, etc. Author: Michael Chan Joan

09 Aug 2014 Big Integer Arithmetic Demonstrate big integer arithmetic, such as multiplication, addition, subtraction, etc. Author: Michael Chan Cobeldick, Stephen

This submission might be interesting for those who want to see how "for" loops can be used to perform basic arithmetic.

For those who need to use high precision numbers for calculations, consider John D'Errico's excellent Variable Precision Integer Arithmetic:
http://www.mathworks.com/matlabcentral/fileexchange/22725
or his HPF - a big decimal class:
http://www.mathworks.com/matlabcentral/fileexchange/36534

26 Jun 2014 Wavelet Decomposition For Images The demo decouples the wavelet operations from the plotting. Author: Michael Chan Chan, Michael

Hi Mehdi,
You can extract the coefficients at different levels as an obversation with any existing image(s). Would you have a wavelet feature extraction algorithm in mind or a paper you have referred to?

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