LFD Book Forum Intensity and Symmetry
 Register FAQ Calendar Mark Forums Read

#1
09-06-2012, 12:18 AM
 carto Junior Member Join Date: Aug 2012 Posts: 3
Intensity and Symmetry

May I know precisely how to obtain the features intensity and symmetry from a 16 by 16 binary matrix so that I can apply the classifiers in Homework 8?

I thought intensity is the number of 1's divided by 16^2. However, the entries in the intensity column (from the file features.train) multiplied by 16^2 are not integers. Also, why are the symmetry features negative numbers?

I am asking this question because I want to hand write a digit and see if the program can recognize it right.

#2
09-06-2012, 10:16 AM
 rainbow Member Join Date: Jul 2012 Posts: 41
Re: Intensity and Symmetry

There is matlab code http://amlbook.com/support.html. I haven't had a look at it myself.
#3
09-06-2012, 11:05 AM
 magdon RPI Join Date: Aug 2009 Location: Troy, NY, USA. Posts: 597
Re: Intensity and Symmetry

You are correct about the definition of intensity. You can see the support matlab code at

http://www.amlbook.com/support.html

which gives the details of the computation. The images actually contain grayscale values not binary 1,0 which is why the intensity features multiplied by 16^2 are not integers.

Caveat: The images are preprocessed using image processing and normalization algorithms to remove slant and make sure the digits are of comparable size (at least one pixel on the horizontal boundary and one on the vertical boundary are non-white). If you want to apply to your own handwritten digits, you will have to take this into account if you build a classifier from the data on the site.

Quote:
 Originally Posted by carto May I know precisely how to obtain the features intensity and symmetry from a 16 by 16 binary matrix so that I can apply the classifiers in Homework 8? I thought intensity is the number of 1's divided by 16^2. However, the entries in the intensity column (from the file features.train) multiplied by 16^2 are not integers. Also, why are the symmetry features negative numbers? I am asking this question because I want to hand write a digit and see if the program can recognize it right. Thanks in advance!
__________________
Have faith in probability
#4
09-06-2012, 01:52 PM
 carto Junior Member Join Date: Aug 2012 Posts: 3
Re: Intensity and Symmetry

Thank you for the useful responses.

 Tags digit recognization, intensity, symmetry

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home General     General Discussion of Machine Learning     Free Additional Material         Dynamic e-Chapters         Dynamic e-Appendices Course Discussions     Online LFD course         General comments on the course         Homework 1         Homework 2         Homework 3         Homework 4         Homework 5         Homework 6         Homework 7         Homework 8         The Final         Create New Homework Problems Book Feedback - Learning From Data     General comments on the book     Chapter 1 - The Learning Problem     Chapter 2 - Training versus Testing     Chapter 3 - The Linear Model     Chapter 4 - Overfitting     Chapter 5 - Three Learning Principles     e-Chapter 6 - Similarity Based Methods     e-Chapter 7 - Neural Networks     e-Chapter 8 - Support Vector Machines     e-Chapter 9 - Learning Aides     Appendix and Notation     e-Appendices

All times are GMT -7. The time now is 11:05 AM.