LFD Book Forum Questions about Symmetry and Average Intensity of Zip Code digit
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#1
10-04-2012, 01:42 PM
 mileschen Member Join Date: Sep 2012 Posts: 11
Questions about Symmetry and Average Intensity of Zip Code digit

I have some questions about the Symmetry and Average Intensity of the image of Zip Code digit. That is, what the definition of them?

For a digit in the data, there are 256 grayscale values ranging from -1 to 1, -1 here denotes white, 1 is black. But when plotting in Matlab, the image should be 16 x 16 matrix, and with 1 means white, 0 means black.

Then, does Symmetry should be calculated based the on the 16 x 16 matrix of the grayscale values? Also, does the average intensity means that it is the mean value of the 256 grayscale values (between -1 and 1)?
#2
10-04-2012, 08:57 PM
 magdon RPI Join Date: Aug 2009 Location: Troy, NY, USA. Posts: 595
Re: Questions about Symmetry and Average Intensity of Zip Code digit

The average intensity is a measure of the size of the digit. One choice for this could be the mean value of the 256 grayscale values.

Yes, symmetry is defined on the 16x16 image. By symmetry, we mean visual measure of symmetry in this 16x16 image. Some such symmetries could be reflection, rotation, etc.

Quote:
 Originally Posted by mileschen I have some questions about the Symmetry and Average Intensity of the image of Zip Code digit. That is, what the definition of them? For a digit in the data, there are 256 grayscale values ranging from -1 to 1, -1 here denotes white, 1 is black. But when plotting in Matlab, the image should be 16 x 16 matrix, and with 1 means white, 0 means black. Then, does Symmetry should be calculated based the on the 16 x 16 matrix of the grayscale values? Also, does the average intensity means that it is the mean value of the 256 grayscale values (between -1 and 1)?
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#3
10-23-2012, 09:08 PM
 tusar Junior Member Join Date: Oct 2012 Posts: 1
Re: Questions about Symmetry and Average Intensity of Zip Code digit

Then, does Symmetry should be calculated based the on the 16 x 16 matrix of the grayscale values? Also, does the average intensity means that it is the mean value of the 256 grayscale values (between -1 and 1)?
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#4
01-17-2013, 10:53 AM
 magdon RPI Join Date: Aug 2009 Location: Troy, NY, USA. Posts: 595
Re: Questions about Symmetry and Average Intensity of Zip Code digit

Yes to both questions.

Quote:
 Originally Posted by tusar Then, does Symmetry should be calculated based the on the 16 x 16 matrix of the grayscale values? Also, does the average intensity means that it is the mean value of the 256 grayscale values (between -1 and 1)?
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