How to calculate enrgy of a matrix
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I am having a 2*2 matrix. say it is A=[1 2; 3 4]; how to calculate energy with this.
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Image Analyst
2016-3-29
What is your definition of energy? You could say that if the array is an image, the pixel values are energy already so you can just sum the array
energy = sum(A(:));
Or you can use the energy as defined from the gray level co-occurrence matrix of the array. From the help for graycoprops():
Calculate statistical properties of the GLCM.
stats = graycoprops(glcm)
stats =
Contrast: 2.8947
Correlation: 0.0783
Energy: 0.1191
Homogeneity: 0.5658
Perhaps you have some other definition - I don't know. After you read this, please clarify your definition of energy.
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Image Analyst
2017-9-11
I don't know what your vector represents. It might represent energy. Pixels are energy - just go back to first principles to work out the units.
(A watts /square meter) * (B square meters/pixel) * (C Joules/(Watt second)) * (D seconds exposure time) = Joules that are collected in a one pixel area during the exposure time. So gray levels is proportional to Joules.
Salma Hassan
2017-9-11
my feature vector was extracted by Discrete wavelet transform (DWT) as the paper in this link http://www.biomedres.info/biomedical-research/computer-aided-diagnostic-cad-for-feature-extraction-of-lungs-in-chest-radiograph-using-different-transform-features.html
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