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histo_vols − Compute 2D intensity histogram of 2 volumes |
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histo_vols [ -i signal_level ] [ -d ] volume1 volume2 [histogramfile] |
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Converts volume1 and volume2 to byteformat, and generates a 2D grey-level co-occurrence histogram from the grayscale intensities in the two volumes. The histogram is 256x256, x-axis is volume1 intensity, y-axis is volume2 intensity. If ’histogramfile’ is specified the histogram is saved as a 2D volume file, data type LONG. At the same time, several voxel similarity measures are computed. The program computes: mean square (a-b)^2 scaled mean square (a-b*k)^2 k=sqrt(Var(a)/Var(b)) entropy sum p(a,b) log p(a,b) mutual information sum p(a,b) log (p(a,b)/p(a)p(b)) where p(a,b) is the histogram normalized so that the sum over a and b is 1. |
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If -d is specified, the program writes out the computed similarity measures in a single row of text so that sequential calls may be concatenated into a matrix. |
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The input volumes must be 8 bit unsigned integer. VAPET, ANALYZE, and XPRIME file formats are supported. |
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Ulrik Kjems <uk@imm.dtu.dk> |
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gauss_vol(1), histo_vols(1), subsample(1), file2vapet(1), file2ana(1), file2xprime(1), headerinfo(1), resize_vol(1), convert_vol(1), covar(1), flip(1), region(1), compute_warp(1), warp_reslice(1), warp_reconcile(1), |