Calculates histograms at every point in an array I.
The qth bin of each histogram contains the count of the number of locations in I that
have value in between edges(q)<=v< edges(q+1). HS(i,j,...,k,:) will contain the
histogram at location (i,j,...,k), as calculated by weighing values in I by placing
weightmask at that location. For example, if weightmask is ones(window_size) then the
histogram at every location will simply be a histogram of the pixels within that window.
See histc_1D for more details about edges and nbins.
The shape flag specifies what to do at boundaries. See convn_fast for
possible flags such as 'same', 'valid', 'full, or 'smooth'.
INPUTS
I - Array with integer values [see above]
edges - either nbins+1 length vector of quantization bounds, or nbins
weightmask - numeric array of weights, or cell array of seperable weight kernels
shape - [optional] 'valid', ['full'], 'same', or 'smooth'
OUTPUTS
HS - ~size(I)xQ array where each ~size(I) elt is a Q element
histogram (~size(I) because depends on val of shape)
EXAMPLE
load trees;
L = conv2(X, filter_DOG_2D(10,4,1,0), 'valid' );
f1=filter_gauss_1D([],5); HS1 = histc_image( L, 15, {f1,f1'}, 'same' );
f2=ones(1,15); HS2 = histc_image( L, 15, {f2,f2'}, 'same' );
figure(1); im(X); figure(2); im(L); figure(3); montage2(HS1,1,1);
figure(4); montage2(HS2,1,1); figure(5); montage2(HS1-HS2,1,1);
DATESTAMP
29-Sep-2005 2:00pm
See also ASSIGN2BINS, HISTC_1D