Quadtree decomposition (Encoding) and Decoding of RGB Image: S=trimsparse(S) - File Exchange

Code covered by the BSD License

A =padtomakepowof2(A,varargin... % if required then add padvalue (defualt 0)
I=qtreedecode(S,values) % Decode QuadTree Represenation of Image given as Sparse matrix 'S' and
I=qtreergbdecode(S,valRGB) % Decode QuadTree date that is decomposed (encode) by qt3ddecom method
S=trimsparse(S) % trim sparse matrix by removing extra rows/columns that have all elements zeros.
[S,keys]=delsparsekeybyxANDy(...
[S,valRGB]=qt3ddecom(I,vararg... % This method uses three thresholds for red,green and blue blocks.
[b1r,b1c,b2r,b2c,b3r,b3c,b4r,... % The method uses three thresholds for red,green and blue blocks.
[b1r,b1c,b2r,b2c,b3r,b3c,b4r,... % given the size of rectangle (matrix end points), it split into four
avg=avgofmatblks(mat,i,j,w,h) % finds average of different blocks of input matrix
drawquadblocks(S) % draw square quad blocks of quadtree in eight basic colors.
fillrect_ulwh(ul,w,h,varargin... % fill the rectangle region specified by upper left corner width
flag=ispowerof2(n)
rgbimgnew =padrgbtomakepowof2... % if required then add padvalue (defualt 0)
var=converttoclass(var,type)
main.m
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from Quadtree decomposition (Encoding) and Decoding of RGB Image by Dr. Murtaza Khan
Quadtree decomposition (Encoding) and Decoding of RGB Image of size M-by-N-by-3.

S=trimsparse(S)
% % trim sparse matrix by removing extra rows/columns that have all elements zeros. function S=trimsparse(S) [i,j,v] = find(S); S=S(1:max(i),1:max(j));