
Re: DIVIDING AN IMAGE INTO SUB BLOCKS
Posted:
Feb 17, 2012 11:45 PM


"Matt J" wrote in message <jh6c9n$dtn$1@newscl01ah.mathworks.com>... > "sanyukta " <sanyuktachetia01@gmail.com> wrote in message <jh66hs$rnc$1@newscl01ah.mathworks.com>... > > ImageAnalyst <imageanalyst@mailinator.com> wrote in message <0bc34147dd8c44bbad0aaacfefac0ebf@g27g2000yqa.googlegroups.com>... > > > On Feb 10, 12:44 pm, "sanyukta " <sanyuktacheti...@gmail.com> wrote: > > > > Thanks..I have used mat2cell function and got a total of p=25 blocks.So each block has q=100x100 elements.Next,I want to concatenate all the elements of the block to give a vector to represent one block resulting in a matrix x=[x1,x2,....xp]of size qxp.How to do? > > > > > >  > > > If I understand you correctly you want to take one particular block > > > and concatenate all the elements of that block go give a 1D vector. > > > To do that you just do: > > > > > > m = rand(500,500); % Sample data 500x500 > > > divisions = [100 100 100 100 100]; > > > % Chop up into 100x100 cells. > > > mCell = mat2cell(m, divisions, divisions) > > > % Pull out one particular cell  it will be a 100x100 array. > > > thisBlock = mCell{2,4}; % Or whatever indexes you want. > > > % Concatenate into vector 10000 elements long. > > > columnVector = thisBlock(:); > > Thanks..I used the following code: > > clc; > > clear all; > > close all; > > a=imread('glyoxylase.jpg'); > > a1=rgb2gray(a); > > a2=mat2cell(a1,[100 100 100 100 100],[100 100 100 100 100]); > > disp(a2); > > > > I got the results of a2 as > > > > Columns 1 through 4 > > > > [100x100 uint8] [100x100 uint8] [100x100 uint8] [100x100 uint8] > > [100x100 uint8] [100x100 uint8] [100x100 uint8] [100x100 uint8] > > [100x100 uint8] [100x100 uint8] [100x100 uint8] [100x100 uint8] > > [100x100 uint8] [100x100 uint8] [100x100 uint8] [100x100 uint8] > > [100x100 uint8] [100x100 uint8] [100x100 uint8] [100x100 uint8] > > > > Column 5 > > > > [100x100 uint8] > > [100x100 uint8] > > [100x100 uint8] > > [100x100 uint8] > > [100x100 uint8] > > Means I got a total of 25 blocks.Next I want to concatenate all the elements of the 25 blocks to get a single vector. > ================= > > But what we can't understand is how the vector elements are supposed to be ordered. For example, one way you could have obtained a vector is simply to > do a2=a1(:). No need to convert to a cell at all. Well,i am going to do local processing on the image and feed the single vector in the self organizing map as input.As such I have converted the matrix into cell.Can you tell me how to create a 2D self organizing map?I want to create a self organizing map of size 5x5.But i am not able to do it.Please help me if you have any idea.

