Determine a regions average in MATLAB

Question

I need some help with RGB capture in a image. I am using impixel to manualy get RGB from a picture, but i would like to create a grid of let\'s say 20x20 px boxes where it will

Answer 1

This is my complete code for automatic color grabing from pictures in folder. So the program asks you to chose a folder and after that you get a table full of information about color and roundess. I am using this code to get color from fruits that have white background . It does everything by itself. Hope it helps someone.

clear all;
clc;


uiwait(msgbox('Chose the folder where your pictures are kept. Click OK to continue..'));

% Opening the folder

folder = uigetdir(pwd); 
filePattern = fullfile(folder, '*.jpg');
jpegFiles = dir(filePattern);
    for k = 1:length(jpegFiles)
        baseFileName = jpegFiles(k).name;
        fullFileName = fullfile(folder, baseFileName);
        [pathstr, name, ext] = fileparts(fullFileName);
        naziv_voca=name;

        %Taking RGB color

        slika = imread(fullFileName);
        [redovi stupci RGBboje] = size(slika);
        red_ink = floor(redovi/10);
        stup_ink = floor(stupci/10);
        r = 1;
        c = 1;
        for stupac = 1 : stup_ink  : stupci
            for red = 1 : red_ink : redovi
            red1 = red;
            red2 = red1 + red_ink;
            stupac1 = stupac;
            stupac2 = stupac1 + stup_ink;
            red2 = min(red2, redovi);
            stupac2 = min(stupac2, stupci);
            crveniS = slika(red1:red2, stupac1:stupac2, 1);
            zeleniS = slika(red1:red2, stupac1:stupac2, 2);
            plaviS = slika(red1:red2, stupac1:stupac2, 3);
            crvena(r,c) = mean2(crveniS);
            zelena(r,c) = mean2(zeleniS);
            plava(r,c) = mean2(plaviS);
            r = r + 1;
                if r >redovi
                    r = 1;
                end
            end
            c = c + 1;
                if c >1
                    c = 1;
                end
            end

        RGB=[crvena,zelena,plava];
        bijela=[255 255 255];
        tolerancija = 50;
        rez = RGB((abs(RGB(:,1)-bijela(1)) > tolerancija) | (abs(RGB(:,2)-bijela(2)) > tolerancija),:);
        trez=round(rez); 


        %Taking shape

        pic = rgb2gray(slika);
        threshold = graythresh(pic);
        bw = im2bw(pic,threshold);
        fbw = ones(size(bw))-imfill(ones(size(bw))-bw); 
        invImg = ~fbw;
        f = bwlabel(invImg);
        S = regionprops(f,'Area','Perimeter','centroid');
        Thr=100;
        S=S([S.Area]>Thr);
        score = (min(sqrt([S.Area]),[S.Perimeter]/4)./(max(sqrt([S.Area]), [S.Perimeter]/4))).^2;
        score=max(score);

        %Inserting data into table and creating data

        if exist('tablica.mat','file')
            vel=size(trez,1);
            for z=1:vel
                s=load('tablica');
                olddata=s.data;
                temp=trez(z,:);
                dataCell= [naziv_voca,num2cell(temp),num2cell(score)]; 
                data=[olddata;dataCell];
                save('tablica.mat','-append','data');
            end
        else
            stupac_rgb = num2cell(trez,1);
            zstupac = cellfun(@sum,stupac_rgb); 
            zred = size(trez,1);           
            rez = bsxfun(@rdivide,zstupac,zred); 
            trez=round(rez);
            data= [naziv_voca,num2cell(trez),num2cell(score)];
            save('tablica','data')
        end 

    end  
    uiwait(msgbox('Your information is saved'));