Matlab image processing issue

[MohamedX17]

I am not sure whether this is the right section or not
Recently I've started to self study Image processing using matlab for more precision I am trying to do chroma keying the two pictures in the attachment and here is my code

clc
clear
close all
rgb = imread('ninjagreen.jpg');
rgb=double(rgb)/255;
inds=((rgb(:,:,2)<=.58));
rgb(:,:,1)=rgb(:,:,1).*inds;
rgb(:,:,2)=rgb(:,:,2).*inds;
rgb(:,:,3)=rgb(:,:,3).*inds;
image(rgb)
red=rgb(:,:,1);
green=rgb(:,:,2);
blue=rgb(:,:,3);
redin=find(red~=0);
greenin=find(green~=0);
bluein=find(blue~=0);
forest=imread('forest.jpg');
forest=double(forest)/255;
forest_R=forest(:,:,1);
forest_G=forest(:,:,2);
forest_B=forest(:,:,3);
forest_R(redin)=red(redin);
forest_G(greenin)=green(greenin);
forest_B(bluein)=blue(bluein);
forest(:,:,1)=forest_R;
forest(:,:,2)=forest_G;
forest(:,:,3)=forest_B;
image(forest)

There is a problem in the matrix re-sizing so any idea how to fix that and Thanks in advance.

 

[weetabixharry]

First of all, your code formatting is terrible. Space it out. Use comments. Try something like this:

close all; clear all; clc;

% --- Load NINJA image ---
rgb = imread('ninjagreen.jpg');
rgb = double(rgb)/255;

% Blacken all pixels with green > 0.58
inds = rgb(:,:,2) <= .58;
rgb(:,:,1) = rgb(:,:,1).*inds;
rgb(:,:,2) = rgb(:,:,2).*inds;
rgb(:,:,3) = rgb(:,:,3).*inds;

% Display modified image
image(rgb);

% Extract red, green and blue components
red = rgb(:,:,1);
green = rgb(:,:,2);
blue = rgb(:,:,3);

% Get indices of pixels with non-zero r, g and b
redin = find(red~=0);
greenin = find(green~=0);
bluein = find(blue~=0);


% --- Load FOREST image ---
forest = imread('forest.jpg');
forest = double(forest)/255;

% Extract red, green and blue components
forest_R = forest(:,:,1);
forest_G = forest(:,:,2);
forest_B = forest(:,:,3);

% ??? Index the forest image with ninja image's non-zero r, g and b ??? 
forest_R(redin) = red(redin);
forest_G(greenin) = green(greenin);
forest_B(bluein) = blue(bluein);

% Copy results back to image data
forest(:,:,1) = forest_R;
forest(:,:,2) = forest_G;
forest(:,:,3) = forest_B;

% Display modified image
image(forest)

The first problem is that you are indexing the "forest" image with values obtained from the "ninja" image. This is probably not what you mean to do. What are you trying to do?

 

[Nic Teo]

HI,

I would like to rescale a disparity depth map results based on the requirements from Middlebury website (https://vision.middlebury.edu/stereo/submit/) from the range of 4 to 16. Below is the coding of a stereo matching algorithm i applied on a pair of stereo images

a = vision.ImageDataTypeConverter; %creates the object converts the input image to a single precision data type.
b = vision.ColorSpaceConverter('Conversion','RGB to intensity');
leftI3 = step(a,imread('venusl.ppm')); % step = step response of dynamic system
leftI = step(b,leftI3);
rightI3 = step(a,imread('venusr.ppm'));
rightI = step(b,rightI3);

%*******************************************************************Basic_Block_Matching******************************************************************************************************
Dbasic = zeros(size(leftI), 'single');
disparityRange = 30;
% Selects (2*halfBlockSize+1)-by-(2*halfBlockSize+1) block
halfBlockSize = 3;
blockSize = 2*halfBlockSize+1; %7X7 block
% Allocate space for all template matcher System objects.
tmats = cell(blockSize);

% Initialize progress bar
hWaitBar = waitbar(0, 'Performing basic block matching...');
nRowsLeft = size(leftI, 1); 

% Scan over all rows.
for m=1:nRowsLeft
    % Set min/max row bounds for image block.
    minr = max(1,m-halfBlockSize);
    maxr = min(nRowsLeft,m+halfBlockSize);
    % Scan over all columns.
    for n=1:size(leftI,2)
        minc = max(1,n-halfBlockSize);
        maxc = min(size(leftI,2),n+halfBlockSize);
        % Compute disparity bounds.
        mind = max( -disparityRange, 1-minc );
        maxd = min( disparityRange, size(leftI,2)-maxc );

        % Construct template and region of interest.
        template = rightI(minr:maxr,minc:maxc);
        templateCenter = floor((size(template)+1)/2);
        roi = [minc+templateCenter(2)+mind-1 ...
               minr+templateCenter(1)-1 ...
               maxd-mind+1 1];
        % Lookup proper TemplateMatcher object; create if empty.
        if isempty(tmats{size(template,1),size(template,2)})
            tmats{size(template,1),size(template,2)} = ...
                vision.TemplateMatcher('ROIInputPort',true);
        end
        thisTemplateMatcher = tmats{size(template,1),size(template,2)};

        % Run TemplateMatcher object.
        loc = step(thisTemplateMatcher, leftI, template, roi);
        Dbasic(m,n) = loc(1) - roi(1) + mind;
    end
    waitbar(m/nRowsLeft,hWaitBar);
end

close(hWaitBar);

figure(3), clf;
imshow(Dbasic,[]), axis image, colormap('jet'), colorbar;
caxis([0 disparityRange]);
title('Depth map from basic block matching');

%********************************************************************************************************************************

What should i add in the coding to rescale the the depth map of figure(3) and save is as a file?
Please help, thanks a lot!!

 

[u7karsh]

https://www.mathworks.in/help/images/ref/imresize.html

https://www.mathworks.in/help/matlab/ref/imwrite.html