MATLAB: I exactly want to do same thing explained in “what should I do so that only gray image converts into binary , not the black backgroung while moving the threshold.” question. But when I count white and black pixels in ROI I am getting 0.

Question

I exactly want to do same thing explained in "what should I do so that only gray image converts into binary , not the black background while moving the threshold." question. But when I count white and black pixels in ROI I am getting 0.

Following is my code.

if true
   close all;
   clear all;
   %Read image in Matlab
   ReadImg = imread('Sanjivjadhv25rckd.jpg');
   figure(1); imshow(ReadImg);title('Original Image');
   %Convert image into Gray Image
   GrayImg = rgb2gray(ReadImg);
   figure(2); imshow(GrayImg);title('Gray Image');
   %ROI selection manually
   height = 254   %189;
   width = 254   %229;
   [col1, row1] = ginput(1);
   row2 = row1 + height;
   col2 = col1 + width;
   CropedImg = ReadImg(row1:row2, col1:col2);
   figure(3); imshow(CropedImg); title('Region of Intrest');
   %Removal of spekel noise using Median filter
   medianFilteredIm2 = medfilt2(CropedImg,[4,4]);%using [4,4] window size getting better results
   %figure(3); imshow(medianFilteredIm1);title('output of median filter');
   figure(4); imshow(medianFilteredIm2);title('output of median filter');
   %Segmentation of Kidney part using imfreehand
   h = imfreehand();
   mask = createMask(h);
   medianFilteredIm2(~mask) = 0;
   figure(5); imshow(medianFilteredIm2);
   GrayThresh = 0.4; %graythresh(medianFilteredIm2);
   BinaryImg = im2bw(medianFilteredIm2,GrayThresh);
   figure(10); imshow(BinaryImg);title('Binary Image');
   filledBinaryImage = imfill(BinaryImg, 'holes');
   pixelsInROI = medianFilteredIm2(filledBinaryImage);
   numBlackPixels = sum(pixelsInROI == 0);
   numWhitePixels = sum(pixelsInROI == 255);
end

Following are images.

https://plus.google.com/photos/111799079095235591256/albums/5982916654912559041?hl=en_US

Answer 1

I don't understand the question you quoted (due to bad grammar), and don't understand yours either. But I think you want this:

numWhitePixels = sum(filledBinaryImage(:));
numBlackPixels = numel(filledBinaryImage) - numWhitePixels ;