i have a binary image , in that i used roifilt2 to filter ROI , i need to calculate the black pixels in the filtered region?

in one binary image i have to select different regions and count the black pixels in that particular region. i have applied roifilt2 to filter the specific region of interest.now i need to calculate the black pixels in each region separatelyw should i calculate?

Answer 1

[Tejas]

Hello Priya,

To determine the number of black pixels, the 'sum' function can be utilized. This function calculates the sum of elements within an array. For more details on this function, refer to this documentation: https://www.mathworks.com/help/matlab/ref/double.sum.html .

Here are the steps to find the number of black pixels within a region of interest:

• I am assuming, that you have applied the filter using the syntax shown below.

    filteredImage = roifilt2(h, Image, ROI); 

• Identify the indexes of black pixels within the region of interest using the code snippet below.

    blackPixelsIndexes = filteredImage(ROI) == 0; 

• Use the 'sum' function to calculate the total count of black pixels, as demonstrated in the following code snippet.

    numBlackPixelsRoi = sum(blackPixelsIndexes);