image processing

ive managed to successfully use variables and measure the perimeter of 2 images i have scanned from my flat bed scanner refer : http://www.mathworks.com/matlabcentral/answers/5133-image-processing-calculate-perimeter however now my question is to combine this as a program in which i can scan the images and compare. image uploading has already been completed in .net . now from the database i need to access these images and calculate their perimeters individually . how do i do this. any other questions do let me know. a recap : need to write an individual program to read the scanned images into the code and calculate their perimeters respectilvely thanks

Answer 1

[Vidhi Agarwal]

Hi Prashan,

I understand your query regarding a program with which you can scan the image, compare them and find the perimeters individually. Below are the steps that can help you in getting started assuming you have access to the images stored in a database and can retrieve them using MATLAB.

1. Use MATLAB's database toolbox to connect to your database and retrieve the images.
2. Convert the image to binary and use edge detection to find boundaries and calculate the perimeter of detected edges.

Below is the sample code:

% Step 1: Connect to the database and retrieve images
conn = database('your_database_name', 'username', 'password');
sqlquery = 'SELECT image_column FROM your_table';
curs = exec(conn, sqlquery);
curs = fetch(curs);
close(curs);
close(conn);

% Assuming the images are stored as binary blobs, convert them to MATLAB images
images = cell(size(curs.Data, 1), 1);
for i = 1:length(images)
    images{i} = imread(curs.Data{i});
end

% Step 2: Calculate the perimeters
perimeters = zeros(length(images), 1);

for i = 1:length(images)
    img = images{i};
    
    % Convert to grayscale if necessary
    if size(img, 3) == 3
        img = rgb2gray(img);
    end
    
    % Convert to binary image
    bw = imbinarize(img);
    
    % Find edges
    edges = edge(bw, 'Canny');
    
    % Calculate perimeter
    perimeters(i) = sum(edges(:));
end

% Step 3: Compare perimeters
disp('Perimeters of the images:');
disp(perimeters);

% Example comparison (e.g., difference between first two images)
if length(perimeters) >= 2
    perimeter_diff = abs(perimeters(1) - perimeters(2));
    fprintf('Difference between the perimeters of the first two images: %f\n', perimeter_diff);
end

For more understanding about database toolbox in MATLAB, refer to the following documentation:

1. https://www.mathworks.com/products/database.html

And for edge detection refer to the following documentation:

1. https://www.mathworks.com/help/images/edge-detection.html

Hope that helps!

[Image Analyst]

There is no need to read all the images into memory. If there are lots of images, that will simply use up all available memory. Better to process them one at a time using dir

Answer 2

[Image Analyst]

To process a series of image files, see the FAQ:

Process a sequence of files