image processing crop along boundaries

Hi guys, I would like some tips to solve this problem. Thank for your help.

I have an image with some geometrical figures in it. I would like to obtain a new image with only the geometrical figures in it ( neglecting the backround). I also want to keep the intensity information of the starting image for the area inside the geometrical figures.

ps: i need to imbinarize the starting picture cause switching to gray image and thresholding the values doesn't work as desired.

I will attach my script.

Answer 1

[Image Analyst]

You forgot to attach tt so we can't see the image or the background. Please attach it. Is it being binarized properly?

You'll probably need to use "hold on" BEFORE you call plot so that you don't blow away the image.

And instead of axis square, you need to use

axis('on', 'image')

And I don't think the call to view() is needed.

Don't use image as the name of your variable since it's the name of a built-in function.

Finally you'll need to crop the image

    originalImage = imread('tt');
    hFig = figure
    h1 = subplot(1, 3, 1);
    imshow(originalImage);

    BW = imbinarize(originalImage);
    BW = bwareaopen(BW,500);         
    subplot(1, 3, 2);
    imshow(BW)

    % Make measurements.
    props = regionprops(BW, 'BoundingBox');
    B = bwboundaries(BW);
    hold(h1, 'on');
    for k=1:length(B)
          % Display boundary in red over the original image.
          boundary = B{k};
          subplot(1, 3, 1);
          plot(boundary(:,2), boundary(:,1), 'r-', 'LineWidth', 2);
          axis('on', 'image');
          
          % Display bounding box over image.
          thisBB = props(k).BoundingBox;
          rectangle('Position', thisBB, 'EdgeColor', 'y');

          % Get a cropped image.
          croppedImage = imcrop(originalImage, thisBB);
          % Display the cropped image.
          subplot(1, 3, 3);
          imshow(croppedImage);         
          drawnow;
          hFig.WindowState = 'maximized'
          pause(0.7);
    end

[Murstoe]

it works just fine! Thanks

Answer 2

[Aytaç Tok]

How can I get the object by auto cropping from a rgb picture. For example, there is a banana on the table and the background is black. I want to crop this picture and just take the banana and I want no background pixel at all. how can I do that

[Image Analyst]

Use the ColorThresholder app on the Apps tab of the tool ribbon.

[Aytaç Tok]

how can ı do that can u help me . can u share one example

[Image Analyst]

Try this

1. Click on the Apps tab ofthe tool ribbon
2. Look in the Image Processing section for the Color Thresholder and click on it.
3. Click the File Load menu and load your image from the file.
4. Select a color space, such as HSV.
5. Adjust the Value threshold to get just the banana.
6. If it doesn't work well, then try to involve the Hue channel as we..
7. Click the Export button to create a function for it.
8. In your program, read in your image and then call the function that you exported.