Image processing image color

Làm thế nào tôi có thể phát hiện đối tượng màu (đỏ xanh lục) trong ảnh cùng lúc bằng không gian HSV.

Cảm ơn bạn.

Answer 1

[Rahul]

Hi @ngo tung,

In order to detect colored objects from like the red and green objects from the provided figure using the HSV color space the following steps can be considered:

• Converting the Image to HSV color space uning 'rgb2hsv' function.
• Define color specific thresholdsholds.
• Color thresholding can be done using ‘Color Thresholder app’ or writing custom code.
• Apply the mask to the original image and extract specific colors using 'bsxfun' function.

Here is an example:

% Using 'rgb2hsv' to convert the image to HSV color space
hsvImage = rgb2hsv(image);

% Creating masks based on threshold values (Can be adjusted accordingly to requirement)
redMask = ((hsvImage(:,:,1) >= 0) & (hsvImage(:,:,1) <= 0.1) | (hsvImage(:,:,1) >= 0.9) & (hsvImage(:,:,1) <= 1)) & (hsvImage(:,:,2) >= 0.5) & (hsvImage(:,:,3) >= 0.5);
greenMask = (hsvImage(:,:,1) >= 0.25) & (hsvImage(:,:,1) <= 0.45) & (hsvImage(:,:,2) >= 0.5) & (hsvImage(:,:,3) >= 0.5);
combinedMask = redMask | greenMask;

% Applying the mask to the original image using 'bsxfun' function
outputImage = bsxfun(@times, image, cast(combinedMask, 'like', image));

imshow(outputImage);

Here is what the 'outputImage' looks like:

Refer to the following MathWorks documentations to know more:

'rgb2hsv': https://www.mathworks.com/help/releases/R2020a/matlab/ref/rgb2hsv.html

'Color Thresholder App': https://www.mathworks.com/help/releases/R2020a/images/ref/colorthresholder-app.html

'bsxfun': https://www.mathworks.com/help/releases/R2020a/matlab/ref/bsxfun.html

Thanks.