roicolor

Select region of interest (ROI) based on color

Description

example

BW = roicolor(I,low,high) returns an ROI selected as those pixels in image I that lie within the range [low high]. The returned value, BW, is a binary image with 0s outside the region of interest and 1s inside.

BW = roicolor(I,v) returns an ROI selected as those pixels in image I that match values in vector v.

Examples

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Load an indexed image X wth color map map. The color map has 128 colors. Display the indexed image.

load trees
imshow(X,map)

Create a binary mask image based on color. The mask is true for pixels with index in the range [10, 20]. The mask is false for pixels with index outside this range.

BW = roicolor(X,10,20);

Display the binary mask.

imshow(BW)

Input Arguments

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Indexed or grayscale image, specified as an m-by-n numeric matrix.

Minimum value to include in the ROI, specified as a numeric scalar.

Minimum value to include in the ROI, specified as a numeric scalar.

Set of values to include in the ROI, specified as a numeric vector.

Output Arguments

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Binary image, returned as an m-by-n logical matrix.

Data Types: logical

Tips

  • You can use the returned image as a mask for masked filtering using roifilt2.

  • If you specify a colormap range, [low high], then

    BW = (I >= low) & (I <= high)
  • If you specify a set of colormap values, v, then the mask generated by roicolor is equivalent to:

    BW = ismember(I,v)

Introduced before R2006a