MATLAB: Outline the shape in the image

contour

Hi,
I need to outline a shape with circle in the image. Here is the image which i created using colormap.
The condition is if the 0.6<pixel<1 , then outline it with a circle. where pixel is the pixel value which is ranged from 0.1 to 1.
Here is the image info
Filename: XXXXX
FileModDate: '31-May-2020 23:43:42'
FileSize: 1588399
Format: 'tif'
FormatVersion: []
Width: 840
Height: 630
BitDepth: 24
ColorType: 'truecolor'
FormatSignature: [73 73 42 0]
ByteOrder: 'little-endian'
NewSubFileType: 0
BitsPerSample: [8 8 8]
Compression: 'Uncompressed'
PhotometricInterpretation: 'RGB'
StripOffsets: [1×70 double]
SamplesPerPixel: 3
RowsPerStrip: 9
StripByteCounts: [1×70 double]
XResolution: 96
YResolution: 96
ResolutionUnit: 'Inch'
Colormap: []
PlanarConfiguration: 'Chunky'
TileWidth: []
TileLength: []
TileOffsets: []
TileByteCounts: []
Orientation: 1
FillOrder: 1
GrayResponseUnit: 0.0100
MaxSampleValue: [255 255 255]
MinSampleValue: [0 0 0]
Thresholding: 1
Offset: 1587608
ImageDescription: 'MATLAB Handle Graphics'

Best Answer

You can use bwboundaries() and plot():
binaryImage =  0.6 < grayImage & grayImage < 1;
boundaries = bwboundaries(binaryImage);
hold on;
for k = 1 : length(boundaries)
    thisBoundary = boundaries{k};
    x = thisBoundary(:, 2); % Column
    y = thisBoundary(:, 1); % Row
    plot(x, y, 'r-', 'LineWidth', 2);
end
Attach your array or image file if you need more help.
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