Name

im2bw — Convert an image to binary by thresholding

Calling Sequence

BW = im2bw(Img, threshold [, maxvalue])
BW = im2bw(Index, map, threshold [, maxvalue])

Parameters

Img
M x N x 3 truecolor image or M x N grayscale intensity image.
Index, map
M x N indexed image and its M x 3 colormap.
maxvalue
the maximum value to assume Img can take. (Optional, defaults to 1)
threshold
the threshold level, between 0 to 1 (a ratio, like percentage). Pixels of the image that are higher or equal than the threshold are mapped to 1, while pixels that are strictly lower than the threshold are mapped to zero.
BW
Resultant black and white binary image.

Description

Function im2bw converts RGB images, indexed images and grayscale intensity images to binary, by thresholding. 

       initial_dir = PWD;
       chdir (SIPDIR + 'images');

       [Img,map] = imread('indian.bmp');
       xbasc()
       imshow(Img, map);
       bw = im2bw(Img, map,0.5);
       imshow(bw,2);
       bw = im2bw(Img, map,0.2);
       imshow(bw,2);

       chdir(initial_dir);

Authors

Ricardo Fabbri <ricardofabbri[at]users.sf.net>

Availability

The latest version of SIP can be found at

http://siptoolbox.sf.net

See Also

im2gray