The default luminance threshold of im2bw is not optimal for most images. If you want to use a threshold appropriate for your image, you must compute the level using graythresh before calling im2bw.
See Also
Representing images - Representing text, images and sound - KS3 Computer Science Revision - BBC Bitesize[Solved] How many binary numbers are created with 8 bits?8 in Binary - How to Convert 8 from Decimal to Binary?Glossary - Binary ImagesIn R2016a, the imbinarize function was introduced. This function computes the luminance threshold and performs binarization in one step. imbinarize has additional benefits, such as the ability to perform adaptive thresholding when the image has nonuniform shading. For more information, see Image Binarization - New 2016a Functions.
The table shows some typical usages of im2bw and how to update your code to use imbinarize instead.
| Not Recommended | Recommended |
|---|---|
BW = im2bw(I); | BW = imbinarize(I,0.5); |
thresh = graythresh(I);BW = im2bw(I,thresh); | BW = imbinarize(I); |
There are no plans to remove im2bw at this time.
