6. Create a Binary Version of the Image :: Getting Started (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

6. Create a Binary Version of the Image

Create a binary version of the image by using thresholding. The function graythresh automatically computes an appropriate threshold to use to convert the grayscale image to binary. The im2bw function performs the conversion.

level = graythresh(I3);
bw = im2bw(I3,level); 
figure, imshow(bw)

Binary Version of the Image

The binary image bw returned by im2bw is of class logical, as can be seen in this call to whos. The Image Processing Toolbox uses logical arrays to represent binary images. For more information, see Binary Images.

```
whos
```

MATLAB responds with

Name                Size         Bytes  Class

I                 256x256        65536  uint8 array
I2                256x256        65536  uint8 array
I3                256x256        65536  uint8 array
background        256x256        65536  uint8 array
bw                256x256        65536  logical array
level               1x1              8  double array

Grand total is 327681 elements using 327688 bytes

5. Adjust the Contrast in the Processed Image 7. Determine the Number of Objects in the Image