roifilt2 (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Filter a region of interest in an image

Syntax

J = roifilt2(h,I,BW)
J = roifilt2(I,BW,fun)

Description

J = roifilt2(h,I,BW) filters the data in I with the two-dimensional linear filter h. BW is a binary image the same size as I that is used as a mask for filtering. roifilt2 returns an image that consists of filtered values for pixels in locations where BW contains 1's, and unfiltered values for pixels in locations where BW contains 0's. For this syntax, roifilt2 calls filter2 to implement the filter.

J = roifilt2(I,BW,fun) processes the data in I using the function fun. The result J contains computed values for pixels in locations where BW contains 1's, and the actual values in I for pixels in locations where BW contains 0's.

fun must be a function handle.

Class Support

For the syntax that includes a filter h, the input image can be logical or numeric, and the output array J has the same class as the input image. For the syntax that includes a function, I can be of any class supported by fun, and the class of J depends on the class of the output from fun.

Example

This example continues the roipoly example.

I = imread('eight.tif');
c = [222 272 300 270 221 194];
r = [21 21 75 121 121 75];
BW = roipoly(I,c,r);
h = fspecial('unsharp');
J = roifilt2(h,I,BW);
imshow(J), figure, imshow(J)

roifill roipoly