immultiply (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Multiply two images, or multiply an image by a constant

Syntax

```
Z = immultiply(X,Y)
```

Description

Z = immultiply(X,Y) multiplies each element in array X by the corresponding element in array Y and returns the product in the corresponding element of the output array Z.

If X and Y are real numeric arrays with the same size and class, then Z has the same size and class as X. If X is a numeric array and Y is a scalar double, then Z has the same size and class as X.

If X is logical and Y is numeric, then Z has the same size and class as Y. If X is numeric and Y is logical, then Z has the same size and class as X.

immultiply computes each element of Z individually in double-precision floating point. If X is an integer array, then elements of Z exceeding the range of the integer type are truncated, and fractional values are rounded.

Note On Intel architecture processors, immultiply can take advantage of the Intel Performance Primitives Library (IPPL), thus accelerating its execution time. IPPL is activated only if arrays X, Y, and Z are of class logical, uint8, or single, and are of the same class.

Example

Multiply an image by itself. Note how the example converts the class of the image from uint8 to uint16 before performing the multiplication to avoid truncating the results.

I = imread('moon.tif');
I16 = uint16(I);
J = immultiply(I16,I16);
imshow(I), figure, imshow(J)

Scale an image by a constant factor:

I = imread('moon.tif');
J = immultiply(I,0.5);
subplot(1,2,1), imshow(I)
subplot(1,2,2), imshow(J)

See also

imabsdiff, imadd, imcomplement, imdivide, imlincomb, imsubtract, ippl

immovie imnoise