Documentation

This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.

im2double

Convert image to double precision

Syntax

I2 = im2double(I)
I2 = im2double(I,'indexed')

Description

example

I2 = im2double(I) converts the intensity image I to double precision, rescaling the data if necessary. I can be a grayscale intensity image, a truecolor image, or a binary image.

If the input image is of class double, then the output image is identical.

I2 = im2double(I,'indexed') converts the indexed image I to double precision, offsetting the data if necessary.

Examples

collapse all

I = imread('peppers.png');
whos I
  Name        Size                Bytes  Class    Attributes

  I         384x512x3            589824  uint8              
I2 = im2double(I);
whos I2
  Name        Size                 Bytes  Class     Attributes

  I2        384x512x3            4718592  double              

Convert an array to class double on the GPU. This example requires the Parallel Computing Toolbox™.

I1 = gpuArray(reshape(uint8(linspace(1,255,25)),[5 5]));
I2 = im2double(I1);

Input Arguments

collapse all

Input image, specified as a scalar, vector, matrix, or multidimensional array.

  • If I is an intensity or truecolor image, it can be uint8, uint16, double, logical, single, or int16.

  • If I is an indexed image, it can be uint8, uint16, double or logical.

  • If I is a binary image, it must be logical.

If the Parallel Computing Toolbox is installed, I can be a gpuArray and im2double converts I on a GPU.

Data Types: single | double | int16 | uint8 | uint16 | logical

Tips

  • im2double supports the generation of efficient, production-quality C/C++ code if you have MATLAB® Coder™ installed.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

Was this topic helpful?