getrangefromclass

Default display range of image based on its class

Syntax

range = getrangefromclass(I)

Description

range = getrangefromclass(I) returns the default display range of the image I based on its class type.

Examples

Get Default Display Range of Image

Read a sample image of data type uint8.

Im = imread('peppers.png');
imshow(Im)

Get the display range from the image. Images of type uint8 have pixel values in the range [0, 255].

rangeIm = getrangefromclass(Im)

rangeIm = 1×2

     0   255

Convert the image from type uint8 to type double.

RGB = im2double(Im);

Get the display range of the new image. The pixel values are in the range [0, 1], which is consistent with how the MATLAB® software interprets images of type double.

rangeRGB = getrangefromclass(RGB)

rangeRGB = 1×2

     0     1

Input Arguments

I — Input image

numeric array | logical array

Input image, specified as a numeric array or logical array.

Output Arguments

range — Display range

2-element numeric vector

Display range, returned as a 2-element numeric vector of the form [min max].

• For single and double data, getrangefromclass returns the range [0 1] to be consistent with the way MATLAB^® software interprets images of type double and single.

• For integer data, getrangefromclass returns the minimum and maximum representable values for that integer class. For example, if the class is uint8, the dynamic range is [0 255].

• For logical data, getrangefromclass returns the range [0 1].

Data Types: double

Extended Capabilities

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

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™. (since R2025a)

The getrangefromclass function fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray (Parallel Computing Toolbox). For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Version History

Introduced before R2006a