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rgb2ycbcr

Convert RGB color values to YCbCr color space

Description

example

YCBCR = rgb2ycbcr(RGB) converts the red, green, and blue values of an RGB image to luminance (Y) and chrominance (Cb and Cr) values of a YCbCr image.

Examples

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Convert Image from RGB to YCbCr

Read an RGB image into the workspace.

RGB = imread('board.tif');

Convert the image to YCbCr.

YCBCR = rgb2ycbcr(RGB);

Display the original image and the new image

figure
imshow(RGB);
title('Image in RGB Color Space');

Figure contains an axes. The axes with title Image in RGB Color Space contains an object of type image.

figure
imshow(YCBCR);
title('Image in YCbCr Color Space');

Figure contains an axes. The axes with title Image in YCbCr Color Space contains an object of type image.

Convert Colormap from RGB to YCbCr.

Load an indexed image into the workspace. The colormap is in RGB colorspace.

[I,map] = imread('forest.tif');

Convert the colormap to YCbCr.

newmap = rgb2ycbcr(map);

Display the grayscale image with the original map and with the new map.

figure
imshow(I,map)
title('Indexed Image with RGB Colormap');

Figure contains an axes. The axes with title Indexed Image with RGB Colormap contains an object of type image.

figure
imshow(I,newmap)
title('Indexed Image with YCbCr Colormap');

Figure contains an axes. The axes with title Indexed Image with YCbCr Colormap contains an object of type image.

Input Arguments

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RGB color values to convert, specified as a numeric array in one of these formats.

  • c-by-3 colormap. Each row specifies one RGB color value.

  • m-by-n-by-3 image

Data Types: single | double | uint8 | uint16

Output Arguments

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Converted YCbCr color values, returned as a numeric array of the same size as the input.

  • If the input is double or single, then Y is in the range [16/255, 235/255] and Cb and Cr are in the range [16/255, 240/255].

  • If the input is uint8, then Y is in the range [16, 235] and Cb and Cr are in the range [16, 240].

  • If the input is uint16, then Y is in the range [4112, 60395] and Cb and Cr are in the range [4112, 61680].

References

[1] Poynton, C. A.A Technical Introduction to Digital Video, John Wiley & Sons, Inc., 1996, p. 175.

[2] Rec. ITU-R BT.601-5, Studio Encoding Parameters of Digital Television for Standard 4:3 and Wide-screen 16:9 Aspect Ratios, (1982-1986-1990-1992-1994-1995), Section 3.5.

Extended Capabilities

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

Introduced before R2006a