boofcv.alg.color

Class ColorYuv

java.lang.Object

boofcv.alg.color.ColorYuv

public class ColorYuv
extends java.lang.Object

Color conversion between YUV and RGB, and YCbCr and RGB. YUV is color encoding which takes in account a human perception model and is commonly used in cameras/video with analog signals. YCbCr is the digital equivalent color space of YUV that is scaled and offset. YCbCr is also commonly referred to as YUV, even though it is a different format.

Y component encodes luma (B&W gray scale) and U,V encodes color. The same is true for Y,Cb,Cr, respectively. In the functions below, if the input is floating point then YUV is used, otherwise YCbCr is used. How these color formats are encoded varies widely. For YCbCr, Y is "defined to have a nominal 8-bit range of 16-235, Cb and Cr are defined to have a nominal range of 16-240", see [2].

Equations:

 Y =  0.299*R + 0.587*G + 0.114*B
 U = -0.147*R - 0.289*G + 0.436*B = 0.492*(B - Y)
 V =  0.615*R - 0.515*G - 0.100*B = 0.877*(R - Y)

Source: [1] and [2].

Citations:

1. http://software.intel.com/sites/products/documentation/hpc/ipp/ippi/ippi_ch6/ch6_color_models.html
2. Keith Jack, "Video Demystified" 5th ed 2007

Constructor Summary

Constructors

Constructor and Description
ColorYuv()

Method Summary

Modifier and Type	Method and Description
static void	rgbToYCbCr(int r, int g, int b, byte[] yuv) Conversion from RGB to YCbCr.
static void	rgbToYuv_F32(Planar<GrayF32> rgb, Planar<GrayF32> yuv) Convert a 3-channel Planar image from RGB into YUV.
static void	rgbToYuv(double r, double g, double b, double[] yuv) Conversion from RGB to YUV using same equations as Intel IPP.
static void	rgbToYuv(float r, float g, float b, float[] yuv) Conversion from RGB to YUV using same equations as Intel IPP.
static void	ycbcrToRgb_U8(Planar<GrayU8> yuv, Planar<GrayU8> rgb) Conversion from YCbCr to RGB.
static void	ycbcrToRgb(int y, int cb, int cr, byte[] rgb) Conversion from YCbCr to RGB.
static void	yuvToRgb_F32(Planar<GrayF32> yuv, Planar<GrayF32> rgb) Convert a 3-channel Planar image from YUV into RGB.
static void	yuvToRgb(double y, double u, double v, double[] rgb) Conversion from YUV to RGB using same equations as Intel IPP.
static void	yuvToRgb(float y, float u, float v, float[] rgb) Conversion from YUV to RGB using same equations as Intel IPP.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ColorYuv

public ColorYuv()

Method Detail

rgbToYuv

public static void rgbToYuv(double r,
                            double g,
                            double b,
                            double[] yuv)

Conversion from RGB to YUV using same equations as Intel IPP.

rgbToYuv

public static void rgbToYuv(float r,
                            float g,
                            float b,
                            float[] yuv)

Conversion from RGB to YUV using same equations as Intel IPP.

yuvToRgb

public static void yuvToRgb(double y,
                            double u,
                            double v,
                            double[] rgb)

Conversion from YUV to RGB using same equations as Intel IPP.

yuvToRgb

public static void yuvToRgb(float y,
                            float u,
                            float v,
                            float[] rgb)

Conversion from YUV to RGB using same equations as Intel IPP.

rgbToYCbCr

public static void rgbToYCbCr(int r,
                              int g,
                              int b,
                              byte[] yuv)

Conversion from RGB to YCbCr. See [Jack07].

Parameters:

r - Red [0 to 255]

g - Green [0 to 255]

b - Blue [0 to 255]

ycbcrToRgb

public static void ycbcrToRgb(int y,
                              int cb,
                              int cr,
                              byte[] rgb)

Conversion from YCbCr to RGB. See [Jack07].

Parameters:

y - Y [0 to 255]

cb - Cb [0 to 255]

cr - Cr [0 to 255]

yuvToRgb_F32

public static void yuvToRgb_F32(Planar<GrayF32> yuv,
                                Planar<GrayF32> rgb)

Convert a 3-channel Planar image from YUV into RGB.

Parameters:

rgb - (Input) RGB encoded image

yuv - (Output) YUV encoded image

rgbToYuv_F32

public static void rgbToYuv_F32(Planar<GrayF32> rgb,
                                Planar<GrayF32> yuv)

Convert a 3-channel Planar image from RGB into YUV. NOTE: Input and output image can be the same instance.

Parameters:

rgb - (Input) RGB encoded image

yuv - (Output) YUV encoded image

ycbcrToRgb_U8

public static void ycbcrToRgb_U8(Planar<GrayU8> yuv,
                                 Planar<GrayU8> rgb)

Conversion from YCbCr to RGB. NOTE: Input and output image can be the same instance.

Parameters:

yuv - YCbCr encoded 8-bit image

rgb - RGB encoded 8-bit image