boofcv.alg.color

Class ColorHsv

java.lang.Object

boofcv.alg.color.ColorHsv

public class ColorHsv
extends java.lang.Object

Color conversion between RGB and HSV color spaces. HSV stands for Hue-Saturation-Value. "Hue" has a range of [0,2*PI] and "Saturation" has a range of [0,1], the two together represent the color. While "Value" has the same range as the input pixels and represents how light/dark the color is. Original algorithm taken from [1] and modified slightly.

NOTE: The hue is represented in radians instead of degrees, as is often done.
NOTE: Hue will be set to NaN if it is undefined. It is undefined when chroma is zero, which happens when the input color is a pure gray (e.g. same value across all color bands).

RGB to HSV:

 min = min(r,g,b)
 max = max(r,g,b)
 delta = max-min  // this is the chroma
 value = max

 if( max != 0 )
   saturation = delta/max
 else
   saturation = 0;
   hue = NaN

 if( r == max )
   hue = (g-b)/delta
 else if( g == max )
   hue = 2 + (b-r)/delta
 else
   hue = 4 + (r-g)/delta

 hue *= 60.0*PI/180.0
 if( hue < 0 )
   hue += 2.0*PI

 

[1] http://www.cs.rit.edu/~ncs/color/t_convert.html

Field Summary

Fields

Modifier and Type	Field and Description
static float	d60_F32
static double	d60_F64
static float	PI2_F32
static double	PI2_F64

Constructor Summary

Constructors

Constructor and Description
ColorHsv()

Method Summary

Modifier and Type	Method and Description
static void	hsvToRgb_F32(MultiSpectral<ImageFloat32> hsv, MultiSpectral<ImageFloat32> rgb) Converts an image from HSV into RGB.
static void	hsvToRgb(double h, double s, double v, double[] rgb) Convert HSV color into RGB color
static void	hsvToRgb(float h, float s, float v, float[] rgb) Convert HSV color into RGB color
static void	rgbToHsv_F32(MultiSpectral<ImageFloat32> rgb, MultiSpectral<ImageFloat32> hsv) Converts an image from RGB into HSV.
static void	rgbToHsv(double r, double g, double b, double[] hsv) Convert RGB color into HSV color
static void	rgbToHsv(float r, float g, float b, float[] hsv) Convert RGB color into HSV color

Methods inherited from class java.lang.Object

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

Field Detail

d60_F64

public static final double d60_F64

See Also:

Constant Field Values

d60_F32

public static final float d60_F32

See Also:

Constant Field Values

PI2_F64

public static final double PI2_F64

See Also:

Constant Field Values

PI2_F32

public static final float PI2_F32

See Also:

Constant Field Values

Constructor Detail

ColorHsv

public ColorHsv()

Method Detail

hsvToRgb

public static void hsvToRgb(double h,
                            double s,
                            double v,
                            double[] rgb)

Convert HSV color into RGB color

Parameters:

h - Hue [0,2*PI]

s - Saturation [0,1]

v - Value

rgb - (Output) RGB value

hsvToRgb

public static void hsvToRgb(float h,
                            float s,
                            float v,
                            float[] rgb)

Convert HSV color into RGB color

Parameters:

h - Hue [0,2*PI]

s - Saturation [0,1]

v - Value

rgb - (Output) RGB value

rgbToHsv

public static void rgbToHsv(double r,
                            double g,
                            double b,
                            double[] hsv)

Convert RGB color into HSV color

Parameters:

r - red

g - green

b - blue

hsv - (Output) HSV value.

rgbToHsv

public static void rgbToHsv(float r,
                            float g,
                            float b,
                            float[] hsv)

Convert RGB color into HSV color

Parameters:

r - red

g - green

b - blue

hsv - (Output) HSV value.

hsvToRgb_F32

public static void hsvToRgb_F32(MultiSpectral<ImageFloat32> hsv,
                                MultiSpectral<ImageFloat32> rgb)

Converts an image from HSV into RGB.

Parameters:

hsv - (Input) Image in HSV format

rgb - (Output) Image in RGB format

rgbToHsv_F32

public static void rgbToHsv_F32(MultiSpectral<ImageFloat32> rgb,
                                MultiSpectral<ImageFloat32> hsv)

Converts an image from RGB into HSV. Pixels must have a value within the range of [0,1].

Parameters:

rgb - (Input) Image in RGB format

hsv - (Output) Image in HSV format