jitterColorHSV

Randomly alter color of pixels

Syntax

J = jitterColorHSV(I,Name,Value)

Description

J = jitterColorHSV(I,Name,Value) adjusts the color of RGB image I with a randomly selected value of hue, saturation, brightness, and contrast from the HSV color space. Specify the range of each type of adjustment using name-value pair arguments.

Examples

Randomly Adjust Image Color

Read and display an image.

I = imread('kobi.png');
imshow(I)

Randomly adjust the hue, saturation, brightness, and contrast of the image. To demonstrate the randomness of the adjustment, repeat the operation on the original image three times.

J1 = jitterColorHSV(I,'Contrast',0.4,'Hue',0.1,'Saturation',0.2,'Brightness',0.3);
J2 = jitterColorHSV(I,'Contrast',0.4,'Hue',0.1,'Saturation',0.2,'Brightness',0.3);
J3 = jitterColorHSV(I,'Contrast',0.4,'Hue',0.1,'Saturation',0.2,'Brightness',0.3);

Display the adjusted images in a montage.

montage({J1,J2,J3},'Size',[1 3])

Input Arguments

I — RGB image

m-by-n-by-3 numeric array

RGB image with original pixel values, specified as an m-by-n-by-3 numeric array.

Data Types: single | double | uint8 | uint16

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: J = jitterColorHSV(I,'Hue',0.1)

'Hue' — Hue offset

0 (default) | numeric scalar | 2-element numeric vector

Hue offset, specified as the comma-separated pair consisting of 'Hue' and one of the following values. jitterColorHSV converts input RGB image I to the HSV color space before adding a random value to the hue channel of the image. jitterColorHSV circularly wraps the modified hue to the range [0, 1] before converting the jittered HSV image back to the RGB color space.

Value	Meaning
Numeric scalar in the range [0, 1]	Add random amount of hue from the uniform distribution [-Hue Hue]
2-element numeric vector with elements in the range [-1, 1]	Add a random amount of hue from a continuous uniform distribution within the specified interval. The second element must be larger than or equal to the first element.

Data Types: single | double

'Saturation' — Saturation offset

0 (default) | numeric scalar | 2-element numeric vector

Saturation offset, specified as the comma-separated pair consisting of 'Saturation' and one of the following values. jitterColorHSV converts input RGB image I to the HSV color space before adding a random value to the saturation channel of the image. jitterColorHSV clips the modified saturation to the range [0, 1] before converting the jittered HSV image back to the RGB color space.

Value	Meaning
Numeric scalar in the range [0, 1]	Add random amount of saturation from the uniform distribution [-Saturation Saturation]
2-element numeric vector with elements in the range [-1, 1]	Add a random amount of saturation from a continuous uniform distribution within the specified interval. The second element must be larger than or equal to the first element.

Data Types: single | double

'Brightness' — Brightness offset

0 (default) | numeric scalar | 2-element numeric vector

Brightness offset, specified as the comma-separated pair consisting of 'Brightness' and one of the following values. jitterColorHSV converts input RGB image I to the HSV color space before adding a random value to the brightness (value) channel of the image. jitterColorHSV clips the modified brightness to the range [0, 1] before converting the jittered HSV image back to the RGB color space.

Value	Meaning
Numeric scalar in the range [0, 1]	Add random amount of brightness from the uniform distribution [-Brightness Brightness]
2-element numeric vector with elements in the range [-1, 1]	Add a random amount of brightness from a continuous uniform distribution within the specified interval. The second element must be larger than or equal to the first element.

Data Types: single | double

'Contrast' — Contrast scale factor

0 (default) | positive number | 2-element numeric vector

Contrast scale factor, specified as the comma-separated pair consisting of 'Contrast' and one of the following values. jitterColorHSV converts input RGB image I to the HSV color space before scaling the brightness (value) channel of the image by a random factor. jitterColorHSV clips the modified brightness to the range [0, 1] before converting the jittered HSV image back to the RGB color space.

Value	Meaning
Positive number	Scale the brightness by a random factor from the uniform distribution [1-Contrast 1+Contrast]
2-element numeric vector of positive numbers	Scale the brightness by a random factor from the uniform distribution within the specified interval. The second element must be larger than or equal to the first element.

Data Types: single | double

Output Arguments

J — Jittered RGB image

numeric array

Jittered RGB image, returned as a numeric array of the same size and data type as the input image, I.

Data Types: single | double | uint8 | uint16

More About

HSV Color Space

The HSV color space defines the hue, saturation, and value (brightness) for each pixel, respectively, as described in the table.

Attribute	Description
Hue	Value from 0 to 1 that corresponds to the color’s position on a color wheel. As hue increases from 0 to 1, the color transitions from red to orange, yellow, green, cyan, blue, magenta, and finally back to red.
Saturation	Amount of hue or departure from neutral. 0 indicates a grayscale image and 1 indicates maximum saturation.
Value	Maximum value among the red, green, and blue components of a specific color.