alvar::IntegralImage Class Reference

IntegralImage is used for calculating rectangular image sums and averages rapidly More...

#include <IntegralImage.h>

List of all members.

Public Member Functions
double	GetAve (CvRect &rect)
	Calculate the average for the given rectangular area in the image.
void	GetSubimage (const CvRect &rect, IplImage *sub)
	Get a sub-image using integral image representation.
double	GetSum (CvRect &rect, int *count=0)
	Calculate the sum for the given rectangular area in the image.
	IntegralImage ()
void	Update (IplImage *gray)
	Update integral image for the given image.
	~IntegralImage ()
Private Attributes
IplImage *	sum

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Detailed Description

IntegralImage is used for calculating rectangular image sums and averages rapidly

The integral images are based on making intermediate representation of the image. Using this approach the sum/average of rectangular area can be calculated using only four references for the integral image. The integral images are commonly used with HAAR-like features.

The IntegralImage should be used when we need to a lot of sum/average calculations for the same image.

References

• Konstantinos G. Derpanis (2007). Integral image-based representations. Department of Computer Science and Engineering, York University.
• Viola, P. & Jones, M. (2001). Rapid object detection using a boosted cascade of simple features. In IEEE Computer Vision and Pattern Recognition (pp. I:511-518).

Examples:

SampleIntegralImage.cpp.

Definition at line 100 of file IntegralImage.h.

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Constructor & Destructor Documentation

alvar::IntegralImage::IntegralImage

(

)

Definition at line 66 of file IntegralImage.cpp.

alvar::IntegralImage::~IntegralImage

(

)

Definition at line 69 of file IntegralImage.cpp.

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Member Function Documentation

double alvar::IntegralImage::GetAve

(

CvRect &

rect

)

Calculate the average for the given rectangular area in the image.

Definition at line 103 of file IntegralImage.cpp.

void alvar::IntegralImage::GetSubimage	(	const CvRect &	rect,
		IplImage *	sub
	)

Get a sub-image using integral image representation.

Parameters:

rect	The rectangle we want to get the sub-image from
sub	The image where the sub-image is generated. Note, the desired resolution is defined by sub.

Get an image sub with a predefined resolution from the given rectangular area rect . In practice the sub is filled by getting the average with GetAve() for every pixel area.

Examples:

SampleIntegralImage.cpp.

Definition at line 107 of file IntegralImage.cpp.

double alvar::IntegralImage::GetSum	(	CvRect &	rect,
		int *	count = 0
	)

Calculate the sum for the given rectangular area in the image.

Parameters:

rect	The rectancle
count	If this parameter is not 0 it is filled with number of pixels in the rectangle.

Definition at line 83 of file IntegralImage.cpp.

void alvar::IntegralImage::Update

(

IplImage *

gray

)

Update integral image for the given image.

Parameters:

gray	The original grayscale image we want analyze

Examples:

SampleIntegralImage.cpp.

Definition at line 72 of file IntegralImage.cpp.

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Member Data Documentation

IplImage* alvar::IntegralImage::sum [private]

Definition at line 101 of file IntegralImage.h.

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The documentation for this class was generated from the following files:

• IntegralImage.h
• IntegralImage.cpp