boofcv.alg.background

Interface BackgroundAlgorithmGaussian

All Known Implementing Classes:

BackgroundMovingGaussian, BackgroundMovingGaussian_IL, BackgroundMovingGaussian_MS, BackgroundMovingGaussian_SB, BackgroundStationaryGaussian, BackgroundStationaryGaussian_IL, BackgroundStationaryGaussian_MS, BackgroundStationaryGaussian_SB

public interface BackgroundAlgorithmGaussian

Performs background subtraction on a moving image by modeling each pixel as an independent Guassian distribution. For computational efficiency each band is modeled as having a diagonal covariance matrix with off diagonal terms set to zero. This model is susceptible to

By assuming that off diagonal terms are zero that's the same as assuming that all bands are independent distribution. This is an approximation but according to several papers it doesn't hurt performance much but simplifies computations significantly.

Internally the mean and variance are stored in ImageFloat32 images. This allows for the mean and variance of each pixel to be interpolated, reducing artifacts along the border of objects.

Tuning Parameters:

• learnRate: Specifies how fast it will adapt. 0 to 1, inclusive. 0 = static 1.0 = instant. Try 0.05
• threshold: Pixel's with a Mahalanobis distance <= threshold are assumed to be background. Consult a Chi-Squared table for theoretical values. 1-band try 10. 3-bands try 20.
• initial variance The initial variance assigned to pixels when they are first observed. By default this is Float.MIN_VALUE.

Method Summary

Modifier and Type	Method and Description
float	getInitialVariance() Returns the initial variance assigned to a pixel
float	getLearnRate() Returns the learning rate.
float	getMinimumDifference()
float	getThreshold()
void	setInitialVariance(float initialVariance) Sets the initial variance assigned to a pixel
void	setLearnRate(float learnRate) Specifies the learning rate
void	setMinimumDifference(float minimumDifference)
void	setThreshold(float threshold)

Method Detail

getInitialVariance

float getInitialVariance()

Returns the initial variance assigned to a pixel

Returns:

initial variance

setInitialVariance

void setInitialVariance(float initialVariance)

Sets the initial variance assigned to a pixel

Parameters:

initialVariance - initial variance

getLearnRate

float getLearnRate()

Returns the learning rate.

Returns:

0 (slow) to 1 (fast)

setLearnRate

void setLearnRate(float learnRate)

Specifies the learning rate

Parameters:

learnRate - 0 (slow) to 1 (fast)

getThreshold

float getThreshold()

setThreshold

void setThreshold(float threshold)

getMinimumDifference

float getMinimumDifference()

setMinimumDifference

void setMinimumDifference(float minimumDifference)