libcamera::ipa::AwbBayes Class Reference

Implementation of a bayesian auto white balance algorithm. More...

Inheritance diagram for libcamera::ipa::AwbBayes:

Collaboration diagram for libcamera::ipa::AwbBayes:

Public Member Functions
int	init (const ValueNode &tuningData) override
	Initialize the algorithm by parsing tuningData.
AwbImplementation::Result	calculateAwb (const AwbStats &stats, unsigned int lux, std::array< double, 2 > range) override
	Calculate AWB data from the given statistics.
std::optional< RGB< double > >	gainsFromColourTemperature (double temperatureK) override
	Compute white balance gains from a colour temperature.
Public Member Functions inherited from libcamera::ipa::AwbImplementation
virtual	~AwbImplementation ()=default
	Virtual class destructor.

Detailed Description

Implementation of a bayesian auto white balance algorithm.

In a bayesian AWB algorithm the auto white balance estimation is improved by taking the likelihood of a given lightsource based on the estimated lux level into account. E.g. If it is very bright we can assume that we are outside and that colour temperatures around 6500 are preferred.

The second part of this algorithm is the search for the most likely colour temperature. It is implemented in AwbBayes::coarseSearch() and in AwbBayes::fineSearch(). The search works very well without prior likelihoods and therefore the algorithm itself provides very good results even without prior likelihoods.

Member Function Documentation

calculateAwb()

AwbImplementation::Result libcamera::ipa::AwbBayes::calculateAwb ( const AwbStats &  stats, unsigned int  lux, std::array< double, 2 >  range  )

overridevirtual

Calculate AWB data from the given statistics.

Parameters

[in]	stats	The statistics to use for the calculation
[in]	lux	The lux value of the scene
[in]	range	The colour temperature search limits

Calculate an AwbResult object from the given statistics and lux value. A lux value of 0 means it is unknown or invalid and the algorithm shall ignore it.

Returns

The AWB result

Implements libcamera::ipa::AwbImplementation.

gainsFromColourTemperature()

std::optional< RGB< double > > libcamera::ipa::AwbBayes::gainsFromColourTemperature ( double  colourTemperature )

overridevirtual

Compute white balance gains from a colour temperature.

Parameters

[in]

colourTemperature

The colour temperature in Kelvin

Compute the white balance gains from a colourTemperature. This function does not take any statistics into account. It simply interpolates the colour gains curve on a new colour temperature.

Returns

The RGB gain values adjusted to temperatureK

Implements libcamera::ipa::AwbImplementation.

init()

int libcamera::ipa::AwbBayes::init ( const ValueNode &  tuningData )

overridevirtual

Initialize the algorithm by parsing tuningData.

Parameters

[in]

tuningData

Implements libcamera::ipa::AwbImplementation.

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

• src/ipa/libipa/awb_bayes.h
• src/ipa/libipa/awb_bayes.cpp