[libcamera-devel,v2,10/13] ipa: ipu3: agc: Introduce previous exposure value

14217 diff mbox series

We need to calculate the gain on the previous exposure value calculated.
Now that we initialise the exposure and gain values in configure(), we
know the initial exposure value, and we can set it before any loop is
running.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
---
 src/ipa/ipu3/algorithms/agc.cpp | 13 +++++++++++--
 src/ipa/ipu3/algorithms/agc.h   |  1 +
 2 files changed, 12 insertions(+), 2 deletions(-)

Hi Jean-Michel,

Thank you for the patch.

On Wed, Oct 20, 2021 at 05:46:04PM +0200, Jean-Michel Hautbois wrote:
> We need to calculate the gain on the previous exposure value calculated.
> Now that we initialise the exposure and gain values in configure(), we
> know the initial exposure value, and we can set it before any loop is
> running.
> 
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
> ---
>  src/ipa/ipu3/algorithms/agc.cpp | 13 +++++++++++--
>  src/ipa/ipu3/algorithms/agc.h   |  1 +
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
> index eec77378..19f3a420 100644
> --- a/src/ipa/ipu3/algorithms/agc.cpp
> +++ b/src/ipa/ipu3/algorithms/agc.cpp
> @@ -42,7 +42,8 @@ static constexpr double kEvGainTarget = 0.5;
>  Agc::Agc()
>  	: frameCount_(0), lastFrame_(0), iqMean_(0.0), lineDuration_(0s),
>  	  minExposureLines_(0), maxExposureLines_(0), filteredExposure_(0s),
> -	  filteredExposureNoDg_(0s), currentExposure_(0s), currentExposureNoDg_(0s)
> +	  filteredExposureNoDg_(0s), currentExposure_(0s),
> +	  currentExposureNoDg_(0s), prevExposureValue_(0s)
>  {
>  }
>  
> @@ -58,9 +59,14 @@ int Agc::configure(IPAContext &context, const IPAConfigInfo &configInfo)
>  		context.configuration.agc.minAnalogueGain;
>  	context.frameContext.agc.exposure = minExposureLines_;
>  
> +	/* \todo replace the exposure in lines storage with time based ones */

This could have gone to an earlier patch.

>  	minExposureLines_ = context.configuration.agc.minShutterSpeed / lineDuration_;
>  	maxExposureLines_ = context.configuration.agc.maxShutterSpeed / lineDuration_;
>  
> +	prevExposureValue_ = context.frameContext.agc.gain
> +			   * context.frameContext.agc.exposure
> +			   * lineDuration_;
> +
>  	return 0;
>  }
>  
> @@ -146,7 +152,7 @@ void Agc::lockExposureGain(uint32_t &exposure, double &analogueGain)
>  				    << " Gain " << analogueGain
>  				    << " Needed ev gain " << evGain;
>  
> -		currentExposure_ = currentExposureNoDg_ * evGain;
> +		currentExposure_ = prevExposureValue_ * evGain;
>  		utils::Duration minShutterSpeed = minExposureLines_ * lineDuration_;
>  		utils::Duration maxShutterSpeed = maxExposureLines_ * lineDuration_;
>  
> @@ -175,6 +181,9 @@ void Agc::lockExposureGain(uint32_t &exposure, double &analogueGain)
>  
>  		exposure = shutterTime / lineDuration_;
>  		analogueGain = stepGain;
> +
> +		/* Update the exposure value for the next process call */

		/*
		 * Update the exposure value for the next process call.
		 *
		 * \todo Obtain the values of the exposure time and analog gain
		 * that were actually used by the sensor, either from embedded
		 * data when available, or from the delayed controls
		 * infrastructure in case a slow down caused a mismatch.
		 */

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +		prevExposureValue_ = shutterTime * analogueGain;
>  	}
>  	lastFrame_ = frameCount_;
>  }
> diff --git a/src/ipa/ipu3/algorithms/agc.h b/src/ipa/ipu3/algorithms/agc.h
> index cd26d08c..2ae88e9f 100644
> --- a/src/ipa/ipu3/algorithms/agc.h
> +++ b/src/ipa/ipu3/algorithms/agc.h
> @@ -49,6 +49,7 @@ private:
>  	utils::Duration filteredExposureNoDg_;
>  	utils::Duration currentExposure_;
>  	utils::Duration currentExposureNoDg_;
> +	utils::Duration prevExposureValue_;
>  
>  	uint32_t stride_;
>  };