[v2,6/8] ipa: ipu3: Remove bespoke AGC functions from IPU3
diff mbox series

Message ID 20240417131536.484129-7-dan.scally@ideasonboard.com
State Superseded
Headers show
Series
  • Centralise Agc into libipa
Related show

Commit Message

Dan Scally April 17, 2024, 1:15 p.m. UTC
Now that the IPU3's Agc is derived from MeanLuminanceAgc we can
delete all the unecessary bespoke functions.

Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
---
Changes in v2:

	- Kept the documentation for estimateLuminance()

 src/ipa/ipu3/algorithms/agc.cpp | 227 +-------------------------------
 src/ipa/ipu3/algorithms/agc.h   |  13 --
 2 files changed, 3 insertions(+), 237 deletions(-)

Comments

Jacopo Mondi April 22, 2024, 10:36 a.m. UTC | #1
Hi Dan

On Wed, Apr 17, 2024 at 02:15:34PM +0100, Daniel Scally wrote:
> Now that the IPU3's Agc is derived from MeanLuminanceAgc we can
> delete all the unecessary bespoke functions.
>
> Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
> Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
> ---
> Changes in v2:
>
> 	- Kept the documentation for estimateLuminance()
>
>  src/ipa/ipu3/algorithms/agc.cpp | 227 +-------------------------------
>  src/ipa/ipu3/algorithms/agc.h   |  13 --
>  2 files changed, 3 insertions(+), 237 deletions(-)
>
> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
> index 3b9761bd..46fc3b33 100644
> --- a/src/ipa/ipu3/algorithms/agc.cpp
> +++ b/src/ipa/ipu3/algorithms/agc.cpp
> @@ -125,8 +125,6 @@ int Agc::configure(IPAContext &context,
>  	activeState.agc.gain = minAnalogueGain_;
>  	activeState.agc.exposure = 10ms / configuration.sensor.lineDuration;
>
> -	frameCount_ = 0;
> -
>  	context.activeState.agc.constraintMode = constraintModes().begin()->first;
>  	context.activeState.agc.exposureMode = exposureModeHelpers().begin()->first;
>
> @@ -139,42 +137,6 @@ int Agc::configure(IPAContext &context,
>  	return 0;
>  }
>
> -/**
> - * \brief Estimate the mean value of the top 2% of the histogram
> - * \param[in] stats The statistics computed by the ImgU
> - * \param[in] grid The grid used to store the statistics in the IPU3
> - * \return The mean value of the top 2% of the histogram
> - */
> -double Agc::measureBrightness(const ipu3_uapi_stats_3a *stats,
> -			      const ipu3_uapi_grid_config &grid) const
> -{
> -	/* Initialise the histogram array */
> -	uint32_t hist[knumHistogramBins] = { 0 };
> -
> -	for (unsigned int cellY = 0; cellY < grid.height; cellY++) {
> -		for (unsigned int cellX = 0; cellX < grid.width; cellX++) {
> -			uint32_t cellPosition = cellY * stride_ + cellX;
> -
> -			const ipu3_uapi_awb_set_item *cell =
> -				reinterpret_cast<const ipu3_uapi_awb_set_item *>(
> -					&stats->awb_raw_buffer.meta_data[cellPosition]
> -				);
> -
> -			uint8_t gr = cell->Gr_avg;
> -			uint8_t gb = cell->Gb_avg;
> -			/*
> -			 * Store the average green value to estimate the
> -			 * brightness. Even the overexposed pixels are
> -			 * taken into account.
> -			 */
> -			hist[(gr + gb) / 2]++;
> -		}
> -	}
> -
> -	/* Estimate the quantile mean of the top 2% of the histogram. */
> -	return Histogram(Span<uint32_t>(hist)).interQuantileMean(0.98, 1.0);
> -}
> -
>  Histogram Agc::parseStatistics(const ipu3_uapi_stats_3a *stats,
>  			       const ipu3_uapi_grid_config &grid)
>  {
> @@ -208,123 +170,9 @@ Histogram Agc::parseStatistics(const ipu3_uapi_stats_3a *stats,
>  	return Histogram(Span<uint32_t>(hist));
>  }
>
> -/**
> - * \brief Apply a filter on the exposure value to limit the speed of changes
> - * \param[in] exposureValue The target exposure from the AGC algorithm
> - *
> - * The speed of the filter is adaptive, and will produce the target quicker
> - * during startup, or when the target exposure is within 20% of the most recent
> - * filter output.
> - *
> - * \return The filtered exposure
> - */
> -utils::Duration Agc::filterExposure(utils::Duration exposureValue)
> -{
> -	double speed = 0.2;
> -
> -	/* Adapt instantly if we are in startup phase. */
> -	if (frameCount_ < kNumStartupFrames)
> -		speed = 1.0;
> -
> -	/*
> -	 * If we are close to the desired result, go faster to avoid making
> -	 * multiple micro-adjustments.
> -	 * \todo Make this customisable?
> -	 */
> -	if (filteredExposure_ < 1.2 * exposureValue &&
> -	    filteredExposure_ > 0.8 * exposureValue)
> -		speed = sqrt(speed);
> -
> -	filteredExposure_ = speed * exposureValue +
> -			    filteredExposure_ * (1.0 - speed);
> -
> -	LOG(IPU3Agc, Debug) << "After filtering, exposure " << filteredExposure_;
> -
> -	return filteredExposure_;
> -}
> -
> -/**
> - * \brief Estimate the new exposure and gain values
> - * \param[inout] frameContext The shared IPA frame Context
> - * \param[in] yGain The gain calculated based on the relative luminance target
> - * \param[in] iqMeanGain The gain calculated based on the relative luminance target
> - */
> -void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
> -			  double yGain, double iqMeanGain)
> -{
> -	const IPASessionConfiguration &configuration = context.configuration;
> -	/* Get the effective exposure and gain applied on the sensor. */
> -	uint32_t exposure = frameContext.sensor.exposure;
> -	double analogueGain = frameContext.sensor.gain;
> -
> -	/* Use the highest of the two gain estimates. */
> -	double evGain = std::max(yGain, iqMeanGain);
> -
> -	/* Consider within 1% of the target as correctly exposed */
> -	if (utils::abs_diff(evGain, 1.0) < 0.01)
> -		LOG(IPU3Agc, Debug) << "We are well exposed (evGain = "
> -				    << evGain << ")";
> -
> -	/* extracted from Rpi::Agc::computeTargetExposure */
> -
> -	/* Calculate the shutter time in seconds */
> -	utils::Duration currentShutter = exposure * configuration.sensor.lineDuration;
> -
> -	/*
> -	 * Update the exposure value for the next computation using the values
> -	 * of exposure and gain really used by the sensor.
> -	 */
> -	utils::Duration effectiveExposureValue = currentShutter * analogueGain;
> -
> -	LOG(IPU3Agc, Debug) << "Actual total exposure " << currentShutter * analogueGain
> -			    << " Shutter speed " << currentShutter
> -			    << " Gain " << analogueGain
> -			    << " Needed ev gain " << evGain;
> -
> -	/*
> -	 * Calculate the current exposure value for the scene as the latest
> -	 * exposure value applied multiplied by the new estimated gain.
> -	 */
> -	utils::Duration exposureValue = effectiveExposureValue * evGain;
> -
> -	/* Clamp the exposure value to the min and max authorized */
> -	utils::Duration maxTotalExposure = maxShutterSpeed_ * maxAnalogueGain_;
> -	exposureValue = std::min(exposureValue, maxTotalExposure);
> -	LOG(IPU3Agc, Debug) << "Target total exposure " << exposureValue
> -			    << ", maximum is " << maxTotalExposure;
> -
> -	/*
> -	 * Filter the exposure.
> -	 * \todo estimate if we need to desaturate
> -	 */
> -	exposureValue = filterExposure(exposureValue);
> -
> -	/*
> -	 * Divide the exposure value as new exposure and gain values.
> -	 *
> -	 * Push the shutter time up to the maximum first, and only then
> -	 * increase the gain.
> -	 */
> -	utils::Duration shutterTime =
> -		std::clamp<utils::Duration>(exposureValue / minAnalogueGain_,
> -					    minShutterSpeed_, maxShutterSpeed_);
> -	double stepGain = std::clamp(exposureValue / shutterTime,
> -				     minAnalogueGain_, maxAnalogueGain_);
> -	LOG(IPU3Agc, Debug) << "Divided up shutter and gain are "
> -			    << shutterTime << " and "
> -			    << stepGain;
> -}
> -
>  /**
>   * \brief Estimate the relative luminance of the frame with a given gain
> - * \param[in] frameContext The shared IPA frame context
> - * \param[in] grid The grid used to store the statistics in the IPU3
> - * \param[in] stats The IPU3 statistics and ISP results
> - * \param[in] gain The gain to apply to the frame
> - * \return The relative luminance
> - *
> - * This function estimates the average relative luminance of the frame that
> - * would be output by the sensor if an additional \a gain was applied.
> + * \param[in] gain The gain to apply in estimating luminance
>   *
>   * The estimation is based on the AWB statistics for the current frame. Red,
>   * green and blue averages for all cells are first multiplied by the gain, and
> @@ -339,42 +187,9 @@ void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
>   *
>   * More detailed information can be found in:
>   * https://en.wikipedia.org/wiki/Relative_luminance
> + *
> + * @return The relative luminance of the frame

While this is valid Doxygen, it's usually "\return"

With this fixed
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

Thanks
  j


>   */
> -double Agc::estimateLuminance(IPAActiveState &activeState,
> -			      const ipu3_uapi_grid_config &grid,
> -			      const ipu3_uapi_stats_3a *stats,
> -			      double gain)
> -{
> -	double redSum = 0, greenSum = 0, blueSum = 0;
> -
> -	/* Sum the per-channel averages, saturated to 255. */
> -	for (unsigned int cellY = 0; cellY < grid.height; cellY++) {
> -		for (unsigned int cellX = 0; cellX < grid.width; cellX++) {
> -			uint32_t cellPosition = cellY * stride_ + cellX;
> -
> -			const ipu3_uapi_awb_set_item *cell =
> -				reinterpret_cast<const ipu3_uapi_awb_set_item *>(
> -					&stats->awb_raw_buffer.meta_data[cellPosition]
> -				);
> -			const uint8_t G_avg = (cell->Gr_avg + cell->Gb_avg) / 2;
> -
> -			redSum += std::min(cell->R_avg * gain, 255.0);
> -			greenSum += std::min(G_avg * gain, 255.0);
> -			blueSum += std::min(cell->B_avg * gain, 255.0);
> -		}
> -	}
> -
> -	/*
> -	 * Apply the AWB gains to approximate colours correctly, use the Rec.
> -	 * 601 formula to calculate the relative luminance, and normalize it.
> -	 */
> -	double ySum = redSum * activeState.awb.gains.red * 0.299
> -		    + greenSum * activeState.awb.gains.green * 0.587
> -		    + blueSum * activeState.awb.gains.blue * 0.114;
> -
> -	return ySum / (grid.height * grid.width) / 255;
> -}
> -
>  double Agc::estimateLuminance(double gain)
>  {
>  	double redSum = 0, greenSum = 0, blueSum = 0;
> @@ -408,42 +223,6 @@ void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
>  		  const ipu3_uapi_stats_3a *stats,
>  		  ControlList &metadata)
>  {
> -	/*
> -	 * Estimate the gain needed to have the proportion of pixels in a given
> -	 * desired range. iqMean is the mean value of the top 2% of the
> -	 * cumulative histogram, and we want it to be as close as possible to a
> -	 * configured target.
> -	 */
> -	double iqMean = measureBrightness(stats, context.configuration.grid.bdsGrid);
> -	double iqMeanGain = kEvGainTarget * knumHistogramBins / iqMean;
> -
> -	/*
> -	 * Estimate the gain needed to achieve a relative luminance target. To
> -	 * account for non-linearity caused by saturation, the value needs to be
> -	 * estimated in an iterative process, as multiplying by a gain will not
> -	 * increase the relative luminance by the same factor if some image
> -	 * regions are saturated.
> -	 */
> -	double yGain = 1.0;
> -	double yTarget = kRelativeLuminanceTarget;
> -
> -	for (unsigned int i = 0; i < 8; i++) {
> -		double yValue = estimateLuminance(context.activeState,
> -						  context.configuration.grid.bdsGrid,
> -						  stats, yGain);
> -		double extraGain = std::min(10.0, yTarget / (yValue + .001));
> -
> -		yGain *= extraGain;
> -		LOG(IPU3Agc, Debug) << "Y value: " << yValue
> -				    << ", Y target: " << yTarget
> -				    << ", gives gain " << yGain;
> -		if (extraGain < 1.01)
> -			break;
> -	}
> -
> -	computeExposure(context, frameContext, yGain, iqMeanGain);
> -	frameCount_++;
> -
>  	Histogram hist = parseStatistics(stats, context.configuration.grid.bdsGrid);
>  	rGain_ = context.activeState.awb.gains.red;
>  	gGain_ = context.activeState.awb.gains.blue;
> diff --git a/src/ipa/ipu3/algorithms/agc.h b/src/ipa/ipu3/algorithms/agc.h
> index 40f32188..945d1846 100644
> --- a/src/ipa/ipu3/algorithms/agc.h
> +++ b/src/ipa/ipu3/algorithms/agc.h
> @@ -38,29 +38,16 @@ public:
>  		     ControlList &metadata) override;
>
>  private:
> -	double measureBrightness(const ipu3_uapi_stats_3a *stats,
> -				 const ipu3_uapi_grid_config &grid) const;
> -	utils::Duration filterExposure(utils::Duration currentExposure);
> -	void computeExposure(IPAContext &context, IPAFrameContext &frameContext,
> -			     double yGain, double iqMeanGain);
> -	double estimateLuminance(IPAActiveState &activeState,
> -				 const ipu3_uapi_grid_config &grid,
> -				 const ipu3_uapi_stats_3a *stats,
> -				 double gain);
>  	double estimateLuminance(double gain) override;
>  	Histogram parseStatistics(const ipu3_uapi_stats_3a *stats,
>  				  const ipu3_uapi_grid_config &grid);
>
> -	uint64_t frameCount_;
> -
>  	utils::Duration minShutterSpeed_;
>  	utils::Duration maxShutterSpeed_;
>
>  	double minAnalogueGain_;
>  	double maxAnalogueGain_;
>
> -	utils::Duration filteredExposure_;
> -
>  	uint32_t stride_;
>  	double rGain_;
>  	double gGain_;
> --
> 2.34.1
>

Patch
diff mbox series

diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
index 3b9761bd..46fc3b33 100644
--- a/src/ipa/ipu3/algorithms/agc.cpp
+++ b/src/ipa/ipu3/algorithms/agc.cpp
@@ -125,8 +125,6 @@  int Agc::configure(IPAContext &context,
 	activeState.agc.gain = minAnalogueGain_;
 	activeState.agc.exposure = 10ms / configuration.sensor.lineDuration;
 
-	frameCount_ = 0;
-
 	context.activeState.agc.constraintMode = constraintModes().begin()->first;
 	context.activeState.agc.exposureMode = exposureModeHelpers().begin()->first;
 
@@ -139,42 +137,6 @@  int Agc::configure(IPAContext &context,
 	return 0;
 }
 
-/**
- * \brief Estimate the mean value of the top 2% of the histogram
- * \param[in] stats The statistics computed by the ImgU
- * \param[in] grid The grid used to store the statistics in the IPU3
- * \return The mean value of the top 2% of the histogram
- */
-double Agc::measureBrightness(const ipu3_uapi_stats_3a *stats,
-			      const ipu3_uapi_grid_config &grid) const
-{
-	/* Initialise the histogram array */
-	uint32_t hist[knumHistogramBins] = { 0 };
-
-	for (unsigned int cellY = 0; cellY < grid.height; cellY++) {
-		for (unsigned int cellX = 0; cellX < grid.width; cellX++) {
-			uint32_t cellPosition = cellY * stride_ + cellX;
-
-			const ipu3_uapi_awb_set_item *cell =
-				reinterpret_cast<const ipu3_uapi_awb_set_item *>(
-					&stats->awb_raw_buffer.meta_data[cellPosition]
-				);
-
-			uint8_t gr = cell->Gr_avg;
-			uint8_t gb = cell->Gb_avg;
-			/*
-			 * Store the average green value to estimate the
-			 * brightness. Even the overexposed pixels are
-			 * taken into account.
-			 */
-			hist[(gr + gb) / 2]++;
-		}
-	}
-
-	/* Estimate the quantile mean of the top 2% of the histogram. */
-	return Histogram(Span<uint32_t>(hist)).interQuantileMean(0.98, 1.0);
-}
-
 Histogram Agc::parseStatistics(const ipu3_uapi_stats_3a *stats,
 			       const ipu3_uapi_grid_config &grid)
 {
@@ -208,123 +170,9 @@  Histogram Agc::parseStatistics(const ipu3_uapi_stats_3a *stats,
 	return Histogram(Span<uint32_t>(hist));
 }
 
-/**
- * \brief Apply a filter on the exposure value to limit the speed of changes
- * \param[in] exposureValue The target exposure from the AGC algorithm
- *
- * The speed of the filter is adaptive, and will produce the target quicker
- * during startup, or when the target exposure is within 20% of the most recent
- * filter output.
- *
- * \return The filtered exposure
- */
-utils::Duration Agc::filterExposure(utils::Duration exposureValue)
-{
-	double speed = 0.2;
-
-	/* Adapt instantly if we are in startup phase. */
-	if (frameCount_ < kNumStartupFrames)
-		speed = 1.0;
-
-	/*
-	 * If we are close to the desired result, go faster to avoid making
-	 * multiple micro-adjustments.
-	 * \todo Make this customisable?
-	 */
-	if (filteredExposure_ < 1.2 * exposureValue &&
-	    filteredExposure_ > 0.8 * exposureValue)
-		speed = sqrt(speed);
-
-	filteredExposure_ = speed * exposureValue +
-			    filteredExposure_ * (1.0 - speed);
-
-	LOG(IPU3Agc, Debug) << "After filtering, exposure " << filteredExposure_;
-
-	return filteredExposure_;
-}
-
-/**
- * \brief Estimate the new exposure and gain values
- * \param[inout] frameContext The shared IPA frame Context
- * \param[in] yGain The gain calculated based on the relative luminance target
- * \param[in] iqMeanGain The gain calculated based on the relative luminance target
- */
-void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
-			  double yGain, double iqMeanGain)
-{
-	const IPASessionConfiguration &configuration = context.configuration;
-	/* Get the effective exposure and gain applied on the sensor. */
-	uint32_t exposure = frameContext.sensor.exposure;
-	double analogueGain = frameContext.sensor.gain;
-
-	/* Use the highest of the two gain estimates. */
-	double evGain = std::max(yGain, iqMeanGain);
-
-	/* Consider within 1% of the target as correctly exposed */
-	if (utils::abs_diff(evGain, 1.0) < 0.01)
-		LOG(IPU3Agc, Debug) << "We are well exposed (evGain = "
-				    << evGain << ")";
-
-	/* extracted from Rpi::Agc::computeTargetExposure */
-
-	/* Calculate the shutter time in seconds */
-	utils::Duration currentShutter = exposure * configuration.sensor.lineDuration;
-
-	/*
-	 * Update the exposure value for the next computation using the values
-	 * of exposure and gain really used by the sensor.
-	 */
-	utils::Duration effectiveExposureValue = currentShutter * analogueGain;
-
-	LOG(IPU3Agc, Debug) << "Actual total exposure " << currentShutter * analogueGain
-			    << " Shutter speed " << currentShutter
-			    << " Gain " << analogueGain
-			    << " Needed ev gain " << evGain;
-
-	/*
-	 * Calculate the current exposure value for the scene as the latest
-	 * exposure value applied multiplied by the new estimated gain.
-	 */
-	utils::Duration exposureValue = effectiveExposureValue * evGain;
-
-	/* Clamp the exposure value to the min and max authorized */
-	utils::Duration maxTotalExposure = maxShutterSpeed_ * maxAnalogueGain_;
-	exposureValue = std::min(exposureValue, maxTotalExposure);
-	LOG(IPU3Agc, Debug) << "Target total exposure " << exposureValue
-			    << ", maximum is " << maxTotalExposure;
-
-	/*
-	 * Filter the exposure.
-	 * \todo estimate if we need to desaturate
-	 */
-	exposureValue = filterExposure(exposureValue);
-
-	/*
-	 * Divide the exposure value as new exposure and gain values.
-	 *
-	 * Push the shutter time up to the maximum first, and only then
-	 * increase the gain.
-	 */
-	utils::Duration shutterTime =
-		std::clamp<utils::Duration>(exposureValue / minAnalogueGain_,
-					    minShutterSpeed_, maxShutterSpeed_);
-	double stepGain = std::clamp(exposureValue / shutterTime,
-				     minAnalogueGain_, maxAnalogueGain_);
-	LOG(IPU3Agc, Debug) << "Divided up shutter and gain are "
-			    << shutterTime << " and "
-			    << stepGain;
-}
-
 /**
  * \brief Estimate the relative luminance of the frame with a given gain
- * \param[in] frameContext The shared IPA frame context
- * \param[in] grid The grid used to store the statistics in the IPU3
- * \param[in] stats The IPU3 statistics and ISP results
- * \param[in] gain The gain to apply to the frame
- * \return The relative luminance
- *
- * This function estimates the average relative luminance of the frame that
- * would be output by the sensor if an additional \a gain was applied.
+ * \param[in] gain The gain to apply in estimating luminance
  *
  * The estimation is based on the AWB statistics for the current frame. Red,
  * green and blue averages for all cells are first multiplied by the gain, and
@@ -339,42 +187,9 @@  void Agc::computeExposure(IPAContext &context, IPAFrameContext &frameContext,
  *
  * More detailed information can be found in:
  * https://en.wikipedia.org/wiki/Relative_luminance
+ *
+ * @return The relative luminance of the frame
  */
-double Agc::estimateLuminance(IPAActiveState &activeState,
-			      const ipu3_uapi_grid_config &grid,
-			      const ipu3_uapi_stats_3a *stats,
-			      double gain)
-{
-	double redSum = 0, greenSum = 0, blueSum = 0;
-
-	/* Sum the per-channel averages, saturated to 255. */
-	for (unsigned int cellY = 0; cellY < grid.height; cellY++) {
-		for (unsigned int cellX = 0; cellX < grid.width; cellX++) {
-			uint32_t cellPosition = cellY * stride_ + cellX;
-
-			const ipu3_uapi_awb_set_item *cell =
-				reinterpret_cast<const ipu3_uapi_awb_set_item *>(
-					&stats->awb_raw_buffer.meta_data[cellPosition]
-				);
-			const uint8_t G_avg = (cell->Gr_avg + cell->Gb_avg) / 2;
-
-			redSum += std::min(cell->R_avg * gain, 255.0);
-			greenSum += std::min(G_avg * gain, 255.0);
-			blueSum += std::min(cell->B_avg * gain, 255.0);
-		}
-	}
-
-	/*
-	 * Apply the AWB gains to approximate colours correctly, use the Rec.
-	 * 601 formula to calculate the relative luminance, and normalize it.
-	 */
-	double ySum = redSum * activeState.awb.gains.red * 0.299
-		    + greenSum * activeState.awb.gains.green * 0.587
-		    + blueSum * activeState.awb.gains.blue * 0.114;
-
-	return ySum / (grid.height * grid.width) / 255;
-}
-
 double Agc::estimateLuminance(double gain)
 {
 	double redSum = 0, greenSum = 0, blueSum = 0;
@@ -408,42 +223,6 @@  void Agc::process(IPAContext &context, [[maybe_unused]] const uint32_t frame,
 		  const ipu3_uapi_stats_3a *stats,
 		  ControlList &metadata)
 {
-	/*
-	 * Estimate the gain needed to have the proportion of pixels in a given
-	 * desired range. iqMean is the mean value of the top 2% of the
-	 * cumulative histogram, and we want it to be as close as possible to a
-	 * configured target.
-	 */
-	double iqMean = measureBrightness(stats, context.configuration.grid.bdsGrid);
-	double iqMeanGain = kEvGainTarget * knumHistogramBins / iqMean;
-
-	/*
-	 * Estimate the gain needed to achieve a relative luminance target. To
-	 * account for non-linearity caused by saturation, the value needs to be
-	 * estimated in an iterative process, as multiplying by a gain will not
-	 * increase the relative luminance by the same factor if some image
-	 * regions are saturated.
-	 */
-	double yGain = 1.0;
-	double yTarget = kRelativeLuminanceTarget;
-
-	for (unsigned int i = 0; i < 8; i++) {
-		double yValue = estimateLuminance(context.activeState,
-						  context.configuration.grid.bdsGrid,
-						  stats, yGain);
-		double extraGain = std::min(10.0, yTarget / (yValue + .001));
-
-		yGain *= extraGain;
-		LOG(IPU3Agc, Debug) << "Y value: " << yValue
-				    << ", Y target: " << yTarget
-				    << ", gives gain " << yGain;
-		if (extraGain < 1.01)
-			break;
-	}
-
-	computeExposure(context, frameContext, yGain, iqMeanGain);
-	frameCount_++;
-
 	Histogram hist = parseStatistics(stats, context.configuration.grid.bdsGrid);
 	rGain_ = context.activeState.awb.gains.red;
 	gGain_ = context.activeState.awb.gains.blue;
diff --git a/src/ipa/ipu3/algorithms/agc.h b/src/ipa/ipu3/algorithms/agc.h
index 40f32188..945d1846 100644
--- a/src/ipa/ipu3/algorithms/agc.h
+++ b/src/ipa/ipu3/algorithms/agc.h
@@ -38,29 +38,16 @@  public:
 		     ControlList &metadata) override;
 
 private:
-	double measureBrightness(const ipu3_uapi_stats_3a *stats,
-				 const ipu3_uapi_grid_config &grid) const;
-	utils::Duration filterExposure(utils::Duration currentExposure);
-	void computeExposure(IPAContext &context, IPAFrameContext &frameContext,
-			     double yGain, double iqMeanGain);
-	double estimateLuminance(IPAActiveState &activeState,
-				 const ipu3_uapi_grid_config &grid,
-				 const ipu3_uapi_stats_3a *stats,
-				 double gain);
 	double estimateLuminance(double gain) override;
 	Histogram parseStatistics(const ipu3_uapi_stats_3a *stats,
 				  const ipu3_uapi_grid_config &grid);
 
-	uint64_t frameCount_;
-
 	utils::Duration minShutterSpeed_;
 	utils::Duration maxShutterSpeed_;
 
 	double minAnalogueGain_;
 	double maxAnalogueGain_;
 
-	utils::Duration filteredExposure_;
-
 	uint32_t stride_;
 	double rGain_;
 	double gGain_;