[libcamera-devel] [PATCH v3 03/14] ipa: ipu3: Use sensor controls to update frameContext

Jean-Michel Hautbois jeanmichel.hautbois at ideasonboard.com
Thu Nov 11 14:51:19 CET 2021



On 11/11/2021 14:13, Kieran Bingham wrote:
> Quoting Jean-Michel Hautbois (2021-11-11 11:05:54)
>> The pipeline handler populates the new sensorControls ControlList, to
>> have the effective exposure and gain values for the current frame. This
>> is done when a statistics buffer is received.
>>
>> Make those values the frameContext::sensor values for the frame when the
>> EventStatReady event is received.
>>
>> AGC also needs to use frameContext.sensor as its input values and
>> frameContext.agc as its output values. Modify computeExposure by passing
>> it the frameContext instead of individual exposure and gain values.
>>
>> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
>> ---
>>   src/ipa/ipu3/algorithms/agc.cpp | 19 ++++++++++---------
>>   src/ipa/ipu3/algorithms/agc.h   |  2 +-
>>   src/ipa/ipu3/ipa_context.cpp    | 11 +++++++++++
>>   src/ipa/ipu3/ipa_context.h      |  5 +++++
>>   src/ipa/ipu3/ipu3.cpp           |  4 ++++
>>   5 files changed, 31 insertions(+), 10 deletions(-)
>>
>> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
>> index b5d736c1..825b35d4 100644
>> --- a/src/ipa/ipu3/algorithms/agc.cpp
>> +++ b/src/ipa/ipu3/algorithms/agc.cpp
>> @@ -169,10 +169,9 @@ void Agc::filterExposure()
>>   
>>   /**
>>    * \brief Estimate the new exposure and gain values
>> - * \param[inout] exposure The exposure value reference as a number of lines
>> - * \param[inout] gain The gain reference to be updated
>> + * \param[inout] frameContext The shared IPA frame Context
>>    */
>> -void Agc::computeExposure(uint32_t &exposure, double &analogueGain)
>> +void Agc::computeExposure(IPAFrameContext &frameContext)
>>   {
>>          /* Algorithm initialization should wait for first valid frames */
>>          /* \todo - have a number of frames given by DelayedControls ?
>> @@ -189,6 +188,10 @@ void Agc::computeExposure(uint32_t &exposure, double &analogueGain)
>>                  return;
>>          }
>>   
>> +       /* Get the effective exposure and gain applied on the sensor. */
>> +       uint32_t &exposure = frameContext.sensor.exposure;
>> +       double &analogueGain = frameContext.sensor.gain;
> 
> I don't think these need to be references now, but it doesn't
> particularly matter.
> 
> Perhaps removing the & would make it clear that the
> frameContext.sensor.exposure and frameContext.sensor.gain isn't going to
> be modified in this function (which the & could otherwise imply).
> 
> 
>> +
>>          /* Estimate the gain needed to have the proportion wanted */
>>          double evGain = kEvGainTarget * knumHistogramBins / iqMean_;
>>   
>> @@ -233,8 +236,9 @@ void Agc::computeExposure(uint32_t &exposure, double &analogueGain)
>>                              << shutterTime << " and "
>>                              << stepGain;
>>   
>> -       exposure = shutterTime / lineDuration_;
>> -       analogueGain = stepGain;
>> +       /* Update the estimated exposure and gain. */
>> +       frameContext.agc.exposure = shutterTime / lineDuration_;
>> +       frameContext.agc.gain = stepGain;
>>   
>>          /*
>>           * Update the exposure value for the next process call.
>> @@ -257,11 +261,8 @@ void Agc::computeExposure(uint32_t &exposure, double &analogueGain)
>>    */
>>   void Agc::process(IPAContext &context, const ipu3_uapi_stats_3a *stats)
>>   {
>> -       /* Get the latest exposure and gain applied */
>> -       uint32_t &exposure = context.frameContext.agc.exposure;
>> -       double &analogueGain = context.frameContext.agc.gain;
>>          measureBrightness(stats, context.configuration.grid.bdsGrid);
>> -       computeExposure(exposure, analogueGain);
>> +       computeExposure(context.frameContext);
> 
> That's a lot cleaner...
> 
>>          frameCount_++;
>>   }
>>   
>> diff --git a/src/ipa/ipu3/algorithms/agc.h b/src/ipa/ipu3/algorithms/agc.h
>> index 69e0b831..f0db25ee 100644
>> --- a/src/ipa/ipu3/algorithms/agc.h
>> +++ b/src/ipa/ipu3/algorithms/agc.h
>> @@ -34,7 +34,7 @@ private:
>>          void measureBrightness(const ipu3_uapi_stats_3a *stats,
>>                                 const ipu3_uapi_grid_config &grid);
>>          void filterExposure();
>> -       void computeExposure(uint32_t &exposure, double &gain);
>> +       void computeExposure(IPAFrameContext &frameContext);
>>   
>>          uint64_t frameCount_;
>>          uint64_t lastFrame_;
>> diff --git a/src/ipa/ipu3/ipa_context.cpp b/src/ipa/ipu3/ipa_context.cpp
>> index 2355a9c7..a7ff957d 100644
>> --- a/src/ipa/ipu3/ipa_context.cpp
>> +++ b/src/ipa/ipu3/ipa_context.cpp
>> @@ -119,6 +119,17 @@ namespace libcamera::ipa::ipu3 {
>>    * \brief White balance gain for B channel
>>    */
>>   
>> +/**
>> + * \var IPAFrameContext::sensor
>> + * \brief Effective sensor values
>> + *
>> + * \var IPAFrameContext::sensor.exposure
>> + * \brief Exposure time expressed as a number of lines
>> + *
>> + * \var IPAFrameContext::sensor.gain
>> + * \brief Analogue gain multiplier
>> + */
>> +
>>   /**
>>    * \var IPAFrameContext::toneMapping
>>    * \brief Context for ToneMapping and Gamma control
>> diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
>> index 1e46c61a..a5a19800 100644
>> --- a/src/ipa/ipu3/ipa_context.h
>> +++ b/src/ipa/ipu3/ipa_context.h
>> @@ -47,6 +47,11 @@ struct IPAFrameContext {
>>                  } gains;
>>          } awb;
>>   
>> +       struct {
>> +               uint32_t exposure;
>> +               double gain;
>> +       } sensor;
>> +
>>          struct {
>>                  double gamma;
>>                  struct ipu3_uapi_gamma_corr_lut gammaCorrection;
>> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
>> index bcc3863b..dee002a5 100644
>> --- a/src/ipa/ipu3/ipu3.cpp
>> +++ b/src/ipa/ipu3/ipu3.cpp
>> @@ -549,6 +549,10 @@ void IPAIPU3::processEvent(const IPU3Event &event)
>>                  const ipu3_uapi_stats_3a *stats =
>>                          reinterpret_cast<ipu3_uapi_stats_3a *>(mem.data());
>>   
>> +               /* \todo move those into processControls ? */
> 
> I still haven't understood why we want to move these into
> processControls.
> 
> I think that is supposed to deal with processing controls from the
> Request?
> 

That is more a question, I will remove it as a comment for the series, 
and if it appears later we need to move those then it will answer the 
question :-).

> For everything else
> 
> 
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> 
>> +               context_.frameContext.sensor.exposure = event.sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
>> +               context_.frameContext.sensor.gain = camHelper_->gain(event.sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
>> +
>>                  parseStatistics(event.frame, event.frameTimestamp, stats);
>>                  break;
>>          }
>> -- 
>> 2.32.0
>>


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