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authorDavid Plowman <david.plowman@raspberrypi.com>2023-07-28 14:36:59 +0100
committerKieran Bingham <kieran.bingham@ideasonboard.com>2023-09-04 17:47:35 +0100
commit84b6327789fcf5be37a990d5be27f305e8514621 (patch)
tree1884f3a18cbcb48275d75247ef2d5c17f372f290 /src
parent2ea57d0b7702efb6e290f7ec2ef35b5646f91a6c (diff)
ipa: rpi: agc: Filter exposures before dealing with digital gain
We now time-filter the exposure before sorting out how much digital gain is required. This is actually a little more natural and simplifies the code. It also prepares us for some future work where this arrangement will be helpful. Signed-off-by: David Plowman <david.plowman@raspberrypi.com> Reviewed-by: Naushir Patuck <naush@raspberrpyi.com> Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Diffstat (limited to 'src')
-rw-r--r--src/ipa/rpi/controller/rpi/agc.cpp30
-rw-r--r--src/ipa/rpi/controller/rpi/agc.h2
2 files changed, 6 insertions, 26 deletions
diff --git a/src/ipa/rpi/controller/rpi/agc.cpp b/src/ipa/rpi/controller/rpi/agc.cpp
index e8526355..6087fc60 100644
--- a/src/ipa/rpi/controller/rpi/agc.cpp
+++ b/src/ipa/rpi/controller/rpi/agc.cpp
@@ -469,14 +469,14 @@ void Agc::process(StatisticsPtr &stats, Metadata *imageMetadata)
computeGain(stats, imageMetadata, gain, targetY);
/* Now compute the target (final) exposure which we think we want. */
computeTargetExposure(gain);
+ /* The results have to be filtered so as not to change too rapidly. */
+ filterExposure();
/*
* Some of the exposure has to be applied as digital gain, so work out
* what that is. This function also tells us whether it's decided to
* "desaturate" the image more quickly.
*/
bool desaturate = applyDigitalGain(gain, targetY);
- /* The results have to be filtered so as not to change too rapidly. */
- filterExposure(desaturate);
/*
* The last thing is to divide up the exposure value into a shutter time
* and analogue gain, according to the current exposure mode.
@@ -757,12 +757,12 @@ bool Agc::applyDigitalGain(double gain, double targetY)
if (desaturate)
dg /= config_.fastReduceThreshold;
LOG(RPiAgc, Debug) << "Digital gain " << dg << " desaturate? " << desaturate;
- target_.totalExposureNoDG = target_.totalExposure / dg;
- LOG(RPiAgc, Debug) << "Target totalExposureNoDG " << target_.totalExposureNoDG;
+ filtered_.totalExposureNoDG = filtered_.totalExposure / dg;
+ LOG(RPiAgc, Debug) << "Target totalExposureNoDG " << filtered_.totalExposureNoDG;
return desaturate;
}
-void Agc::filterExposure(bool desaturate)
+void Agc::filterExposure()
{
double speed = config_.speed;
/*
@@ -774,7 +774,6 @@ void Agc::filterExposure(bool desaturate)
speed = 1.0;
if (!filtered_.totalExposure) {
filtered_.totalExposure = target_.totalExposure;
- filtered_.totalExposureNoDG = target_.totalExposureNoDG;
} else {
/*
* If close to the result go faster, to save making so many
@@ -785,26 +784,7 @@ void Agc::filterExposure(bool desaturate)
speed = sqrt(speed);
filtered_.totalExposure = speed * target_.totalExposure +
filtered_.totalExposure * (1.0 - speed);
- /*
- * When desaturing, take a big jump down in totalExposureNoDG,
- * which we'll hide with digital gain.
- */
- if (desaturate)
- filtered_.totalExposureNoDG =
- target_.totalExposureNoDG;
- else
- filtered_.totalExposureNoDG =
- speed * target_.totalExposureNoDG +
- filtered_.totalExposureNoDG * (1.0 - speed);
}
- /*
- * We can't let the totalExposureNoDG exposure deviate too far below the
- * total exposure, as there might not be enough digital gain available
- * in the ISP to hide it (which will cause nasty oscillation).
- */
- if (filtered_.totalExposureNoDG <
- filtered_.totalExposure * config_.fastReduceThreshold)
- filtered_.totalExposureNoDG = filtered_.totalExposure * config_.fastReduceThreshold;
LOG(RPiAgc, Debug) << "After filtering, totalExposure " << filtered_.totalExposure
<< " no dg " << filtered_.totalExposureNoDG;
}
diff --git a/src/ipa/rpi/controller/rpi/agc.h b/src/ipa/rpi/controller/rpi/agc.h
index 939f9729..b7122de3 100644
--- a/src/ipa/rpi/controller/rpi/agc.h
+++ b/src/ipa/rpi/controller/rpi/agc.h
@@ -93,8 +93,8 @@ private:
void computeGain(StatisticsPtr &statistics, Metadata *imageMetadata,
double &gain, double &targetY);
void computeTargetExposure(double gain);
+ void filterExposure();
bool applyDigitalGain(double gain, double targetY);
- void filterExposure(bool desaturate);
void divideUpExposure();
void writeAndFinish(Metadata *imageMetadata, bool desaturate);
libcamera::utils::Duration limitShutter(libcamera::utils::Duration shutter);