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authorDavid Plowman <david.plowman@raspberrypi.com>2021-07-18 19:51:25 +0100
committerKieran Bingham <kieran.bingham@ideasonboard.com>2021-08-05 16:49:33 +0100
commitabaa45d627122205e838b1bd1f8c621efba2bbb0 (patch)
treeb853a20a9c1b4a5c119fe7a7939e26874e5f4458 /src/ipa/raspberrypi/controller/rpi/agc.cpp
parentd0c429c34cd37b16facaf8df0bf74614c83f5f75 (diff)
ipa: raspberrypi: AGC: handle modes with different sensitivities
When the sensor is switched to a mode with a different sensitivity, the target exposure values need to be adjusted proportionately to maintain the same image brightness. Signed-off-by: David Plowman <david.plowman@raspberrypi.com> Reviewed-by: Naushir Patuck <naush@raspberrypi.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Diffstat (limited to 'src/ipa/raspberrypi/controller/rpi/agc.cpp')
-rw-r--r--src/ipa/raspberrypi/controller/rpi/agc.cpp27
1 files changed, 22 insertions, 5 deletions
diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
index f57783f8..1cfdd3bb 100644
--- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
@@ -163,7 +163,7 @@ Agc::Agc(Controller *controller)
: AgcAlgorithm(controller), metering_mode_(nullptr),
exposure_mode_(nullptr), constraint_mode_(nullptr),
frame_count_(0), lock_count_(0),
- last_target_exposure_(0s),
+ last_target_exposure_(0s), last_sensitivity_(0.0),
ev_(1.0), flicker_period_(0s),
max_shutter_(0s), fixed_shutter_(0s), fixed_analogue_gain_(0.0)
{
@@ -268,9 +268,12 @@ void Agc::SetConstraintMode(std::string const &constraint_mode_name)
constraint_mode_name_ = constraint_mode_name;
}
-void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
+void Agc::SwitchMode(CameraMode const &camera_mode,
Metadata *metadata)
{
+ /* AGC expects the mode sensitivity always to be non-zero. */
+ ASSERT(camera_mode.sensitivity);
+
housekeepConfig();
Duration fixed_shutter = clipShutter(fixed_shutter_);
@@ -292,9 +295,20 @@ void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
filtered_.shutter = fixed_shutter;
filtered_.analogue_gain = fixed_analogue_gain_;
} else if (status_.total_exposure_value) {
- // On a mode switch, it's possible the exposure profile could change,
- // or a fixed exposure/gain might be set so we divide up the exposure/
- // gain again, but we don't change any target values.
+ // On a mode switch, various things could happen:
+ // - the exposure profile might change
+ // - a fixed exposure or gain might be set
+ // - the new mode's sensitivity might be different
+ // We cope with the last of these by scaling the target values. After
+ // that we just need to re-divide the exposure/gain according to the
+ // current exposure profile, which takes care of everything else.
+
+ double ratio = last_sensitivity_ / camera_mode.sensitivity;
+ target_.total_exposure_no_dg *= ratio;
+ target_.total_exposure *= ratio;
+ filtered_.total_exposure_no_dg *= ratio;
+ filtered_.total_exposure *= ratio;
+
divideUpExposure();
} else {
// We come through here on startup, when at least one of the shutter
@@ -308,6 +322,9 @@ void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
}
writeAndFinish(metadata, false);
+
+ // We must remember the sensitivity of this mode for the next SwitchMode.
+ last_sensitivity_ = camera_mode.sensitivity;
}
void Agc::Prepare(Metadata *image_metadata)