[libcamera-devel] [PATCH v3 3/4] libcamera: ipa: raspberrypi: ALSC: Resample luminance table
Naushir Patuck
naush at raspberrypi.com
Wed Aug 5 08:51:14 CEST 2020
Hi Laurent and David
On Wed, 5 Aug 2020 at 00:47, Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Naush,
>
> Thanks for the reviews. Do you plan to review 4/4 too ?
My sent mail folder shows I had replied with the Reviewed-by tag for
patch 4/4. Perhaps something got lost in the way. I will resend.
Regards,
Naush
>
> On Tue, Aug 04, 2020 at 09:49:17AM +0100, Naushir Patuck wrote:
> > Hi David,
> >
> > Thank you for the patch, LGTM.
> >
> > On Sat, 1 Aug 2020 at 09:02, David Plowman wrote:
> > >
> > > This fixes a bug where the luminance correction table was not being
> > > resampled according to the camera mode, in the same way as the colour
> > > tables. This could be noticeable if any camera modes crop
> > > aggressively.
> > >
> > > This resampling can be done "up front" in the SwitchMode, as we have
> > > only a single fixed luminance table. In order to protect the
> > > recalculation of the table from the asynchronous thread (which reads
> > > it) I've elected to wait for that thread to go idle (though I doubt it
> > > would have mattered much). As a by-product of stopping the thread, it
> > > no longer needs its own copy of the camera mode (async_camera_mode_).
> > >
> > > Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> > > Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> >
> > Reviewed-by: Naushir Patuck <naush at raspberrypi.com>
> >
> > > ---
> > > src/ipa/raspberrypi/controller/rpi/alsc.cpp | 39 ++++++++++++++-------
> > > src/ipa/raspberrypi/controller/rpi/alsc.hpp | 3 +-
> > > 2 files changed, 28 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.cpp b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> > > index 12359dc..4df9934 100644
> > > --- a/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> > > +++ b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
> > > @@ -173,19 +173,34 @@ void Alsc::Initialise()
> > > lambda_r_[i] = lambda_b_[i] = 1.0;
> > > }
> > >
> > > +void Alsc::waitForAysncThread()
> > > +{
> > > + if (async_started_) {
> > > + async_started_ = false;
> > > + std::unique_lock<std::mutex> lock(mutex_);
> > > + sync_signal_.wait(lock, [&] {
> > > + return async_finished_;
> > > + });
> > > + async_finished_ = false;
> > > + }
> > > +}
> > > +
> > > void Alsc::SwitchMode(CameraMode const &camera_mode, Metadata *metadata)
> > > {
> > > (void)metadata;
> > >
> > > + // Ensure the other thread isn't running while we do this.
> > > + waitForAysncThread();
> > > +
> > > // There's a bit of a question what we should do if the "crop" of the
> > > - // camera mode has changed. Any calculation currently in flight would
> > > - // not be useful to the new mode, so arguably we should abort it, and
> > > - // generate a new table (like the "first_time" code already here). When
> > > - // the crop doesn't change, we can presumably just leave things
> > > - // alone. For now, I think we'll just wait and see. When the crop does
> > > - // change, any effects should be transient, and if they're not transient
> > > - // enough, we'll revisit the question then.
> > > + // camera mode has changed. Should we effectively reset the algorithm
> > > + // and start over?
> > > camera_mode_ = camera_mode;
> > > +
> > > + // We must resample the luminance table like we do the others, but it's
> > > + // fixed so we can simply do it up front here.
> > > + resample_cal_table(config_.luminance_lut, camera_mode_, luminance_table_);
> > > +
> > > if (first_time_) {
> > > // On the first time, arrange for something sensible in the
> > > // initial tables. Construct the tables for some default colour
> > > @@ -201,7 +216,7 @@ void Alsc::SwitchMode(CameraMode const &camera_mode, Metadata *metadata)
> > > compensate_lambdas_for_cal(cal_table_b, lambda_b_,
> > > async_lambda_b_);
> > > add_luminance_to_tables(sync_results_, async_lambda_r_, 1.0,
> > > - async_lambda_b_, config_.luminance_lut,
> > > + async_lambda_b_, luminance_table_,
> > > config_.luminance_strength);
> > > memcpy(prev_sync_results_, sync_results_,
> > > sizeof(prev_sync_results_));
> > > @@ -266,8 +281,6 @@ void Alsc::restartAsync(StatisticsPtr &stats, Metadata *image_metadata)
> > > }
> > > copy_stats(statistics_, stats, alsc_status);
> > > frame_phase_ = 0;
> > > - // copy the camera mode so it won't change during the calculations
> > > - async_camera_mode_ = camera_mode_;
> > > async_started_ = true;
> > > {
> > > std::lock_guard<std::mutex> lock(mutex_);
> > > @@ -672,9 +685,9 @@ void Alsc::doAlsc()
> > > // Fetch the new calibrations (if any) for this CT. Resample them in
> > > // case the camera mode is not full-frame.
> > > get_cal_table(ct_, config_.calibrations_Cr, cal_table_tmp);
> > > - resample_cal_table(cal_table_tmp, async_camera_mode_, cal_table_r);
> > > + resample_cal_table(cal_table_tmp, camera_mode_, cal_table_r);
> > > get_cal_table(ct_, config_.calibrations_Cb, cal_table_tmp);
> > > - resample_cal_table(cal_table_tmp, async_camera_mode_, cal_table_b);
> > > + resample_cal_table(cal_table_tmp, camera_mode_, cal_table_b);
> > > // You could print out the cal tables for this image here, if you're
> > > // tuning the algorithm...
> > > (void)print_cal_table;
> > > @@ -697,7 +710,7 @@ void Alsc::doAlsc()
> > > compensate_lambdas_for_cal(cal_table_b, lambda_b_, async_lambda_b_);
> > > // Fold in the luminance table at the appropriate strength.
> > > add_luminance_to_tables(async_results_, async_lambda_r_, 1.0,
> > > - async_lambda_b_, config_.luminance_lut,
> > > + async_lambda_b_, luminance_table_,
> > > config_.luminance_strength);
> > > }
> > >
> > > diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.hpp b/src/ipa/raspberrypi/controller/rpi/alsc.hpp
> > > index e895913..95572af 100644
> > > --- a/src/ipa/raspberrypi/controller/rpi/alsc.hpp
> > > +++ b/src/ipa/raspberrypi/controller/rpi/alsc.hpp
> > > @@ -60,10 +60,10 @@ private:
> > > AlscConfig config_;
> > > bool first_time_;
> > > CameraMode camera_mode_;
> > > + double luminance_table_[ALSC_CELLS_X * ALSC_CELLS_Y];
> > > std::thread async_thread_;
> > > void asyncFunc(); // asynchronous thread function
> > > std::mutex mutex_;
> > > - CameraMode async_camera_mode_;
> > > // condvar for async thread to wait on
> > > std::condition_variable async_signal_;
> > > // condvar for synchronous thread to wait on
> > > @@ -86,6 +86,7 @@ private:
> > > int frame_count2_;
> > > double sync_results_[3][ALSC_CELLS_Y][ALSC_CELLS_X];
> > > double prev_sync_results_[3][ALSC_CELLS_Y][ALSC_CELLS_X];
> > > + void waitForAysncThread();
> > > // The following are for the asynchronous thread to use, though the main
> > > // thread can set/reset them if the async thread is known to be idle:
> > > void restartAsync(StatisticsPtr &stats, Metadata *image_metadata);
>
> --
> Regards,
>
> Laurent Pinchart
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