[libcamera-devel] [PATCH v2 05/10] ipa: ipu3: Introduce a modular contrast algorithm
Kieran Bingham
kieran.bingham at ideasonboard.com
Fri Aug 13 11:31:17 CEST 2021
On 12/08/2021 17:52, Jean-Michel Hautbois wrote:
> Introduce a new algorithm to manage the contrast handling of the IPU3.
>
> The initial algorithm is chosen to configure the gamma contrast curve
I don't think this is the 'initial algorithm' any more ...
> which moves the implementation out of AWB for simplicity. As it is
> initialised with a default gamma value of 1.1, there is no need to use
> the default table at init time anymore.
s/at init time/at initialisation/
>
> This demonstrates the way to use process() call when the EventStatReady
> comes in. The function calculates the LUT in the context of a frame, and
> when prepare() is called, the parameters are filled with the updated
> values.
>
> AGC needs to be modified to take the new process interface into account.
>
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> ---
> src/ipa/ipu3/algorithms/algorithm.h | 2 ++
> src/ipa/ipu3/algorithms/contrast.cpp | 51 ++++++++++++++++++++++++++++
> src/ipa/ipu3/algorithms/contrast.h | 33 ++++++++++++++++++
> src/ipa/ipu3/algorithms/meson.build | 3 +-
> src/ipa/ipu3/ipa_context.h | 8 +++++
> src/ipa/ipu3/ipu3.cpp | 12 +++++--
> src/ipa/ipu3/ipu3_agc.cpp | 9 +++--
> src/ipa/ipu3/ipu3_agc.h | 5 +--
> src/ipa/ipu3/ipu3_awb.cpp | 41 ++--------------------
> src/ipa/ipu3/ipu3_awb.h | 2 +-
> 10 files changed, 114 insertions(+), 52 deletions(-)
> create mode 100644 src/ipa/ipu3/algorithms/contrast.cpp
> create mode 100644 src/ipa/ipu3/algorithms/contrast.h
>
> diff --git a/src/ipa/ipu3/algorithms/algorithm.h b/src/ipa/ipu3/algorithms/algorithm.h
> index b571f55a..13e5f2d4 100644
> --- a/src/ipa/ipu3/algorithms/algorithm.h
> +++ b/src/ipa/ipu3/algorithms/algorithm.h
> @@ -28,6 +28,8 @@ public:
> }
>
> virtual void prepare([[maybe_unused]] IPAContext &context, [[maybe_unused]] ipu3_uapi_params ¶ms) {}
> +
> + virtual void process([[maybe_unused]] IPAContext &context, [[maybe_unused]] const ipu3_uapi_stats_3a *stats) {}
> };
>
> } /* namespace ipa::ipu3 */
> diff --git a/src/ipa/ipu3/algorithms/contrast.cpp b/src/ipa/ipu3/algorithms/contrast.cpp
> new file mode 100644
> index 00000000..bc00490f
> --- /dev/null
> +++ b/src/ipa/ipu3/algorithms/contrast.cpp
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Ideas On Board
Keep this consistent with contrast.h please.
> + *
> + * constrast.cpp - IPU3 Contrast and Gamma control
s/constrast/contrast/
> + */
> +
> +#include "contrast.h"
> +
> +#include <cmath>
> +
> +#include <libcamera/base/log.h>
> +
> +namespace libcamera {
> +
> +namespace ipa::ipu3::algorithms {
> +
> +LOG_DEFINE_CATEGORY(IPU3Contrast)
> +
> +Contrast::Contrast()
> + : gamma_(1.0)
> +{
> +}
> +
> +void Contrast::prepare([[maybe_unused]] IPAContext &context, ipu3_uapi_params ¶ms)
> +{
> + params.use.acc_gamma = 1;
> + params.acc_param.gamma.gc_ctrl.enable = 1;
The ordering is almost irrelevant to the code, but for some reason, I
think you should set the enable and use flags /after/ filling in the data.
Technically it doesn't matter, but conceptually, they should only be
enabled, after they are filled in correctly.
> +
> + for (uint32_t i = 0; i < IPU3_UAPI_GAMMA_CORR_LUT_ENTRIES; i++)
> + params.acc_param.gamma.gc_lut.lut[i] = context.frameContext.contrast.lut[i];
We have two tables of a fixed number of entries.
I wonder if a memcpy() would be more efficient than a loop, but perhaps
it doesn't make a difference ?
Would the compiler do the right thing if you said:
params.acc_param.gamma.gc_lut.lut = context.frameContext.contrast.lut;
In fact, I see that
params.acc_param.gamma.gc_lut.lut stores unsigned shorts,
while
context.frameContext.contrast.lut stores uint16_t
Maybe we should store a
struct ipu3_uapi_gamma_corr_lut
in context.frameContext.contrast instead, Yes they're all the same size
types - but we have access to the original type of the array, so why not
use it to keep them identical..
> +}
> +
> +void Contrast::process([[maybe_unused]] IPAContext &context, [[maybe_unused]] const ipu3_uapi_stats_3a *stats)
> +{
> + /* Limit the gamma effect for now */
Can this be explained any more? Why do we set this here and not
initialise to 1.1 in the initialisation list?
Perhaps a
\todo expose gamma control setting through the libcamera control API
should be added here too to make it clear that this is hardcoded, when
it should somehow be a parameter or control into the IPA or such.
> + gamma_ = 1.1;
> +
> + /* Plot the gamma curve into the look up table */
> + for (uint32_t i = 0; i < IPU3_UAPI_GAMMA_CORR_LUT_ENTRIES; i++) {
> + double j = i / 255.0;
> + double gamma = std::pow(j, 1.0 / gamma_);
> +
> + /* The maximum value 255 is represented on 13 bits in the IPU3 */
> + context.frameContext.contrast.lut[i] = gamma * 8191;
8191 still looks like a magic number, even with the comment.
I wonder if we should define this somewhere, perhaps as
/* The maximum value 255 is represented on 13 bits in the IPU3 */
#define LUT_INTEGER_SCALE(g) (g * ((1 << 13) - 1))
context.frameContext.contrast.lut[i] = LUT_INTEGER_SCALE(gamma);
LUT_INTEGER_SCALE may be a completely inappropriate name ... I'm guessing.
Also - even having said that - this patch is moving existing code - so
this shouldn't be changed here - but it might be a distinct patch of
it's own to come later.
> + }
> +}
> +
> +} /* namespace ipa::ipu3::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/ipu3/algorithms/contrast.h b/src/ipa/ipu3/algorithms/contrast.h
> new file mode 100644
> index 00000000..50cb626f
> --- /dev/null
> +++ b/src/ipa/ipu3/algorithms/contrast.h
> @@ -0,0 +1,33 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Google
> + *
> + * constrast.h - IPU3 Contrast and Gamma control
> + */
> +#ifndef __LIBCAMERA_IPU3_ALGORITHMS_CONTRAST_H__
> +#define __LIBCAMERA_IPU3_ALGORITHMS_CONTRAST_H__
> +
> +#include "algorithm.h"
> +
> +namespace libcamera {
> +
> +namespace ipa::ipu3::algorithms {
> +
> +class Contrast : public Algorithm
> +{
> +public:
> + Contrast();
> + ~Contrast() = default;
> +
> + void prepare(IPAContext &context, ipu3_uapi_params ¶ms) override;
> + void process(IPAContext &context, const ipu3_uapi_stats_3a *stats) override;
> +
> +private:
> + double gamma_;
> +};
> +
> +} /* namespace ipa::ipu3::algorithms */
> +
> +} /* namespace libcamera */
> +
> +#endif /* __LIBCAMERA_IPU3_ALGORITHMS_CONTRAST_H__ */
> diff --git a/src/ipa/ipu3/algorithms/meson.build b/src/ipa/ipu3/algorithms/meson.build
> index 3fb3ce56..69a59096 100644
> --- a/src/ipa/ipu3/algorithms/meson.build
> +++ b/src/ipa/ipu3/algorithms/meson.build
> @@ -1,5 +1,6 @@
> # SPDX-License-Identifier: CC0-1.0
>
> ipu3_ipa_algorithms = files([
> - 'grid.cpp',
Please fix this alignment in the patch that adds it.
> + 'contrast.cpp',
> + 'grid.cpp',
> ])
> diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
> index 90b2f2c2..e995c663 100644
> --- a/src/ipa/ipu3/ipa_context.h
> +++ b/src/ipa/ipu3/ipa_context.h
> @@ -33,6 +33,14 @@ struct IPAConfiguration {
> * lifetime, though for now a single instance is used.
> */
> struct IPAFrameContext {
> + struct Agc {
> + uint32_t exposure;
> + double gain;
> + } agc;
> +
> + struct Contrast {
> + uint16_t lut[IPU3_UAPI_GAMMA_CORR_LUT_ENTRIES];
As highilghted earlier, I think this should be:
struct ipu3_uapi_gamma_corr_lut lut
> + } contrast;
> };
>
> /* Global context of the IPA */
> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
> index 394a7a45..e09adfc3 100644
> --- a/src/ipa/ipu3/ipu3.cpp
> +++ b/src/ipa/ipu3/ipu3.cpp
> @@ -30,6 +30,7 @@
> #include "libcamera/internal/mapped_framebuffer.h"
>
> #include "algorithms/algorithm.h"
> +#include "algorithms/contrast.h"
> #include "algorithms/grid.h"
> #include "ipu3_agc.h"
> #include "ipu3_awb.h"
> @@ -167,6 +168,7 @@ int IPAIPU3::init(const IPASettings &settings,
> *ipaControls = ControlInfoMap(std::move(controls), controls::controls);
> /* Construct our Algorithms */
> algorithms_.emplace_back(new algorithms::Grid());
> + algorithms_.emplace_back(new algorithms::Contrast());
>
> return 0;
> }
> @@ -309,7 +311,7 @@ void IPAIPU3::fillParams(unsigned int frame, ipu3_uapi_params *params)
> algo->prepare(context_, params_);
>
> if (agcAlgo_->updateControls())
> - awbAlgo_->updateWbParameters(params_, agcAlgo_->gamma());
> + awbAlgo_->updateWbParameters(params_);
>
> *params = params_;
>
> @@ -324,9 +326,15 @@ void IPAIPU3::parseStatistics(unsigned int frame,
> [[maybe_unused]] const ipu3_uapi_stats_3a *stats)
> {
> ControlList ctrls(controls::controls);
New line here to separate local variable declarations from code segments.
> + for (auto const &algo : algorithms_)
> + algo->process(context_, stats);
>
> double gain = camHelper_->gain(gain_);
> - agcAlgo_->process(stats, exposure_, gain);
> + context_.frameContext.agc.exposure = exposure_;
> + context_.frameContext.agc.gain = gain;
the IPU3 layer sould not be filling in agc specific structures. That's a
layering violation to me.
The algorithms (in this instance, the agc?) own those structures, so
they should be manipulating them.
It's also showing where the algorithms need to know historical data.
In this instance, presumably they need to know what gain or expsosure
was set at the time that this buffer ran.
This shows where we will need to keep historical versions of the
FrameContext, and perhaps track them along with the frame counter.
For now, while we get things moving to be more modular, I think we could
keep this as it is - but it should be commented with a todo
> + agcAlgo_->process(context_, stats);
> + exposure_ = context_.frameContext.agc.exposure;
> + gain = context_.frameContext.agc.gain;
> gain_ = camHelper_->gainCode(gain);
>
> awbAlgo_->calculateWBGains(stats);
> diff --git a/src/ipa/ipu3/ipu3_agc.cpp b/src/ipa/ipu3/ipu3_agc.cpp
> index 408eb849..c6782ff4 100644
> --- a/src/ipa/ipu3/ipu3_agc.cpp
> +++ b/src/ipa/ipu3/ipu3_agc.cpp
> @@ -52,7 +52,7 @@ static constexpr uint8_t kCellSize = 8;
>
> IPU3Agc::IPU3Agc()
> : frameCount_(0), lastFrame_(0), converged_(false),
> - updateControls_(false), iqMean_(0.0), gamma_(1.0),
> + updateControls_(false), iqMean_(0.0),
> lineDuration_(0s), maxExposureTime_(0s),
> prevExposure_(0s), prevExposureNoDg_(0s),
> currentExposure_(0s), currentExposureNoDg_(0s)
> @@ -104,9 +104,6 @@ void IPU3Agc::processBrightness(const ipu3_uapi_stats_3a *stats)
> }
> }
>
> - /* Limit the gamma effect for now */
> - gamma_ = 1.1;
> -
> /* Estimate the quantile mean of the top 2% of the histogram */
> iqMean_ = Histogram(Span<uint32_t>(hist)).interQuantileMean(0.98, 1.0);
> }
> @@ -193,8 +190,10 @@ void IPU3Agc::lockExposureGain(uint32_t &exposure, double &gain)
> lastFrame_ = frameCount_;
> }
>
> -void IPU3Agc::process(const ipu3_uapi_stats_3a *stats, uint32_t &exposure, double &gain)
> +void IPU3Agc::process(IPAContext &context, const ipu3_uapi_stats_3a *stats)
> {
> + uint32_t &exposure = context.frameContext.agc.exposure;
> + double &gain = context.frameContext.agc.gain;
> processBrightness(stats);
> lockExposureGain(exposure, gain);
> frameCount_++;
> diff --git a/src/ipa/ipu3/ipu3_agc.h b/src/ipa/ipu3/ipu3_agc.h
> index f00b98d6..8b32e52f 100644
> --- a/src/ipa/ipu3/ipu3_agc.h
> +++ b/src/ipa/ipu3/ipu3_agc.h
> @@ -30,11 +30,9 @@ public:
> ~IPU3Agc() = default;
>
> void initialise(struct ipu3_uapi_grid_config &bdsGrid, const IPACameraSensorInfo &sensorInfo);
> - void process(const ipu3_uapi_stats_3a *stats, uint32_t &exposure, double &gain);
> + void process(IPAContext &context, const ipu3_uapi_stats_3a *stats) override;
> bool converged() { return converged_; }
> bool updateControls() { return updateControls_; }
> - /* \todo Use a metadata exchange between IPAs */
> - double gamma() { return gamma_; }
>
> private:
> void processBrightness(const ipu3_uapi_stats_3a *stats);
> @@ -50,7 +48,6 @@ private:
> bool updateControls_;
>
> double iqMean_;
> - double gamma_;
>
> Duration lineDuration_;
> Duration maxExposureTime_;
> diff --git a/src/ipa/ipu3/ipu3_awb.cpp b/src/ipa/ipu3/ipu3_awb.cpp
> index 911760b3..0f3bcdc9 100644
> --- a/src/ipa/ipu3/ipu3_awb.cpp
> +++ b/src/ipa/ipu3/ipu3_awb.cpp
> @@ -114,31 +114,6 @@ static const struct ipu3_uapi_ccm_mat_config imguCssCcmDefault = {
> 0, 0, 8191, 0
> };
>
> -/* Default settings for Gamma correction */
> -const struct ipu3_uapi_gamma_corr_lut imguCssGammaLut = { {
> - 63, 79, 95, 111, 127, 143, 159, 175, 191, 207, 223, 239, 255, 271, 287,
> - 303, 319, 335, 351, 367, 383, 399, 415, 431, 447, 463, 479, 495, 511,
> - 527, 543, 559, 575, 591, 607, 623, 639, 655, 671, 687, 703, 719, 735,
> - 751, 767, 783, 799, 815, 831, 847, 863, 879, 895, 911, 927, 943, 959,
> - 975, 991, 1007, 1023, 1039, 1055, 1071, 1087, 1103, 1119, 1135, 1151,
> - 1167, 1183, 1199, 1215, 1231, 1247, 1263, 1279, 1295, 1311, 1327, 1343,
> - 1359, 1375, 1391, 1407, 1423, 1439, 1455, 1471, 1487, 1503, 1519, 1535,
> - 1551, 1567, 1583, 1599, 1615, 1631, 1647, 1663, 1679, 1695, 1711, 1727,
> - 1743, 1759, 1775, 1791, 1807, 1823, 1839, 1855, 1871, 1887, 1903, 1919,
> - 1935, 1951, 1967, 1983, 1999, 2015, 2031, 2047, 2063, 2079, 2095, 2111,
> - 2143, 2175, 2207, 2239, 2271, 2303, 2335, 2367, 2399, 2431, 2463, 2495,
> - 2527, 2559, 2591, 2623, 2655, 2687, 2719, 2751, 2783, 2815, 2847, 2879,
> - 2911, 2943, 2975, 3007, 3039, 3071, 3103, 3135, 3167, 3199, 3231, 3263,
> - 3295, 3327, 3359, 3391, 3423, 3455, 3487, 3519, 3551, 3583, 3615, 3647,
> - 3679, 3711, 3743, 3775, 3807, 3839, 3871, 3903, 3935, 3967, 3999, 4031,
> - 4063, 4095, 4127, 4159, 4223, 4287, 4351, 4415, 4479, 4543, 4607, 4671,
> - 4735, 4799, 4863, 4927, 4991, 5055, 5119, 5183, 5247, 5311, 5375, 5439,
> - 5503, 5567, 5631, 5695, 5759, 5823, 5887, 5951, 6015, 6079, 6143, 6207,
> - 6271, 6335, 6399, 6463, 6527, 6591, 6655, 6719, 6783, 6847, 6911, 6975,
> - 7039, 7103, 7167, 7231, 7295, 7359, 7423, 7487, 7551, 7615, 7679, 7743,
> - 7807, 7871, 7935, 7999, 8063, 8127, 8191
> -} };
> -
> IPU3Awb::IPU3Awb()
> : Algorithm()
> {
> @@ -179,10 +154,6 @@ void IPU3Awb::initialise(ipu3_uapi_params ¶ms, const Size &bdsOutputSize, st
> params.use.acc_ccm = 1;
> params.acc_param.ccm = imguCssCcmDefault;
>
> - params.use.acc_gamma = 1;
> - params.acc_param.gamma.gc_lut = imguCssGammaLut;
> - params.acc_param.gamma.gc_ctrl.enable = 1;
> -
> zones_.reserve(kAwbStatsSizeX * kAwbStatsSizeY);
> }
>
> @@ -332,7 +303,7 @@ void IPU3Awb::calculateWBGains(const ipu3_uapi_stats_3a *stats)
> }
> }
>
> -void IPU3Awb::updateWbParameters(ipu3_uapi_params ¶ms, double agcGamma)
> +void IPU3Awb::updateWbParameters(ipu3_uapi_params ¶ms)
> {
> /*
> * Green gains should not be touched and considered 1.
> @@ -344,18 +315,10 @@ void IPU3Awb::updateWbParameters(ipu3_uapi_params ¶ms, double agcGamma)
> params.acc_param.bnr.wb_gains.b = 4096 * asyncResults_.blueGain;
> params.acc_param.bnr.wb_gains.gb = 16;
>
> - LOG(IPU3Awb, Debug) << "Color temperature estimated: " << asyncResults_.temperatureK
> - << " and gamma calculated: " << agcGamma;
> + LOG(IPU3Awb, Debug) << "Color temperature estimated: " << asyncResults_.temperatureK;
>
> /* The CCM matrix may change when color temperature will be used */
> params.acc_param.ccm = imguCssCcmDefault;
> -
> - for (uint32_t i = 0; i < 256; i++) {
> - double j = i / 255.0;
> - double gamma = std::pow(j, 1.0 / agcGamma);
> - /* The maximum value 255 is represented on 13 bits in the IPU3 */
> - params.acc_param.gamma.gc_lut.lut[i] = gamma * 8191;
> - }
> }
>
> } /* namespace ipa::ipu3 */
> diff --git a/src/ipa/ipu3/ipu3_awb.h b/src/ipa/ipu3/ipu3_awb.h
> index ea2d4320..eeb2920b 100644
> --- a/src/ipa/ipu3/ipu3_awb.h
> +++ b/src/ipa/ipu3/ipu3_awb.h
> @@ -31,7 +31,7 @@ public:
>
> void initialise(ipu3_uapi_params ¶ms, const Size &bdsOutputSize, struct ipu3_uapi_grid_config &bdsGrid);
> void calculateWBGains(const ipu3_uapi_stats_3a *stats);
> - void updateWbParameters(ipu3_uapi_params ¶ms, double agcGamma);
> + void updateWbParameters(ipu3_uapi_params ¶ms);
>
> struct Ipu3AwbCell {
> unsigned char greenRedAvg;
>
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