[libcamera-devel] [RFC v5] ipa: ipu3: af: Auto focus for dw9719 Surface Go2 VCM
Jean-Michel Hautbois
jeanmichel.hautbois at ideasonboard.com
Fri Jan 21 10:26:38 CET 2022
Hi Kate,
Thanks for the patch !
On 20/01/2022 12:41, Kate Hsuan wrote:
> Since VCM for surface Go 2 (dw9719) had been successfully
> driven, this Af module can be used to control the VCM and
> determine the focus value based on the IPU3 AF state.
>
> The variance of each focus step is determined and a greedy
> approah is used to find the maximum variance of the AF
> state and a appropriate focus value.
s/approah/approach
>
> The grid configuration is implemented as a context. Also,
> the grid parameter- AF_MIN_BLOCK_WIDTH is set to 4 (default
> is 3) since if the default value is used, x_start
> (x_start > 640) will be at an incorrect location of the
> image (rightmost of the sensor).
We should investigate this, as it should not be a blocker ?
>
> Signed-off-by: Kate Hsuan <hpa at redhat.com>
> ---
> src/ipa/ipu3/algorithms/af.cpp | 367 ++++++++++++++++++++++++++++
> src/ipa/ipu3/algorithms/af.h | 79 ++++++
> src/ipa/ipu3/algorithms/meson.build | 3 +-
> src/ipa/ipu3/ipa_context.cpp | 24 ++
> src/ipa/ipu3/ipa_context.h | 10 +
> src/ipa/ipu3/ipu3.cpp | 32 +++
> 6 files changed, 514 insertions(+), 1 deletion(-)
> create mode 100644 src/ipa/ipu3/algorithms/af.cpp
> create mode 100644 src/ipa/ipu3/algorithms/af.h
>
> diff --git a/src/ipa/ipu3/algorithms/af.cpp b/src/ipa/ipu3/algorithms/af.cpp
> new file mode 100644
> index 00000000..26c98868
> --- /dev/null
> +++ b/src/ipa/ipu3/algorithms/af.cpp
> @@ -0,0 +1,367 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Red Hat
> + *
> + * af.cpp - IPU3 auto focus control
> + */
> +
> +#include "af.h"
> +
> +#include <algorithm>
> +#include <chrono>
> +#include <cmath>
> +#include <fcntl.h>
> +#include <numeric>
> +#include <sys/ioctl.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +
> +#include <linux/videodev2.h>
> +
> +#include <libcamera/base/log.h>
> +
> +#include <libcamera/ipa/core_ipa_interface.h>
> +
> +#include "libipa/histogram.h"
> +
> +/**
> + * \file af.h
> + */
> +
> +/**
> + * \def AF_MIN_GRID_WIDTH
> + * \brief the minimum width of AF grid.
> + * The minimum grid horizontal dimensions, in number of grid blocks(cells).
> +*/
This is true for this one and all the defines, please replace those by
static constexpr instead ?
> +
> +/**
> + * \def AF_MIN_GRID_HEIGHT
> + * \brief the minimum height of AF grid.
> + * The minimum grid horizontal dimensions, in number of grid blocks(cells).
> +*/
> +
> +/**
> + * \def AF_MIN_BLOCK_WIDTH
> + * \brief the minimum block size of the width.
> + */
> +
> +/**
> + * \def AF_MAX_GRID_HEIGHT
> + * \brief the minimum height of AF grid.
> + * The minimum grid horizontal dimensions, in number of grid blocks(cells).
> +*/
> +
> +/**
> + * \def AF_MAX_BLOCK_WIDTH
> + * \brief the minimum block size of the width.
> + */
> +
> +/**
> + * \def AF_MAX_BLOCK_WIDTH
> + * \brief the maximum block size of the width.
> + */
> +
> +/**
> + * \def AF_MIN_BLOCK_HEIGHT
> + * \brief the minimum block size of the height.
> + */
> +
> +/**
> + * \def AF_MAX_BLOCK_HEIGHT
> + * \brief the maximum block size of the height.
> + */
> +
> +/**
> + * \def AF_DEFAULT_HEIGHT_PER_SLICE
> + * \brief The default number of blocks in vertical axis per slice.
> + */
> +
> +namespace libcamera {
> +
> +using namespace std::literals::chrono_literals;
> +
> +namespace ipa::ipu3::algorithms {
> +
> +/**
> + * \class Af
> + * \brief A IPU3 auto-focus accelerator based auto focus algorthim
'An auto-focus algorithm based on IPU3 statistics' maybe ?
This proposal should be taken with a grain of salt, as I am not a native
speaker ;-).
> + *
> + * This algorithm is used to determine the position of the lens and get a
> + * focused image. The IPU3 AF accelerator computes the statistics, composed
s/accelerator/processing block/
> + * by high pass and low pass filtered value and stores in a AF buffer.
> + * Typically, for a focused image, it has relative high contrast than a
> + * blurred image, i.e. an out of focus image. Therefore, if an image with the
> + * highest contrast can be found from the AF scan, the lens' position is the
> + * best step of the focus.
> + *
> + */
> +
> +LOG_DEFINE_CATEGORY(IPU3Af)
> +
> +/**
> + * Maximum focus value of the VCM control
> + * \todo should be obtained from the VCM driver
> + */
> +static constexpr uint32_t MaxFocusSteps_ = 1023;
Remove the trailing underscore (same below):
s/MaxFocusSteps_/maxFocusSteps/
> +
> +/* minimum focus step for searching appropriate focus */
> +static constexpr uint32_t coarseSearchStep_ = 10;
> +static constexpr uint32_t fineSearchStep_ = 1;
Correct me if I am wrong:
- the coarse step is used to determine a first approximation of the
focused image
- The fine step is then used to find the optimal lens position
The VCM used on SGo2 has 1024 steps, so, you may search for ~100 frames
(ie ~3 seconds at 30fps) before going into the fine search step ?
> +
> +/* max ratio of variance change, 0.0 < MaxChange_ < 1.0 */
> +static constexpr double MaxChange_ = 0.2;
> +
> +/* the numbers of frame to be ignored, before performing focus scan. */
> +static constexpr uint32_t ignoreFrame_ = 10;
> +
> +/* fine scan range 0 < findRange_ < 1 */
> +static constexpr double findRange_ = 0.05;
> +
> +/* settings for Auto Focus from the kernel */
Those filters are not the ones defined in the kernel ;-).
> +static struct ipu3_uapi_af_filter_config afFilterConfigDefault = {
> + { 0, 1, 3, 7 },
> + { 11, 13, 1, 2 },
> + { 8, 19, 34, 242 },
> + 0x7fdffbfe,
> + { 0, 1, 6, 6 },
> + { 13, 25, 3, 0 },
> + { 25, 3, 177, 254 },
> + 0x4e53ca72,
> + .y_calc = { 8, 8, 8, 8 },
> + .nf = { 0, 9, 0, 9, 0 },
> +};
Use the fields names for all the structure:
static struct ipu3_uapi_af_filter_config afFilterConfigDefault = {
.y1_coeff_0 = { 0, 1, 3, 7 },
.y1_coeff_1 = { 11, 13, 1, 2 },
etc.
};
> +
> +Af::Af()
> + : focus_(0), goodFocus_(0), currentVariance_(0.0), previousVariance_(0.0),
> + coarseComplete_(false), fineComplete_(false)
> +{
> + maxStep_ = MaxFocusSteps_;
> +}
> +
> +Af::~Af()
> +{
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::prepare
> + */
> +void Af::prepare(IPAContext &context, ipu3_uapi_params *params)
> +{
> + const struct ipu3_uapi_grid_config &grid = context.configuration.af.afGrid;
> + params->acc_param.af.grid_cfg = grid;
> + params->acc_param.af.filter_config = afFilterConfigDefault;
> +
> + /* enable AF acc */
s/acc/processing block/
> + params->use.acc_af = 1;
> +}
> +
> +/**
> + * \brief Configure the Af given a configInfo
> + * \param[in] context The shared IPA context
> + * \param[in] configInfo The IPA configuration data
> + *
> + * \return 0
> + */
> +int Af::configure(IPAContext &context,
> + [[maybe_unused]] const IPAConfigInfo &configInfo)
Are you using the utils/hooks/ in your git repo ?
If so, I think you should have a misaligned warning here ?
> +{
> + /* determined focus value i.e. current focus value */
> + context.frameContext.af.focus = 0;
> + /* maximum variance of the AF statistics */
> + context.frameContext.af.maxVariance = 0;
> + /* the stable AF value flag. if it is true, the AF should be in a stable state. */
> + context.frameContext.af.stable = false;
> + /* AF buffer length */
> + afRawBufferLen_ = context.configuration.af.afGrid.width *
> + context.configuration.af.afGrid.height;
AFAIK, this is only used in the process() function, maybe could it be a
local variable ?
> +
> + return 0;
> +}
> +
> +/**
> + * \brief AF coarse scan
> + * \param[in] context The shared IPA context
> + *
> + */
> +void Af::afCoarseScan(IPAContext &context)
> +{
> + if (coarseComplete_ == true)
> + return;
> +
> + if (afScan(context, coarseSearchStep_)) {
> + coarseComplete_ = true;
> + context.frameContext.af.maxVariance = 0;
> + focus_ = context.frameContext.af.focus - (context.frameContext.af.focus * findRange_);
> + context.frameContext.af.focus = focus_;
> + previousVariance_ = 0;
> + maxStep_ = std::clamp(static_cast<uint32_t>(focus_ + (focus_ * findRange_)), 0U, MaxFocusSteps_);
> + }
> +}
> +
> +/**
> + * \brief AF fine scan
> + *
> + * Finetune the lens position with moving 1 step for each variance computation.
> + *
> + * \param[in] context The shared IPA context
> + *
> + */
> +void Af::afFineScan(IPAContext &context)
> +{
> + if (coarseComplete_ != true)
> + return;
> +
> + if (afScan(context, fineSearchStep_)) {
> + context.frameContext.af.stable = true;
> + fineComplete_ = true;
> + }
> +}
> +
> +/**
> + * \brief AF reset
> + *
> + * Reset all the parameter to start over the AF process.
> + *
> + * \param[in] context The shared IPA context
> + *
> + */
> +void Af::afReset(IPAContext &context)
> +{
> + context.frameContext.af.maxVariance = 0;
> + context.frameContext.af.focus = 0;
> + focus_ = 0;
> + context.frameContext.af.stable = false;
> + ignoreCounter_ = ignoreFrame_;
> + previousVariance_ = 0.0;
> + coarseComplete_ = false;
> + fineComplete_ = false;
> + maxStep_ = MaxFocusSteps_;
> +}
> +
> +/**
> + * \brief AF scan
> + * \param[in] context The shared IPA context
> + *
> + * \return True, if it finds a AF value.
> + */
> +bool Af::afScan(IPAContext &context, int min_step)
> +{
> + /* find the maximum variance during the AF scan using a greedy strategy */
> + if (currentVariance_ > context.frameContext.af.maxVariance) {
> + context.frameContext.af.maxVariance = currentVariance_;
> + goodFocus_ = focus_;
> + }
> +
> + if (focus_ > maxStep_) {
> + /* if reach the max step, move lens to the position and set "focus stable". */
> + context.frameContext.af.focus = goodFocus_;
> + return true;
> + } else {
> + /* check negative gradient */
> + if ((currentVariance_ - context.frameContext.af.maxVariance) > -(context.frameContext.af.maxVariance * 0.15)) {
> + focus_ += min_step;
> + context.frameContext.af.focus = focus_;
> + } else {
> + context.frameContext.af.focus = goodFocus_;
> + previousVariance_ = currentVariance_;
> + return true;
> + }
> + }
> + LOG(IPU3Af, Debug) << "Variance previous: "
> + << previousVariance_
> + << " current: "
> + << currentVariance_
> + << " Diff: "
> + << (currentVariance_ - context.frameContext.af.maxVariance);
> + previousVariance_ = currentVariance_;
> + LOG(IPU3Af, Debug) << "Focus searching max variance is: "
> + << context.frameContext.af.maxVariance
> + << " Focus step is "
> + << goodFocus_
> + << " Current scan is "
> + << focus_;
> + return false;
> +}
> +
> +/**
> + * \brief Determine the max contrast image and lens position. y_table is the
> + * statictic data from IPU3 and is composed of low pass and high pass filtered
> + * value. High pass filtered value also represents the sharpness of the image.
> + * Based on this, if the image with highest variance of the high pass filtered
> + * value (contrast) during the AF scan, the position of the lens should be the
> + * best focus.
> + * \param[in] context The shared IPA context.
> + * \param[in] stats The statistic buffer of 3A from the IPU3.
> + */
> +void Af::process(IPAContext &context, const ipu3_uapi_stats_3a *stats)
> +{
> + uint32_t total = 0;
> + double mean;
> + uint64_t var_sum = 0;
> + y_table_item_t *y_item;
> + uint32_t z = 0;
> +
> + y_item = (y_table_item_t *)stats->af_raw_buffer.y_table;
> +
> + /**
> + * Calculate the mean and the varience AF statistics, since IPU3 only determine the AF value
> + * for a given grid.
> + * For coarse: low pass results are used.
> + * For fine: high pass results are used.
> + */
> + if (coarseComplete_) {
> + for (z = 0; z < afRawBufferLen_; z++) {
> + total = total + y_item[z].y2_avg;
> + }
> + mean = total / afRawBufferLen_;
> +
> + for (z = 0; z < afRawBufferLen_; z++) {
> + var_sum = var_sum + ((y_item[z].y2_avg - mean) * (y_item[z].y2_avg - mean));
> + }
> + } else {
> + for (z = 0; z < afRawBufferLen_; z++) {
> + total = total + y_item[z].y1_avg;
> + }
> + mean = total / afRawBufferLen_;
> +
> + for (z = 0; z < afRawBufferLen_; z++) {
> + var_sum = var_sum + ((y_item[z].y1_avg - mean) * (y_item[z].y1_avg - mean));
> + }
> + }
> +
> + /* Determine the average variance of the frame. */
> + currentVariance_ = static_cast<double>(var_sum) / static_cast<double>(afRawBufferLen_);
> + LOG(IPU3Af, Debug) << "variance: " << currentVariance_;
> +
> + if (context.frameContext.af.stable == true) {
> + const uint32_t diff_var = std::abs(currentVariance_ - context.frameContext.af.maxVariance);
> + const double var_ratio = diff_var / context.frameContext.af.maxVariance;
> + LOG(IPU3Af, Debug) << "Rate of variance change: "
> + << var_ratio
> + << " current focus step: "
> + << context.frameContext.af.focus;
> + /**
> + * If the change ratio of contrast is over Maxchange_ (out of focus),
> + * trigger AF again.
> + */
> + if (var_ratio > MaxChange_) {
> + if (ignoreCounter_ == 0) {
> + afReset(context);
> + } else
> + ignoreCounter_--;
> + } else
> + ignoreCounter_ = ignoreFrame_;
> + } else {
> + if (ignoreCounter_ != 0)
> + ignoreCounter_--;
> + else {
> + afCoarseScan(context);
> + afFineScan(context);
> + }
> + }
> +}
> +
> +} /* namespace ipa::ipu3::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/ipu3/algorithms/af.h b/src/ipa/ipu3/algorithms/af.h
> new file mode 100644
> index 00000000..5654a964
> --- /dev/null
> +++ b/src/ipa/ipu3/algorithms/af.h
> @@ -0,0 +1,79 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Red Hat
> + *
> + * af.h - IPU3 Af control
> + */
> +#ifndef __LIBCAMERA_IPU3_ALGORITHMS_AF_H__
> +#define __LIBCAMERA_IPU3_ALGORITHMS_AF_H__
> +
> +#include <linux/intel-ipu3.h>
> +
> +#include <libcamera/base/utils.h>
> +
> +#include <libcamera/geometry.h>
> +
> +#include "algorithm.h"
> +
> +/* Definitions from repo of chromium */
> +#define AF_MIN_GRID_WIDTH 16
> +#define AF_MIN_GRID_HEIGHT 16
> +#define AF_MAX_GRID_WIDTH 32
> +#define AF_MAX_GRID_HEIGHT 24
> +#define AF_MIN_BLOCK_WIDTH 4
> +#define AF_MIN_BLOCK_HEIGHT 3
> +#define AF_MAX_BLOCK_WIDTH 6
> +#define AF_MAX_BLOCK_HEIGHT 6
> +#define AF_DEFAULT_HEIGHT_PER_SLICE 2
> +
> +namespace libcamera {
> +
> +namespace ipa::ipu3::algorithms {
> +
> +class Af : public Algorithm
> +{
> + /* The format of y_table. From ipu3-ipa repo */
> + typedef struct __attribute__((packed)) y_table_item {
> + uint16_t y1_avg;
> + uint16_t y2_avg;
> + } y_table_item_t;
> +
> +public:
> + Af();
> + ~Af();
> +
> + void prepare(IPAContext &context, ipu3_uapi_params *params) override;
> + int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
> + void process(IPAContext &context, const ipu3_uapi_stats_3a *stats) override;
> +
> +private:
> + void afCoarseScan(IPAContext &context);
> + void afFineScan(IPAContext &context);
> + bool afScan(IPAContext &context, int min_step);
> + void afReset(IPAContext &context);
> +
> + /* Used for focus scan. */
> + uint32_t focus_;
> + /* Focus good */
> + uint32_t goodFocus_;
> + /* Recent AF statistic variance. */
> + double currentVariance_;
> + /* The frames to be ignore before starting measuring. */
> + uint32_t ignoreCounter_;
> + /* previous variance. it is used to determine the gradient */
> + double previousVariance_;
> + /* Max scan steps of each pass of AF scaning */
> + uint32_t maxStep_;
> + /* coarse scan stable. Complete low pass search (coarse) scan) */
> + bool coarseComplete_;
> + /* fine scan stable. Complete high pass scan (fine scan) */
> + bool fineComplete_;
> + /* Raw buffer length */
> + uint32_t afRawBufferLen_;
> +};
> +
> +} /* namespace ipa::ipu3::algorithms */
> +
> +} /* namespace libcamera */
> +
> +#endif /* __LIBCAMERA_IPU3_ALGORITHMS_AF_H__ */
> diff --git a/src/ipa/ipu3/algorithms/meson.build b/src/ipa/ipu3/algorithms/meson.build
> index 4db6ae1d..e1099169 100644
> --- a/src/ipa/ipu3/algorithms/meson.build
> +++ b/src/ipa/ipu3/algorithms/meson.build
> @@ -1,8 +1,9 @@
> # SPDX-License-Identifier: CC0-1.0
>
> ipu3_ipa_algorithms = files([
> + 'af.cpp',
> 'agc.cpp',
> 'awb.cpp',
> 'blc.cpp',
> - 'tone_mapping.cpp',
> + 'tone_mapping.cpp'
> ])
> diff --git a/src/ipa/ipu3/ipa_context.cpp b/src/ipa/ipu3/ipa_context.cpp
> index 86794ac1..ecb2b90a 100644
> --- a/src/ipa/ipu3/ipa_context.cpp
> +++ b/src/ipa/ipu3/ipa_context.cpp
> @@ -67,6 +67,30 @@ namespace libcamera::ipa::ipu3 {
> *
> * \var IPASessionConfiguration::grid.stride
> * \brief Number of cells on one line including the ImgU padding
> + *
> + */
> +
> +/**
> + * \var IPASessionConfiguration::af
> + * \brief AF grid configuration of the IPA
> + *
> + * \var IPASessionConfiguration::af.afGrid
> + *
> + */
> +
> +/**
> + * \var IPAFrameContext::af
> + * \brief Context for the Automatic Focus algorithm
> + *
> + * \struct IPAFrameContext::af
> + * \var IPAFrameContext::af.focus
> + * \brief Current position of the lens
> + *
> + * \var IPAFrameContext::af.maxVariance
> + * \brief The maximum variance of the current image.
> + *
> + * \var IPAFrameContext::af.stable
> + * \brief is the image focused?
> */
>
> /**
> diff --git a/src/ipa/ipu3/ipa_context.h b/src/ipa/ipu3/ipa_context.h
> index c6dc0814..e643d38f 100644
> --- a/src/ipa/ipu3/ipa_context.h
> +++ b/src/ipa/ipu3/ipa_context.h
> @@ -31,6 +31,10 @@ struct IPASessionConfiguration {
> double minAnalogueGain;
> double maxAnalogueGain;
> } agc;
> +
> + struct {
> + ipu3_uapi_grid_config afGrid;
> + } af;
> };
>
> struct IPAFrameContext {
> @@ -49,6 +53,12 @@ struct IPAFrameContext {
> double temperatureK;
> } awb;
>
> + struct {
> + uint32_t focus;
> + double maxVariance;
> + bool stable;
> + } af;
> +
> struct {
> uint32_t exposure;
> double gain;
> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
> index 3d307708..b5149bcd 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/af.h"
> #include "algorithms/agc.h"
> #include "algorithms/algorithm.h"
> #include "algorithms/awb.h"
> @@ -157,6 +158,7 @@ private:
>
> void setControls(unsigned int frame);
> void calculateBdsGrid(const Size &bdsOutputSize);
> + void initAfGrid(const Size &bdsOutputSize);
>
> std::map<unsigned int, MappedFrameBuffer> buffers_;
>
> @@ -294,6 +296,7 @@ int IPAIPU3::init(const IPASettings &settings,
> }
>
> /* Construct our Algorithms */
> + algorithms_.push_back(std::make_unique<algorithms::Af>());
> algorithms_.push_back(std::make_unique<algorithms::Agc>());
> algorithms_.push_back(std::make_unique<algorithms::Awb>());
> algorithms_.push_back(std::make_unique<algorithms::BlackLevelCorrection>());
> @@ -395,6 +398,33 @@ void IPAIPU3::calculateBdsGrid(const Size &bdsOutputSize)
> << (int)bdsGrid.height << " << " << (int)bdsGrid.block_height_log2 << ")";
> }
>
> +/**
> + * \brief Configure the IPU3 AF grid
> + *
> + * This function gives the default values for the AF grid configuration.
> + * All the parameters are set to the minimum acceptable values.
> + *
> + * \param bdsOutputSize The bsd output size
> + */
> +void IPAIPU3::initAfGrid(const Size &bdsOutputSize)
> +{
> + struct ipu3_uapi_grid_config &grid = context_.configuration.af.afGrid;
> + grid.width = AF_MIN_GRID_WIDTH;
> + grid.height = AF_MIN_GRID_HEIGHT;
> + grid.block_width_log2 = AF_MIN_BLOCK_WIDTH;
> + grid.block_height_log2 = AF_MIN_BLOCK_HEIGHT;
> + grid.height_per_slice = AF_DEFAULT_HEIGHT_PER_SLICE;
> + /* x_start and y start are default to BDS center */
> + grid.x_start = (bdsOutputSize.width / 2) -
> + (((grid.width << grid.block_width_log2) / 2));
> + grid.y_start = (bdsOutputSize.height / 2) -
> + (((grid.height << grid.block_height_log2) / 2));
> + /* make sure x_start is multiplied by 10 and y_start is multiplied by 2 */
> + grid.x_start = (grid.x_start / 10) * 10;
> + grid.y_start = (grid.y_start / 2) * 2;
> + grid.y_start = grid.y_start | IPU3_UAPI_GRID_Y_START_EN;
> +}
> +
> /**
> * \brief Configure the IPU3 IPA
> * \param[in] configInfo The IPA configuration data, received from the pipeline
> @@ -461,6 +491,8 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo,
>
> lineDuration_ = sensorInfo_.lineLength * 1.0s / sensorInfo_.pixelRate;
>
> + initAfGrid(configInfo.bdsOutputSize);
> +
> /* Update the camera controls using the new sensor settings. */
> updateControls(sensorInfo_, ctrls_, ipaControls);
>
More information about the libcamera-devel
mailing list