[libcamera-devel] [RFC v5] ipa: ipu3: af: Auto focus for dw9719 Surface Go2 VCM
Kate Hsuan
hpa at redhat.com
Thu Jan 20 12:41:02 CET 2022
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.
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).
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).
+*/
+
+/**
+ * \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
+ *
+ * This algorithm is used to determine the position of the lens and get a
+ * focused image. The IPU3 AF accelerator computes the statistics, composed
+ * 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;
+
+/* minimum focus step for searching appropriate focus */
+static constexpr uint32_t coarseSearchStep_ = 10;
+static constexpr uint32_t fineSearchStep_ = 1;
+
+/* 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 */
+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 },
+};
+
+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 */
+ 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)
+{
+ /* 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;
+
+ 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);
--
2.33.1
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