tracker/pt: move impl bits away from pt-base

13 files changed, 887 insertions, 0 deletions

diff --git a/tracker-pt/module/CMakeLists.txt b/tracker-pt/module/CMakeLists.txt
new file mode 100644
index 00000000..1d1b4458
--- /dev/null
+++ b/tracker-pt/module/CMakeLists.txt
@@ -0,0 +1,6 @@
+find_package(OpenCV 3.0 QUIET)
+if(OpenCV_FOUND)
+    otr_module(tracker-pt)
+    target_link_libraries(opentrack-tracker-pt opentrack-tracker-pt-base)
+    target_include_directories(opentrack-tracker-pt PRIVATE "${CMAKE_SOURCE_DIR}/tracker-pt")
+endif()
diff --git a/tracker-pt/module/Resources/Logo_IR.png b/tracker-pt/module/Resources/Logo_IR.png
new file mode 100644
index 00000000..95032a25
--- /dev/null
+++ b/tracker-pt/module/Resources/Logo_IR.png
diff --git a/tracker-pt/module/camera.cpp b/tracker-pt/module/camera.cpp
new file mode 100644
index 00000000..ba4583da
--- /dev/null
+++ b/tracker-pt/module/camera.cpp
@@ -0,0 +1,171 @@
+/* Copyright (c) 2012 Patrick Ruoff
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ */
+
+#include "camera.h"
+#include "frame.hpp"
+
+#include "compat/sleep.hpp"
+#include "compat/camera-names.hpp"
+#include "compat/math-imports.hpp"
+
+#include <opencv2/imgproc.hpp>
+
+#include "cv/video-property-page.hpp"
+
+using namespace pt_module;
+
+Camera::Camera(const QString& module_name) : s { module_name }
+{
+}
+
+QString Camera::get_desired_name() const
+{
+    return desired_name;
+}
+
+QString Camera::get_active_name() const
+{
+    return active_name;
+}
+
+void Camera::show_camera_settings()
+{
+    const int idx = camera_name_to_index(s.camera_name);
+
+    if (bool(*this))
+        video_property_page::show_from_capture(*cap, idx);
+    else
+    {
+        video_property_page::show(idx);
+    }
+}
+
+Camera::result Camera::get_info() const
+{
+    if (cam_info.res_x == 0 || cam_info.res_y == 0)
+        return result(false, pt_camera_info());
+    return result(true, cam_info);
+}
+
+Camera::result Camera::get_frame(pt_frame& frame_)
+{
+    cv::Mat& frame = frame_.as<Frame>()->mat;
+
+    const bool new_frame = _get_frame(frame);
+
+    if (new_frame)
+    {
+        const double dt = t.elapsed_seconds();
+        t.start();
+
+        // measure fps of valid frames
+        constexpr double RC = .1; // seconds
+        const double alpha = dt/(dt + RC);
+
+        if (dt_mean < dt_eps)
+            dt_mean = dt;
+        else
+            dt_mean = (1-alpha) * dt_mean + alpha * dt;
+
+        cam_info.fps = dt_mean > dt_eps ? 1 / dt_mean : 0;
+        cam_info.res_x = frame.cols;
+        cam_info.res_y = frame.rows;
+        cam_info.fov = fov;
+
+        return result(true, cam_info);
+    }
+    else
+        return result(false, pt_camera_info());
+}
+
+pt_camera_open_status Camera::start(int idx, int fps, int res_x, int res_y)
+{
+    if (idx >= 0 && fps >= 0 && res_x >= 0 && res_y >= 0)
+    {
+        if (cam_desired.idx != idx ||
+            cam_desired.fps != fps ||
+            cam_desired.res_x != res_x ||
+            cam_desired.res_y != res_y ||
+            !cap || !cap->isOpened() || !cap->grab())
+        {
+            stop();
+
+            desired_name = get_camera_names().value(idx);
+            cam_desired.idx = idx;
+            cam_desired.fps = fps;
+            cam_desired.res_x = res_x;
+            cam_desired.res_y = res_y;
+            cam_desired.fov = fov;
+
+            cap = camera_ptr(new cv::VideoCapture(cam_desired.idx));
+
+            if (cam_desired.res_x)
+                cap->set(cv::CAP_PROP_FRAME_WIDTH,  cam_desired.res_x);
+            if (cam_desired.res_y)
+                cap->set(cv::CAP_PROP_FRAME_HEIGHT, cam_desired.res_y);
+            if (cam_desired.fps)
+                cap->set(cv::CAP_PROP_FPS, cam_desired.fps);
+
+            if (cap->isOpened() && cap->grab())
+            {
+                cam_info = pt_camera_info();
+                active_name = QString();
+                cam_info.idx = idx;
+                dt_mean = 0;
+                active_name = desired_name;
+
+                t.start();
+
+                return cam_open_ok_change;
+            }
+            else
+            {
+                stop();
+                return cam_open_error;
+            }
+        }
+
+        return cam_open_ok_no_change;
+    }
+
+    stop();
+    return cam_open_error;
+}
+
+void Camera::stop()
+{
+    cap = nullptr;
+    desired_name = QString();
+    active_name = QString();
+    cam_info = pt_camera_info();
+    cam_desired = pt_camera_info();
+}
+
+bool Camera::_get_frame(cv::Mat& frame)
+{
+    if (cap && cap->isOpened())
+    {
+        for (int i = 0; i < 5; i++)
+        {
+            if (cap->read(frame))
+                return true;
+            portable::sleep(1);
+        }
+    }
+    return false;
+}
+
+void Camera::camera_deleter::operator()(cv::VideoCapture* cap)
+{
+    if (cap)
+    {
+        if (cap->isOpened())
+            cap->release();
+        delete cap;
+    }
+}
+
diff --git a/tracker-pt/module/camera.h b/tracker-pt/module/camera.h
new file mode 100644
index 00000000..96234840
--- /dev/null
+++ b/tracker-pt/module/camera.h
@@ -0,0 +1,69 @@
+/* Copyright (c) 2012 Patrick Ruoff
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ */
+
+#pragma once
+
+#include "pt-api.hpp"
+
+#include "compat/timer.hpp"
+
+#include <functional>
+#include <memory>
+#include <tuple>
+
+#include <opencv2/core.hpp>
+#include <opencv2/videoio.hpp>
+
+#include <QString>
+
+namespace pt_module {
+
+struct Camera final : pt_camera
+{
+    Camera(const QString& module_name);
+
+    pt_camera_open_status start(int idx, int fps, int res_x, int res_y) override;
+    void stop() override;
+
+    result get_frame(pt_frame& Frame) override;
+    result get_info() const override;
+
+    pt_camera_info get_desired() const override { return cam_desired; }
+    QString get_desired_name() const override;
+    QString get_active_name() const override;
+
+    operator bool() const override { return cap && cap->isOpened(); }
+
+    void set_fov(double value) override { fov = value; }
+    void show_camera_settings() override;
+
+private:
+    warn_result_unused bool _get_frame(cv::Mat& Frame);
+
+    double dt_mean = 0, fov = 30;
+
+    Timer t;
+
+    pt_camera_info cam_info;
+    pt_camera_info cam_desired;
+    QString desired_name, active_name;
+
+    struct camera_deleter final
+    {
+        void operator()(cv::VideoCapture* cap);
+    };
+
+    using camera_ptr = std::unique_ptr<cv::VideoCapture, camera_deleter>;
+
+    camera_ptr cap;
+
+    pt_settings s;
+
+    static constexpr inline double dt_eps = 1./384;
+};
+
+} // ns pt_module
diff --git a/tracker-pt/module/frame.cpp b/tracker-pt/module/frame.cpp
new file mode 100644
index 00000000..e403af07
--- /dev/null
+++ b/tracker-pt/module/frame.cpp
@@ -0,0 +1,83 @@
+#include "frame.hpp"
+
+#include "compat/math.hpp"
+
+#include <cstring>
+#include <tuple>
+
+#include <opencv2/imgproc.hpp>
+
+using namespace pt_module;
+
+Preview& Preview::operator=(const pt_frame& frame_)
+{
+    const cv::Mat& frame = frame_.as_const<const Frame>()->mat;
+    ensure_size(frame_copy, frame_out.cols, frame_out.rows, CV_8UC3);
+
+    if (frame.channels() != 3)
+    {
+        once_only(qDebug() << "tracker/pt: camera frame depth: 3 !=" << frame.channels());
+        return *this;
+    }
+
+    const bool need_resize = frame.cols != frame_out.cols || frame.rows != frame_out.rows;
+    if (need_resize)
+        cv::resize(frame, frame_copy, cv::Size(frame_out.cols, frame_out.rows), 0, 0, cv::INTER_NEAREST);
+    else
+        frame.copyTo(frame_copy);
+
+    return *this;
+}
+
+Preview::Preview(int w, int h)
+{
+    ensure_size(frame_out, w, h, CV_8UC4);
+
+    frame_out.setTo(cv::Scalar(0, 0, 0, 0));
+}
+
+QImage Preview::get_bitmap()
+{
+    int stride = frame_out.step.p[0];
+
+    if (stride < 64 || stride < frame_out.cols * 4)
+    {
+        once_only(qDebug() << "bad stride" << stride
+                           << "for bitmap size" << frame_copy.cols << frame_copy.rows);
+        return QImage();
+    }
+
+    cv::cvtColor(frame_copy, frame_out, cv::COLOR_BGR2BGRA);
+
+    return QImage((const unsigned char*) frame_out.data,
+                  frame_out.cols, frame_out.rows,
+                  stride,
+                  QImage::Format_ARGB32);
+}
+
+void Preview::draw_head_center(double x, double y)
+{
+    double px_, py_;
+
+    std::tie(px_, py_) = to_pixel_pos(x, y, frame_copy.cols, frame_copy.rows);
+
+    int px = iround(px_), py = iround(py_);
+
+    constexpr int len = 9;
+
+    static const cv::Scalar color(0, 255, 255);
+    cv::line(frame_copy,
+             cv::Point(px - len, py),
+             cv::Point(px + len, py),
+             color, 1);
+    cv::line(frame_copy,
+             cv::Point(px, py - len),
+             cv::Point(px, py + len),
+             color, 1);
+}
+
+void Preview::ensure_size(cv::Mat& frame, int w, int h, int type)
+{
+    if (frame.cols != w || frame.rows != h)
+        frame = cv::Mat(h, w, type);
+}
diff --git a/tracker-pt/module/frame.hpp b/tracker-pt/module/frame.hpp
new file mode 100644
index 00000000..9e4f809a
--- /dev/null
+++ b/tracker-pt/module/frame.hpp
@@ -0,0 +1,36 @@
+#pragma once
+
+#include "pt-api.hpp"
+
+#include <opencv2/core.hpp>
+#include <QImage>
+
+namespace pt_module {
+
+struct Frame final : pt_frame
+{
+    cv::Mat mat;
+
+    operator const cv::Mat&() const& { return mat; }
+    operator cv::Mat&() & { return mat; }
+};
+
+struct Preview final : pt_preview
+{
+    Preview(int w, int h);
+
+    Preview& operator=(const pt_frame& frame) override;
+    QImage get_bitmap() override;
+    void draw_head_center(double x, double y) override;
+
+    operator cv::Mat&() { return frame_copy; }
+    operator cv::Mat const&() const { return frame_copy; }
+
+private:
+    static void ensure_size(cv::Mat& frame, int w, int h, int type);
+
+    bool fresh = true;
+    cv::Mat frame_copy, frame_color, frame_out;
+};
+
+} // ns pt_module
diff --git a/tracker-pt/module/ftnoir_tracker_pt.qrc b/tracker-pt/module/ftnoir_tracker_pt.qrc
new file mode 100644
index 00000000..dfeb7369
--- /dev/null
+++ b/tracker-pt/module/ftnoir_tracker_pt.qrc
@@ -0,0 +1,5 @@
+<RCC>
+    <qresource prefix="/">
+        <file>Resources/Logo_IR.png</file>
+    </qresource>
+</RCC>
diff --git a/tracker-pt/module/lang/nl_NL.ts b/tracker-pt/module/lang/nl_NL.ts
new file mode 100644
index 00000000..9e739505
--- /dev/null
+++ b/tracker-pt/module/lang/nl_NL.ts
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1" language="nl_NL">
+</TS>
diff --git a/tracker-pt/module/lang/ru_RU.ts b/tracker-pt/module/lang/ru_RU.ts
new file mode 100644
index 00000000..f62cf2e1
--- /dev/null
+++ b/tracker-pt/module/lang/ru_RU.ts
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1" language="ru_RU">
+</TS>
diff --git a/tracker-pt/module/lang/stub.ts b/tracker-pt/module/lang/stub.ts
new file mode 100644
index 00000000..6401616d
--- /dev/null
+++ b/tracker-pt/module/lang/stub.ts
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.1">
+</TS>
diff --git a/tracker-pt/module/module.cpp b/tracker-pt/module/module.cpp
new file mode 100644
index 00000000..5c298ca5
--- /dev/null
+++ b/tracker-pt/module/module.cpp
@@ -0,0 +1,69 @@
+#include "ftnoir_tracker_pt.h"
+#include "api/plugin-api.hpp"
+
+#include "camera.h"
+#include "frame.hpp"
+#include "point_extractor.h"
+#include "ftnoir_tracker_pt_dialog.h"
+
+#include "pt-api.hpp"
+
+#include <memory>
+
+static const QString module_name = "tracker-pt";
+
+using namespace pt_module;
+
+struct pt_module_traits final : pt_runtime_traits
+{
+    pointer<pt_camera> make_camera() const override
+    {
+        return pointer<pt_camera>(new Camera(module_name));
+    }
+
+    pointer<pt_point_extractor> make_point_extractor() const override
+    {
+        return pointer<pt_point_extractor>(new PointExtractor(module_name));
+    }
+
+    QString get_module_name() const override
+    {
+        return module_name;
+    }
+
+    pointer<pt_frame> make_frame() const override
+    {
+        return pointer<pt_frame>(new Frame);
+    }
+
+    pointer<pt_preview> make_preview(int w, int h) const override
+    {
+        return pointer<pt_preview>(new Preview(w, h));
+    }
+};
+
+struct tracker_pt : Tracker_PT
+{
+    tracker_pt() : Tracker_PT(pointer<pt_runtime_traits>(new pt_module_traits))
+    {
+    }
+};
+
+struct dialog_pt : TrackerDialog_PT
+{
+    dialog_pt();
+};
+
+class metadata_pt : public Metadata
+{
+    QString name() { return _("PointTracker 1.1"); }
+    QIcon icon() { return QIcon(":/Resources/Logo_IR.png"); }
+};
+
+// ns pt_module
+
+using namespace pt_module;
+
+dialog_pt::dialog_pt() : TrackerDialog_PT(module_name) {}
+
+OPENTRACK_DECLARE_TRACKER(tracker_pt, dialog_pt, metadata_pt)
diff --git a/tracker-pt/module/point_extractor.cpp b/tracker-pt/module/point_extractor.cpp
new file mode 100644
index 00000000..b67c4036
--- /dev/null
+++ b/tracker-pt/module/point_extractor.cpp
@@ -0,0 +1,377 @@
+/* Copyright (c) 2012 Patrick Ruoff
+ * Copyright (c) 2015-2017 Stanislaw Halik <sthalik@misaki.pl>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ */
+
+#include "point_extractor.h"
+#include "point_tracker.h"
+#include "frame.hpp"
+
+#include "cv/numeric.hpp"
+#include "compat/math.hpp"
+
+#include <opencv2/videoio.hpp>
+
+#undef PREVIEW
+//#define PREVIEW
+
+#if defined PREVIEW
+#   include <opencv2/highgui.hpp>
+#endif
+
+#include <cmath>
+#include <algorithm>
+#include <cinttypes>
+#include <memory>
+
+#include <QDebug>
+
+using namespace types;
+using namespace pt_module;
+
+/*
+http://en.wikipedia.org/wiki/Mean-shift
+In this application the idea, is to eliminate any bias of the point estimate 
+which is introduced by the rather arbitrary thresholded area. One must recognize
+that the thresholded area can only move in one pixel increments since it is
+binary. Thus, its center of mass might make "jumps" as pixels are added/removed
+from the thresholded area.
+With mean-shift, a moving "window" or kernel is multiplied with the gray-scale
+image, and the COM is calculated of the result. This is iterated where the
+kernel center is set the previously computed COM. Thus, peaks in the image intensity
+distribution "pull" the kernel towards themselves. Eventually it stops moving, i.e.
+then the computed COM coincides with the kernel center. We hope that the 
+corresponding location is a good candidate for the extracted point.
+The idea similar to the window scaling suggested in  Berglund et al. "Fast, bias-free 
+algorithm for tracking single particles with variable size and shape." (2008).
+*/
+static cv::Vec2d MeanShiftIteration(const cv::Mat &frame_gray, const vec2 &current_center, f filter_width)
+{
+    // Most amazingly this function runs faster with doubles than with floats.
+    const f s = 1.0 / filter_width;
+
+    f m = 0;
+    vec2 com { 0, 0  };
+    for (int i = 0; i < frame_gray.rows; i++)
+    {
+        auto frame_ptr = (uint8_t const* restrict_ptr)frame_gray.ptr(i);
+        for (int j = 0; j < frame_gray.cols; j++)
+        {
+            f val = frame_ptr[j];
+            val = val * val; // taking the square wights brighter parts of the image stronger.
+            {
+                f dx = (j - current_center[0])*s;
+                f dy = (i - current_center[1])*s;
+                f f = std::fmax(0, 1 - dx*dx - dy*dy);
+                val *= f;
+            }
+            m += val;
+            com[0] += j * val;
+            com[1] += i * val;
+        }
+    }
+    if (m > f(.1))
+    {
+        com *= f(1) / m;
+        return com;
+    }
+    else
+        return current_center;
+}
+
+PointExtractor::PointExtractor(const QString& module_name) : s(module_name)
+{
+    blobs.reserve(max_blobs);
+}
+
+void PointExtractor::ensure_channel_buffers(const cv::Mat& orig_frame)
+{
+    if (ch[0].rows != orig_frame.rows || ch[0].cols != orig_frame.cols)
+        for (unsigned k = 0; k < 3; k++)
+            ch[k] = cv::Mat1b(orig_frame.rows, orig_frame.cols);
+}
+
+void PointExtractor::ensure_buffers(const cv::Mat& frame)
+{
+    const int W = frame.cols, H = frame.rows;
+
+    if (frame_gray.rows != W || frame_gray.cols != H)
+    {
+        frame_gray = cv::Mat1b(H, W);
+        frame_bin = cv::Mat1b(H, W);
+        frame_blobs = cv::Mat1b(H, W);
+    }
+}
+
+void PointExtractor::extract_single_channel(const cv::Mat& orig_frame, int idx, cv::Mat& dest)
+{
+    ensure_channel_buffers(orig_frame);
+
+    const int from_to[] = {
+        idx, 0,
+    };
+
+    cv::mixChannels(&orig_frame, 1, &dest, 1, from_to, 1);
+}
+
+void PointExtractor::extract_channels(const cv::Mat& orig_frame, const int* order, int order_npairs)
+{
+    ensure_channel_buffers(orig_frame);
+
+    cv::mixChannels(&orig_frame, 1, (cv::Mat*) ch, order_npairs, order, order_npairs);
+}
+
+void PointExtractor::color_to_grayscale(const cv::Mat& frame, cv::Mat1b& output)
+{
+    switch (s.blob_color)
+    {
+    case pt_color_blue_only:
+    {
+        extract_single_channel(frame, 0, output);
+        break;
+    }
+    case pt_color_red_only:
+    {
+        extract_single_channel(frame, 2, output);
+        break;
+    }
+    case pt_color_average:
+    {
+        const int W = frame.cols, H = frame.rows;
+        const cv::Mat tmp = frame.reshape(1, W * H);
+        cv::Mat output_ = output.reshape(1, W * H);
+        cv::reduce(tmp, output_, 1, cv::REDUCE_AVG);
+        break;
+    }
+    default:
+        once_only(qDebug() << "wrong pt_color_type enum value" << int(s.blob_color));
+        /*FALLTHROUGH*/
+    case pt_color_natural:
+        cv::cvtColor(frame, output, cv::COLOR_BGR2GRAY);
+        break;
+    }
+}
+
+void PointExtractor::threshold_image(const cv::Mat& frame_gray, cv::Mat1b& output)
+{
+    const int threshold_slider_value = s.threshold_slider.to<int>();
+
+    if (!s.auto_threshold)
+    {
+        cv::threshold(frame_gray, output, threshold_slider_value, 255, cv::THRESH_BINARY);
+    }
+    else
+    {
+        const int hist_size = 256;
+        const float ranges_[] = { 0, 256 };
+        float const* ranges = (const float*) ranges_;
+
+        cv::calcHist(&frame_gray,
+                     1,
+                     nullptr,
+                     cv::noArray(),
+                     hist,
+                     1,
+                     (int const*) &hist_size,
+                     &ranges);
+
+        const f radius = (f) threshold_radius_value(frame_gray.cols, frame_gray.rows, threshold_slider_value);
+
+        auto ptr = (float const* const restrict_ptr) hist.ptr(0);
+        const unsigned area = uround(3 * M_PI * radius*radius);
+        const unsigned sz = unsigned(hist.cols * hist.rows);
+        unsigned thres = 32;
+        for (unsigned i = sz-1, cnt = 0; i > 32; i--)
+        {
+            cnt += ptr[i];
+            if (cnt >= area)
+                break;
+            thres = i;
+        }
+
+        cv::threshold(frame_gray, output, thres, 255, CV_THRESH_BINARY);
+    }
+}
+
+void PointExtractor::extract_points(const pt_frame& frame_, pt_preview& preview_frame_, std::vector<vec2>& points)
+{
+    const cv::Mat& frame = frame_.as_const<Frame>()->mat;
+    cv::Mat& preview_frame = *preview_frame_.as<Preview>();
+
+    ensure_buffers(frame);
+    color_to_grayscale(frame, frame_gray);
+
+#if defined PREVIEW
+    cv::imshow("capture", frame_gray);
+    cv::waitKey(1);
+#endif
+
+    threshold_image(frame_gray, frame_bin);
+
+    blobs.clear();
+    frame_bin.copyTo(frame_blobs);
+
+    const f region_size_min = s.min_point_size;
+    const f region_size_max = s.max_point_size;
+
+    unsigned idx = 0;
+    for (int y=0; y < frame_blobs.rows; y++)
+    {
+        const unsigned char* ptr_bin = frame_blobs.ptr(y);
+        for (int x=0; x < frame_blobs.cols; x++)
+        {
+            if (ptr_bin[x] != 255)
+                continue;
+            idx = blobs.size() + 1;
+
+            cv::Rect rect;
+            cv::floodFill(frame_blobs,
+                          cv::Point(x,y),
+                          cv::Scalar(idx),
+                          &rect,
+                          cv::Scalar(0),
+                          cv::Scalar(0),
+                          4 | cv::FLOODFILL_FIXED_RANGE);
+
+            unsigned cnt = 0;
+            unsigned norm = 0;
+
+            const int ymax = rect.y+rect.height,
+                      xmax = rect.x+rect.width;
+
+            for (int i=rect.y; i < ymax; i++)
+            {
+                unsigned char const* const restrict_ptr ptr_blobs = frame_blobs.ptr(i);
+                unsigned char const* const restrict_ptr ptr_gray = frame_gray.ptr(i);
+                for (int j=rect.x; j < xmax; j++)
+                {
+                    if (ptr_blobs[j] != idx)
+                        continue;
+
+                    //ptr_blobs[j] = 0;
+                    norm += ptr_gray[j];
+                    cnt++;
+                }
+            }
+
+            const double radius = std::sqrt(cnt / M_PI);
+            if (radius > region_size_max || radius < region_size_min)
+                continue;
+
+            blobs.emplace_back(radius,
+                               vec2(rect.width/2., rect.height/2.),
+                               std::pow(f(norm), f(1.1))/cnt,
+                               rect);
+
+            if (idx >= max_blobs)
+                goto end;
+
+            // XXX we could go to the next scanline unless the points are really small.
+            // i'd expect each point being present on at least one unique scanline
+            // but it turns out some people are using 2px points -sh 20180110
+#if BROKEN && 0
+            break;
+#endif
+        }
+    }
+end:
+
+    const int W = frame_gray.cols;
+    const int H = frame_gray.rows;
+
+    const unsigned sz = blobs.size();
+
+    std::sort(blobs.begin(), blobs.end(), [](const blob& b1, const blob& b2) { return b2.brightness < b1.brightness; });
+
+    for (idx = 0; idx < sz; ++idx)
+    {
+        blob &b = blobs[idx];
+        cv::Rect rect = b.rect;
+
+        rect.x -= rect.width / 2;
+        rect.y -= rect.height / 2;
+        rect.width *= 2;
+        rect.height *= 2;
+        rect &= cv::Rect(0, 0, W, H);  // crop at frame boundaries
+
+        cv::Mat frame_roi = frame_gray(rect);
+
+        // smaller values mean more changes. 1 makes too many changes while 1.5 makes about .1
+        static constexpr f radius_c = f(1.75);
+
+        const f kernel_radius = b.radius * radius_c;
+        vec2 pos(rect.width/2., rect.height/2.); // position relative to ROI.
+
+        for (int iter = 0; iter < 10; ++iter)
+        {
+            vec2 com_new = MeanShiftIteration(frame_roi, pos, kernel_radius);
+            vec2 delta = com_new - pos;
+            pos = com_new;
+            if (delta.dot(delta) < 1e-2)
+                break;
+        }
+
+        b.pos[0] = pos[0] + rect.x;
+        b.pos[1] = pos[1] + rect.y;
+    }
+
+    for (unsigned k = 0; k < blobs.size(); k++)
+    {
+        blob& b = blobs[k];
+
+        const f dpi = preview_frame.cols / f(320);
+        const f offx = 10 * dpi, offy = 7.5 * dpi;
+
+        const f cx = preview_frame.cols / f(frame.cols),
+                cy = preview_frame.rows / f(frame.rows),
+                c_ = (cx+cy)/2;
+
+        static constexpr unsigned fract_bits = 16;
+        static constexpr double c_fract(1 << fract_bits);
+
+        cv::Point p(iround(b.pos[0] * cx * c_fract), iround(b.pos[1] * cy * c_fract));
+
+        auto circle_color = k >= PointModel::N_POINTS
+                            ? cv::Scalar(192, 192, 192)
+                            : cv::Scalar(255, 255, 0);
+
+        const f overlay_size = dpi > 1.5 ? 2 : 1;
+
+        cv::circle(preview_frame, p, iround((b.radius + 3.3) * c_ * c_fract), circle_color, overlay_size, cv::LINE_AA, fract_bits);
+
+        char buf[16];
+        buf[sizeof(buf)-1] = '\0';
+        std::snprintf(buf, sizeof(buf) - 1, "%.2fpx", b.radius);
+
+        auto text_color = k >= PointModel::N_POINTS
+                          ? cv::Scalar(160, 160, 160)
+                          : cv::Scalar(0, 0, 255);
+
+        cv::Point pos(iround(b.pos[0]*cx+offx), iround(b.pos[1]*cy+offy));
+        cv::putText(preview_frame, buf, pos,
+                    cv::FONT_HERSHEY_PLAIN, overlay_size, text_color,
+                    1);
+    }
+
+    // End of mean shift code. At this point, blob positions are updated with hopefully less noisy less biased values.
+    points.reserve(max_blobs);
+    points.clear();
+
+    for (const auto& b : blobs)
+    {
+        // note: H/W is equal to fx/fy
+
+        vec2 p;
+        std::tie(p[0], p[1]) = to_screen_pos(b.pos[0], b.pos[1], W, H);
+        points.push_back(p);
+    }
+}
+
+blob::blob(f radius, const vec2& pos, f brightness, const cv::Rect& rect) :
+    radius(radius), brightness(brightness), pos(pos), rect(rect)
+{
+    //qDebug() << "radius" << radius << "pos" << pos[0] << pos[1];
+}
diff --git a/tracker-pt/module/point_extractor.h b/tracker-pt/module/point_extractor.h
new file mode 100644
index 00000000..1b6f55a2
--- /dev/null
+++ b/tracker-pt/module/point_extractor.h
@@ -0,0 +1,59 @@
+/* Copyright (c) 2012 Patrick Ruoff
+ * Copyright (c) 2015-2016 Stanislaw Halik <sthalik@misaki.pl>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ */
+
+#pragma once
+
+#include "pt-api.hpp"
+
+#include <vector>
+
+#include <opencv2/core.hpp>
+#include <opencv2/imgproc.hpp>
+
+namespace pt_module {
+
+using namespace types;
+
+struct blob
+{
+    f radius, brightness;
+    vec2 pos;
+    cv::Rect rect;
+
+    blob(f radius, const vec2& pos, f brightness, const cv::Rect& rect);
+};
+
+class PointExtractor final : public pt_point_extractor
+{
+public:
+    // extracts points from frame and draws some processing info into frame, if draw_output is set
+    // dt: time since last call in seconds
+    void extract_points(const pt_frame& frame, pt_preview& preview_frame, std::vector<vec2>& points) override;
+    PointExtractor(const QString& module_name);
+private:
+    static constexpr int max_blobs = 16;
+
+    pt_settings s;
+
+    cv::Mat1b frame_gray, frame_bin, frame_blobs;
+    cv::Mat1f hist;
+    std::vector<blob> blobs;
+    cv::Mat1b ch[3];
+
+    void ensure_channel_buffers(const cv::Mat& orig_frame);
+    void ensure_buffers(const cv::Mat& frame);
+
+    void extract_single_channel(const cv::Mat& orig_frame, int idx, cv::Mat& dest);
+    void extract_channels(const cv::Mat& orig_frame, const int* order, int order_npairs);
+
+    void color_to_grayscale(const cv::Mat& frame, cv::Mat1b& output);
+    void threshold_image(const cv::Mat& frame_gray, cv::Mat1b& output);
+};
+
+} // ns impl
+