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

1 files changed, 377 insertions, 0 deletions

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];
+}