update

docs/sections/Implementation.md

+# Software implementation
+
+The core of the acquisition process is splitted in two AI-modules: the audio analyser and the video analyser. The video analyser takes advantage of computer vision to detect anomalies on the tape area recorded in video.
+
+In simple words the analyser takes in input the video, takes a frame in the middle of the video to find ROIs
\ No newline at end of file

src/main.cpp

@@ -181,24 +181,25 @@ static const string CAPSTAN_TEMPLATE_IMG = "input/capstanBERIO058prova.png";
 static const string CONFIG_FILE = "config/config.json";
 
 /**
- * @brief Get the next frame object
- * 
+ * @brief Get the next frame object.
+ *
  * Whenever we find an Irregularity, we want to skip a lenght equal to the
  * Studer reading head (3 cm = 1.18 inches).
+ *
  * Note the following considerations:
  * - since we are analysing video at 25 fps a frame occurs every 40 ms
  * - at 15 ips we cross 3 cm of tape in 79 ms (2 frames)
  * - at 7.5 ips we cross 3 cm of tape in 157 ms (4 frames)
+ *
  * The considered lengths are the widths of the tape areas.
  * The following condition constitutes a valid approach if the tape areas
  * have widths always equal to the reading head
- * 
+ *
  * @param cap VideoCapture object
  * @param speed tape reading speed
  * @return Frame
  */
 Frame get_next_frame(VideoCapture& cap, float speed, bool skip = false) {
-
     if (skip) {
         int ms_to_skip = speed == 15 ? 79 : 157;
         cap.set(CAP_PROP_POS_MSEC, cap.get(CAP_PROP_POS_MSEC) + ms_to_skip);
@@ -385,8 +386,8 @@ bool findProcessingAreas(Mat myFrame, SceneObject tape, SceneObject capstan) {
         // Draw matches
         Mat img_matches;
         cv::drawMatches(templateShape, keypoints_object, halved_gray_current_frame, keypoints_scene, good_matches,
-                    img_matches, Scalar::all(-1), Scalar::all(-1), vector<char>(),
-                    DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);
+                        img_matches, Scalar::all(-1), Scalar::all(-1), vector<char>(),
+                        DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);
         // Localize the object
         vector<Point2f> obj;
         vector<Point2f> scene;
@@ -508,7 +509,7 @@ Frame get_difference_for_roi(Frame previous, Frame current, RotatedRect roi) {
 }
 
 /**
- * @fn bool frameDifference(cv::Mat prevFrame, cv::Mat currentFrame, int
+ * @fn bool is_frame_different(cv::Mat prevFrame, cv::Mat currentFrame, int
  * msToEnd)
  * @brief Compares two consecutive video frames and establish if there
  * potentially is an Irregularity. The comparison is pixel-wise and based on
@@ -521,7 +522,7 @@ Frame get_difference_for_roi(Frame previous, Frame current, RotatedRect roi) {
  * @return true if a potential Irregularity has been found;
  * @return false otherwise.
  */
-bool frameDifference(cv::Mat prevFrame, cv::Mat currentFrame, int msToEnd, SceneObject capstan, SceneObject tape,
+bool is_frame_different(cv::Mat prevFrame, cv::Mat currentFrame, int msToEnd, SceneObject capstan, SceneObject tape,
                      Args args) {
     bool result = false;
 
@@ -656,31 +657,14 @@ void processing(cv::VideoCapture videoCapture, SceneObject capstan, SceneObject
     int video_current_ms = videoCapture.get(CAP_PROP_POS_MSEC);
     // counters
     int savedFrames = 0;
-    float lastSaved = -160;
-    /* Whenever we find an Irregularity, we want to skip a lenght equal to the
-     * Studer reading head (3 cm = 1.18 inches).
-     * Note the following considerations:
-     * - since we are analysing video at 25 fps a frame occurs every 40 ms
-     * - at 15 ips we cross 3 cm of tape in 79 ms (2 frames)
-     * - at 7.5 ips we cross 3 cm of tape in 157 ms (4 frames)
-     * The considered lengths are the widths of the tape areas.
-     * The following condition constitutes a valid approach if the tape areas
-     * have widths always equal to the reading head
-     */
-    int savingRate = args.speed == 7.5 ? 157 : 79; // [ms]
+    bool irregularity_found = false;
 
     // The first frame of the video won't be processed
-    cv::Mat prevFrame;
-    videoCapture >> prevFrame;
+    cv::Mat prevFrame = get_next_frame(videoCapture, args.speed, irregularity_found);
     firstInstant = video_length_ms - video_current_ms;
 
     while (videoCapture.isOpened()) {
-
-        Frame currentFrame = get_next_frame(videoCapture, args.speed);
-        video_current_ms = videoCapture.get(CAP_PROP_POS_MSEC);
-
-        Frame frame;
-        videoCapture >> frame;
+        Frame frame = get_next_frame(videoCapture, args.speed, irregularity_found);
         video_current_ms = videoCapture.get(CAP_PROP_POS_MSEC);
 
         if (frame.empty()) {
@@ -704,24 +688,20 @@ void processing(cv::VideoCapture videoCapture, SceneObject capstan, SceneObject
         cout << "\rIrregularities: " << savedFrames << ".   ";
         cout << "Remaining video time [mm:ss]: " << minStrToEnd << ":" << secStrToEnd << flush;
 
-        if ((video_current_ms - lastSaved > savingRate) &&
-            frameDifference(prevFrame, frame, msToEnd, capstan, tape, args)) {
-            // An Irregularity has been found!
+        irregularity_found = is_frame_different(prevFrame, frame, msToEnd, capstan, tape, args);
+        if (irregularity_found) {
             auto [odd_frame, even_frame] = frame.deinterlace();
 
-            string timeLabel = getTimeLabel(video_current_ms, ":");
-            string safeTimeLabel = getTimeLabel(video_current_ms, "-");
-
-            string irregularityImageFilename = to_string(savedFrames) + "_" + safeTimeLabel + ".jpg";
+            string irregularityImageFilename =
+                to_string(savedFrames) + "_" + getTimeLabel(video_current_ms, "-") + ".jpg";
             cv::imwrite(irregularityImagesPath / irregularityImageFilename, odd_frame);
 
             // Append Irregularity information to JSON
-            Irregularity irreg = Irregularity(Source::Video, timeLabel);
+            Irregularity irreg = Irregularity(Source::Video, getTimeLabel(video_current_ms, ":"));
             irregularityFileOutput1["Irregularities"] += irreg.to_JSON();
             irregularityFileOutput2["Irregularities"] +=
                 irreg.set_image_URI(irregularityImagesPath.string() + "/" + irregularityImageFilename).to_JSON();
 
-            lastSaved = video_current_ms;
             savedFrames++;
         }
 
@@ -754,7 +734,6 @@ int main(int argc, char** argv) {
     SceneObject tape = SceneObject::from_file(CONFIG_FILE, Object::TAPE);
 
     json irregularityFileInput;
-    cv::Mat myFrame;
 
     const fs::path VIDEO_PATH = args.workingPath / "PreservationAudioVisualFile" / args.filesName;
 
@@ -811,12 +790,11 @@ int main(int argc, char** argv) {
     int frames_number = videoCapture.get(CAP_PROP_FRAME_COUNT);
     // Set frame position to half video length
     videoCapture.set(CAP_PROP_POS_FRAMES, frames_number / 2);
-    // Get frame
-    videoCapture >> myFrame;
+    cv::Mat middle_frame = get_next_frame(videoCapture, args.speed);
 
-    cout << "Video resolution: " << myFrame.cols << "x" << myFrame.rows << endl;
+    cout << "Video resolution: " << middle_frame.cols << "x" << middle_frame.rows << endl;
 
-    bool found = findProcessingAreas(myFrame, tape, capstan);
+    bool found = findProcessingAreas(middle_frame, tape, capstan);
 
     // Reset frame position
     videoCapture.set(CAP_PROP_POS_FRAMES, 0);