Fixed up Video detector

app/src/main/java/com/example/ueberwachungssystem/Detection/VideoDetector.java

@@ -30,6 +30,7 @@ import org.opencv.core.CvType;
 import org.opencv.core.Mat;
 import org.opencv.core.MatOfPoint;
 import org.opencv.core.Scalar;
+import org.opencv.core.Size;
 import org.opencv.imgproc.Imgproc;
 
 import java.nio.ByteBuffer;
@@ -66,10 +67,6 @@ public class VideoDetector extends Detector {
 
 
     // Parameters
-    private static final float PIXEL_THRESHOLD = 40f;  // Luminosity (brightness channel of YUV_420_888)
-    private static final int BLUR_KERNEL_SIZE = 5;
-    private static final int DILATE_KERNEL_SIZE = 5;
-    private static final float CONTOUR_THRESHOLD = 250;
     private static final float ALARM_THRESHOLD = 0.5f;   // Percent of pixels changed
     private static final long START_DELAY = 1000;   // milliseconds
     private static final android.util.Size IMAGE_RES = new android.util.Size(640, 480);
@@ -140,7 +137,6 @@ public class VideoDetector extends Detector {
         isDetectionRunning = false;
     }
 
-
     /**
      * Permission handling
      */
@@ -172,29 +168,25 @@ public class VideoDetector extends Detector {
                 Image image = imageProxy.getImage();
                 assert image != null;
 
-                if (image != null) {
+                Mat currentMat = extractYChannel(image);
 
-                    Mat mat = extractYChannel(image);
+                Mat mat = currentMat.clone();
+                debugMat(mat, imageView2);
 
-                    debugMat(mat, imageView2);
-                    mat = processImage(mat);
-                    debugMat(mat, imageView1);
+                Mat processed = processImage(mat);
 
-                    int n = 0;
-                    n = countNonZeroPixels(mat);
+                debugMat(processed, imageView1);
 
-                    int pixelCount = image.getWidth() * image.getHeight();
-                    float percentChanged = (float)n / pixelCount;
-                    // report violation
-                    if (percentChanged  * 100 > ALARM_THRESHOLD) {
-                        reportViolation("Video", n);
-                    }
+                int n = countNonZeroPixels(processed);
+                int pixelCount = image.getWidth() * image.getHeight();
+                float percentChanged = (float)n / pixelCount;
+                // report violation
+                if (percentChanged  * 100 > ALARM_THRESHOLD) {
+                    reportViolation("Video", n);
                 }
             }
             imageProxy.close();
         });
-
-
         // Create Preview
         Preview preview = new Preview.Builder().build();
         // Specify which Camera to use
@@ -217,26 +209,42 @@ public class VideoDetector extends Detector {
      * @param image: OpenCV Mat file that should be processed
      */
     private Mat processImage(Mat image){
+
+        // Preprocess Image
+        Mat preprocessed = image.clone();
+        preprocessed = addGaussianBlur(preprocessed, new Size(21, 21));
+        preprocessed = addBlur(preprocessed, new Size(3, 3));
+
         if (previousImage == null) {
-            previousImage = image;
+            previousImage = preprocessed;
             return null;
         }
 
-        Mat mat = addGaussianBlur(image, BLUR_KERNEL_SIZE);
-        mat = thresholdPixels(mat, previousImage);
-        mat = dilateNonZero(mat, DILATE_KERNEL_SIZE);
-        mat = thresholdContourArea(mat, CONTOUR_THRESHOLD);
+        // Process Image
+        Mat processed = preprocessed.clone();
+        processed = thresholdPixels(processed, previousImage, 25);
+        processed = dilateBinaryMat(processed, new Size(3,3));
+        processed = dilateBinaryMat(processed, new Size(3,3));
+        processed = thresholdContourArea(processed, 500);
 
-        previousImage = image.clone();
-        return mat;
+        previousImage = preprocessed.clone();
+        return processed;
+    }
+
+
+    /** OpenCV helper methods **/
+    private Mat addGaussianBlur(Mat inputMat, Size kernelSize){
+        Mat outputMat = new Mat();
+        Imgproc.GaussianBlur(inputMat, outputMat, kernelSize, 0);
+        return outputMat;
+    }
+
+    private Mat addBlur(Mat inputMat, Size kernelSize){
+        Mat outputMat = new Mat();
+        Imgproc.blur(inputMat, outputMat, kernelSize);
+        return outputMat;
     }
 
-    /**
-     * Convert Android Image to OpenCV Mat file with only y-Channel
-     *
-     * @param img: Android Image
-     * @return yChannel of Image in OpenCV Mat Format
-     */
     private Mat extractYChannel(@NonNull Image img) {
         ByteBuffer yBuffer = img.getPlanes()[0].getBuffer();
         byte[] yData = new byte[yBuffer.remaining()];
@@ -248,54 +256,14 @@ public class VideoDetector extends Detector {
         return yMat;
     }
 
-    /**
-     * Threshold all Pixels
-     * @param inputMat: Input Image
-     * @param previousImage: previous Image (openCV Mat)
-     * @return Binary Mat Image
-     */
-    private Mat thresholdPixels(Mat inputMat, Mat previousImage){
+    private Mat thresholdPixels(Mat inputMat, Mat previousImage, int threshold){
         Mat diffImage = new Mat();
         Core.absdiff(inputMat, previousImage, diffImage);
-
         Mat binaryMat = new Mat();
-        Imgproc.threshold(diffImage, binaryMat, VideoDetector.PIXEL_THRESHOLD, 255, Imgproc.THRESH_BINARY);
-
+        Imgproc.threshold(diffImage, binaryMat, threshold, 255, Imgproc.THRESH_BINARY);
         return binaryMat;
     }
 
-    /**
-     * Dilate Pixels of Binary Image
-     * @param inputMat: Input Image
-     * @param kernelSize: kernel Size
-     * @return binary Image with dilated Pixels
-     */
-    private Mat dilateNonZero(Mat inputMat, int kernelSize){
-        Mat dilatedMat = new Mat();
-        Mat kernel = Imgproc.getStructuringElement(Imgproc.MORPH_ELLIPSE, new org.opencv.core.Size(kernelSize, kernelSize));
-        Imgproc.dilate(inputMat, dilatedMat, kernel);
-        return dilatedMat;
-    }
-
-    /**
-     * Add Gaussian Blur to OpenCV Mat Image
-     * @param inputMat: Input Image
-     * @param kernelSize: kernel Size
-     * @return Mat Image
-     */
-    private Mat addGaussianBlur(Mat inputMat, int kernelSize){
-        Mat outputMat = new Mat();
-        Imgproc.GaussianBlur(inputMat, outputMat, new org.opencv.core.Size(kernelSize, kernelSize), 0);
-        return outputMat;
-    }
-
-
-    /**
-     * Filter Contour Areas by Size
-     * @param inputMat: Input Image
-     * @param areaThreshold: Threshold
-     * @return Binary Mat Image
-     */
     private Mat thresholdContourArea(Mat inputMat, float areaThreshold){
         List<MatOfPoint> contours = new ArrayList<>();
         Mat hierarchy = new Mat();
@@ -315,11 +283,13 @@ public class VideoDetector extends Detector {
         return outputMat;
     }
 
-    /**
-     * Count all Pixels that are non Zero
-     * @param inputImage: Input Image in OpenCV Mat Format
-     * @return Count of Pixels that are non zero
-     */
+    private Mat dilateBinaryMat(Mat inputMat, Size kernelSize){
+        Mat dilatedMat = new Mat();
+        Mat kernel = Imgproc.getStructuringElement(Imgproc.MORPH_ELLIPSE, kernelSize);
+        Imgproc.dilate(inputMat, dilatedMat, kernel);
+        return dilatedMat;
+    }
+
     private int countNonZeroPixels(Mat inputImage) {
         if (inputImage != null)
             return Core.countNonZero(inputImage);
@@ -327,11 +297,8 @@ public class VideoDetector extends Detector {
             return 0;
     }
 
-    /**
-     * Show OpenCV Mat on ImageView
-     * @param mat: current OpenCV Mat Image
-     * @param imageView: ImageView xml-Element
-     */
+
+
     private void debugMat(Mat mat, ImageView imageView) {
         if (imageView == null || mat == null)
             return;