Tweaked the corner detectors.

amrzagloul · Sep 12, 2012 · 58f8826 · 58f8826
1 parent cdddaea
commit 58f8826
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Showing 2 changed files with 61 additions and 46 deletions.
diff --git a/examples/FeatureExtractionTest/FeatureExtractionTest/FeatureExtractionAppDelegate.m b/examples/FeatureExtractionTest/FeatureExtractionTest/FeatureExtractionAppDelegate.m
@@ -15,10 +15,10 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
     GPUImagePicture *blackAndWhiteBoxImage = [[GPUImagePicture alloc] initWithImage:inputImage];
 
     [self testHarrisCornerDetectorAgainstPicture:blackAndWhiteBoxImage withName:@"WhiteBoxes"];
+
     [self testNobleCornerDetectorAgainstPicture:blackAndWhiteBoxImage withName:@"WhiteBoxes"];
     [self testShiTomasiCornerDetectorAgainstPicture:blackAndWhiteBoxImage withName:@"WhiteBoxes"];
 
-
     // Testing erosion and dilation
     GPUImageErosionFilter *erosionFilter = [[GPUImageErosionFilter alloc] initWithRadius:4];
     [blackAndWhiteBoxImage removeAllTargets];
@@ -93,18 +93,18 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
 
 - (void)testCornerDetector:(GPUImageHarrisCornerDetectionFilter *)cornerDetector ofName:(NSString *)detectorName againstPicture:(GPUImagePicture *)pictureInput withName:(NSString *)pictureName;
 {
+    cornerDetector.threshold = 0.4;
+    cornerDetector.sensitivity = 4.0;
+    cornerDetector.blurSize = 1.0;
     [pictureInput removeAllTargets];
 
     [pictureInput addTarget:cornerDetector];
 
     GPUImageCrosshairGenerator *crosshairGenerator = [[GPUImageCrosshairGenerator alloc] init];
-    crosshairGenerator.crosshairWidth = 5.0;
+    crosshairGenerator.crosshairWidth = 10.0;
+    [crosshairGenerator setCrosshairColorRed:1.0 green:0.0 blue:0.0];
     [crosshairGenerator forceProcessingAtSize:[pictureInput outputImageSize]];
 
-    [cornerDetector setCornersDetectedBlock:^(GLfloat* cornerArray, NSUInteger cornersDetected, CMTime frameTime) {
-        [crosshairGenerator renderCrosshairsFromArray:cornerArray count:cornersDetected frameTime:frameTime];
-    }];
-
     GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init];
     [blendFilter forceProcessingAtSize:[pictureInput outputImageSize]];
     [pictureInput addTarget:blendFilter];
@@ -113,19 +113,29 @@ - (void)testCornerDetector:(GPUImageHarrisCornerDetectionFilter *)cornerDetector
     [crosshairGenerator addTarget:blendFilter];
 
     [blendFilter prepareForImageCapture];
-    [pictureInput processImage];
 
-    NSUInteger currentImageIndex = 0;
-    for (UIImage *currentImage in cornerDetector.intermediateImages)
-    {
-        [self saveImage:currentImage fileName:[NSString stringWithFormat:@"%@-%@-%d.png", detectorName, pictureName, currentImageIndex]];
+    [cornerDetector setCornersDetectedBlock:^(GLfloat* cornerArray, NSUInteger cornersDetected, CMTime frameTime) {
+        NSLog(@"Number of corners: %d", cornersDetected);
+        [crosshairGenerator renderCrosshairsFromArray:cornerArray count:cornersDetected frameTime:frameTime];
 
-        currentImageIndex++;
-    }
-
-    UIImage *crosshairResult = [blendFilter imageFromCurrentlyProcessedOutput];
+        dispatch_async(dispatch_get_main_queue(), ^{
+            NSUInteger currentImageIndex = 0;
+            for (UIImage *currentImage in cornerDetector.intermediateImages)
+            {
+                [self saveImage:currentImage fileName:[NSString stringWithFormat:@"%@-%@-%d.png", detectorName, pictureName, currentImageIndex]];
+
+                currentImageIndex++;
+            }
+
+            NSLog(@"Save corner image");
+            UIImage *crosshairResult = [blendFilter imageFromCurrentlyProcessedOutput];
+
+            [self saveImage:crosshairResult fileName:[NSString stringWithFormat:@"%@-%@-Crosshairs.png", detectorName, pictureName]];
+        });
+    }];
 
-    [self saveImage:crosshairResult fileName:[NSString stringWithFormat:@"%@-%@-Crosshairs.png", detectorName, pictureName]];
+
+    [pictureInput processImage];
 }
 
 - (void)testHarrisCornerDetectorAgainstPicture:(GPUImagePicture *)pictureInput withName:(NSString *)pictureName;

diff --git a/framework/Source/GPUImageHarrisCornerDetectionFilter.m b/framework/Source/GPUImageHarrisCornerDetectionFilter.m
@@ -141,45 +141,53 @@ - (id)initWithCornerDetectionFragmentShader:(NSString *)cornerDetectionFragmentS
     simpleThresholdFilter = [[GPUImageFilter alloc] initWithFragmentShaderFromString:kGPUImageSimpleThresholdFragmentShaderString];
     [self addFilter:simpleThresholdFilter];
 
+    __unsafe_unretained GPUImageHarrisCornerDetectionFilter *weakSelf = self;
 #ifdef DEBUGFEATUREDETECTION
     weakFilter = simpleThresholdFilter;
     [simpleThresholdFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *filter, CMTime frameTime){
         UIImage *intermediateImage = [weakFilter imageFromCurrentlyProcessedOutput];
         [weakIntermediateImages addObject:intermediateImage];
-    }];
-#endif
-
-    // Sixth pass: compress the thresholded points into the RGBA channels
-    colorPackingFilter = [[GPUImageColorPackingFilter alloc] init];
-    [self addFilter:colorPackingFilter];
-
-
-#ifdef DEBUGFEATUREDETECTION
-    __unsafe_unretained GPUImageHarrisCornerDetectionFilter *weakSelf = self;
-    weakFilter = colorPackingFilter;
-    [colorPackingFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *filter, CMTime frameTime){
-        NSLog(@"Triggered response from compaction filter");
-
-        UIImage *intermediateImage = [weakFilter imageFromCurrentlyProcessedOutput];
-        [weakIntermediateImages addObject:intermediateImage];
 
         [weakSelf extractCornerLocationsFromImageAtFrameTime:frameTime];
     }];
 #else
-    __unsafe_unretained GPUImageHarrisCornerDetectionFilter *weakSelf = self;
-    [colorPackingFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *filter, CMTime frameTime) {
+    [simpleThresholdFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *filter, CMTime frameTime) {
         [weakSelf extractCornerLocationsFromImageAtFrameTime:frameTime];
     }];
 #endif
+
+    // Sixth pass: compress the thresholded points into the RGBA channels
+//    colorPackingFilter = [[GPUImageColorPackingFilter alloc] init];
+//    [self addFilter:colorPackingFilter];
+//
+//    
+//#ifdef DEBUGFEATUREDETECTION
+//    __unsafe_unretained GPUImageHarrisCornerDetectionFilter *weakSelf = self;
+//    weakFilter = colorPackingFilter;
+//    [colorPackingFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *filter, CMTime frameTime){
+//        NSLog(@"Triggered response from compaction filter");
+//        
+//        UIImage *intermediateImage = [weakFilter imageFromCurrentlyProcessedOutput];
+//        [weakIntermediateImages addObject:intermediateImage];
+//        
+//        [weakSelf extractCornerLocationsFromImageAtFrameTime:frameTime];
+//    }];
+//#else
+//    __unsafe_unretained GPUImageHarrisCornerDetectionFilter *weakSelf = self;
+//    [colorPackingFilter setFrameProcessingCompletionBlock:^(GPUImageOutput *filter, CMTime frameTime) {
+//        [weakSelf extractCornerLocationsFromImageAtFrameTime:frameTime];
+//    }];
+//#endif
 
     [derivativeFilter addTarget:blurFilter];    
     [blurFilter addTarget:harrisCornerDetectionFilter];
     [harrisCornerDetectionFilter addTarget:nonMaximumSuppressionFilter];
     [nonMaximumSuppressionFilter addTarget:simpleThresholdFilter];
-    [simpleThresholdFilter addTarget:colorPackingFilter];
+//    [simpleThresholdFilter addTarget:colorPackingFilter];
 
     self.initialFilters = [NSArray arrayWithObjects:derivativeFilter, nil];
-    self.terminalFilter = colorPackingFilter;
+//    self.terminalFilter = colorPackingFilter;
+    self.terminalFilter = simpleThresholdFilter;
 
     self.blurSize = 1.0;
     self.sensitivity = 5.0;
@@ -215,29 +223,26 @@ - (void)extractCornerLocationsFromImageAtFrameTime:(CMTime)frameTime;
 
     CFAbsoluteTime startTime = CFAbsoluteTimeGetCurrent();
 
-    unsigned int imageWidth = imageSize.width * 4.0;
+    unsigned int imageWidth = imageSize.width * 4;
 
-    for (unsigned int currentByte = 0; currentByte < imageByteSize; currentByte++)
+    unsigned int currentByte = 0;
+    unsigned int cornerStorageIndex = 0;
+    while (currentByte < imageByteSize)
     {
         GLubyte colorByte = rawImagePixels[currentByte];
 
-        // Red:   -, -
-        // Green: +, -
-        // Blue:  -, +
-        // Alpha: +. +
-
         if (colorByte > 0)
         {
-//                NSLog(@"(%d, %d): R: %d", scaledXCoordinate, scaledYCoordinate, redByte);
             unsigned int xCoordinate = currentByte % imageWidth;
             unsigned int yCoordinate = currentByte / imageWidth;
 
-            cornersArray[numberOfCorners * 2] = (CGFloat)(xCoordinate / 2) / imageSize.width;
-            cornersArray[numberOfCorners * 2 + 1] = (CGFloat)(yCoordinate * 2) / imageSize.height;
+            cornersArray[cornerStorageIndex++] = (CGFloat)(xCoordinate / 4) / imageSize.width;
+            cornersArray[cornerStorageIndex++] = (CGFloat)(yCoordinate) / imageSize.height;
             numberOfCorners++;
 
             numberOfCorners = MIN(numberOfCorners, 511);
         }
+        currentByte +=4;
     }
 
     CFAbsoluteTime currentFrameTime = (CFAbsoluteTimeGetCurrent() - startTime);