public void executePreProcessingStep2(bool student) { if (VisionDLL.executePreProcessingStep2(task, student)) { IntPtr image = VisionDLL.getResultPreProcessingStep2(task); preProcessing2 = VisionDLL.getBitmapFromRGBImage(image); VisionDLL.imageFreeRGB(image); return; } throw new FaceRecognitionTask.FaceRecognitionException("Pre-Processing step 2: failed!"); }