public void executePreProcessingStep3(bool student) { if (VisionDLL.executePreProcessingStep3(task, student)) { IntPtr image = VisionDLL.getResultPreProcessingStep3(task); preProcessing3 = VisionDLL.getBitmapFromRGBImage(image); VisionDLL.imageFreeRGB(image); return; } throw new FaceRecognitionTask.FaceRecognitionException("Pre-Processing step 3: failed!"); }