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The robotic arm system uses OpenCV to capture images for object detection. The CameraManager class handles all camera operations including initialization, configuration, and image capture.

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CameraManager Class

The camera system is implemented in arm_system/perception/vision/camera/main.py:5. 
class CameraManager:
    def __init__(self, camera_index: int = 0, width: int = 1280, height: int = 720):
        self.cap = cv2.VideoCapture(camera_index)
        self.cap.set(cv2.CAP_PROP_FRAME_WIDTH, width)
        self.cap.set(cv2.CAP_PROP_FRAME_HEIGHT, height)

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Camera Configuration

The camera is configured with the following default settings:
  • Resolution: 1280x720 pixels
  • Camera Index: 0 (default system camera)
  • Backend: OpenCV VideoCapture

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Resolution Settings

The camera resolution is set using OpenCV properties (arm_system/perception/vision/camera/main.py:8): 
self.cap.set(cv2.CAP_PROP_FRAME_WIDTH, 1280)
self.cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 720)

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Image Capture Process

The capture_image() method handles the complete image capture workflow (arm_system/perception/vision/camera/main.py:11): 
def capture_image(self):
    # Flush camera buffer by grabbing 5 frames
    for _ in range(5):
        self.cap.grab()
    
    # Capture actual frame
    ret, frame = self.cap.read()
    if not ret:
        return None
    
    # Generate filename with timestamp
    current_dir = os.path.dirname(os.path.abspath(__file__))
    timestamp = time.strftime("%Y%m%d-%H%M%S")
    filename = f"{current_dir}/objects_images/{timestamp}.png"
    
    # Create directory if needed
    os.makedirs(os.path.dirname(filename), exist_ok=True)
    
    # Save image
    cv2.imwrite(filename, frame)
    return filename

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Buffer Flushing

The camera flushes 5 frames before capturing to ensure the most recent frame is captured (arm_system/perception/vision/camera/main.py:12): 
for _ in range(5):
    self.cap.grab()

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Storage Location

Captured images are stored in the objects_images/ directory relative to the camera module:
  • Directory: arm_system/perception/vision/camera/objects_images/
  • Filename Format: YYYYMMDD-HHMMSS.png
  • Example: 20260307-143022.png
The directory is automatically created if it doesn’t exist (arm_system/perception/vision/camera/main.py:23).

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Integration with System

The camera is initialized in the CommunicationManager class (arm_system/communication/serial_manager.py:49): 
self.camera = CameraManager(camera_index=camera_index)
When an object is detected during scanning, the camera captures an image for YOLO inference (arm_system/communication/serial_manager.py:178): 
def _handle_object_detection(self, data: dict):
    # Capture image
    img_path = self.camera.capture_image()
    if not img_path:
        log.error("camera could not be captured")
        return
    
    # Process with YOLO
    image, yolo_result = self.object_detect_model.read_image_path(img_path, draw_results=True, save_drawn_img=True)

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Cleanup

The camera is automatically released when the CameraManager object is destroyed (arm_system/perception/vision/camera/main.py:28): 
def __del__(self):
    self.cap.release()

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