[BUG] NumPy 2.4 breaks IMX500 example imx500_object_detection_demo.py

[signag]

Bug Description

When running the imx500_object_detection_demo.py with the recently released numpy 2.4.1, the following exception occurs:

Traceback (most recent call last):
  File "/home/sn/prg/picamera2/examples/imx500/imx500_object_detection_demo.py", line 179, in <module>
    last_results = parse_detections(picam2.capture_metadata())
  File "/home/sn/prg/picamera2/examples/imx500/imx500_object_detection_demo.py", line 54, in parse_detections
    Detection(box, category, score, metadata)
    ~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/sn/prg/picamera2/examples/imx500/imx500_object_detection_demo.py", line 21, in __init__
    self.box = imx500.convert_inference_coords(coords, metadata, picam2)
               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/picamera2/devices/imx500/imx500.py", line 376, in convert_inference_coords
    obj = Rectangle(
        *np.maximum(
    ...<2 lines>...
        ).astype(np.int32)
    )
TypeError: __init__(): incompatible constructor arguments. The following argument types are supported:
    1. libcamera._libcamera.Rectangle()
    2. libcamera._libcamera.Rectangle(arg0: int, arg1: int, arg2: libcamera._libcamera.Size)
    3. libcamera._libcamera.Rectangle(arg0: int, arg1: int, arg2: int, arg3: int)
    4. libcamera._libcamera.Rectangle(arg0: libcamera._libcamera.Size)

Invoked with: array([1510], dtype=int32), array([258], dtype=int32), array([791], dtype=int32), array([1186], dtype=int32)
(.venv) sn@raspi06:~/prg/picamera2/examples/imx500 $ 

To Reproduce

• In a picamera2 folder (e.g. ~/prg/picamera2) create a virtual environment
  python -m venv --system-site-packages .venv
• Activate
  source .venv/bin/activate
• Install NumPy
  pip install --ignore-installed numpy
• cd examples/imx500
• python imx500_object_detection_demo.py

Expected behaviour
No exception

Adding the following line to the constructor of class Detection resolves the issue:

coords = (coords[0][0], coords[1][0], coords[2][0], coords[3][0])

Console Output, Screenshots
See above.

Previous NumPy versions (e.g. 2.3.4) showed a deprecation warning:

DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)

Hardware :
Raspberry Pi 5
Camera: imx500

[davidplowman]

This should be fixed in our next branch now if you want to try it, and will be in the next release. Thanks!