Why is there overlayed square and number on Raspberry Pi camera image taken using MATLAB? How to remove?

%%UPDATE: Using wcam instead of cameraboard solved my issue for now. But I would still like to know how to solve issue with cameraboard()

I took a photo using my RaspberryPi camera through Matlab and the image I get has a square and number 0 on it. What causes this and how to remove it? I've attached the image and the

mypi=raspi('raspberrypi');
mycam = cameraboard(mypi)
img = snapshot(mycam);
    imagesc(img);
    drawnow

code used.

Answer 1

[yanqi liu]

mypi=raspi('raspberrypi');
mycam = cameraboard(mypi)
mycam.ROI = [0.50 0.50 0.33 0.33]
img = snapshot(mycam);
imagesc(img); axis off;
drawnow

Answer 2

[Obed Rios]

It appears I have that strange rectangle when using my camera board with Matlab after using raspistill with ROI. After rebooting my Rpi, the rectangle was gone. Best regards

[Stuart Johnson]

I could have sworn this did not work the first couple of times I tried it. But, now the mystery box is gone. Sure seems something is trying to turn on some object detection / annotation pipeline!