When we preview the camera with PiCamera, the default resolution is 1920x1080 and there is no fisheye effect. We need to reduce the resolution to 368x207 (which is the same 16:9 aspect ratio). To do that we did
camera = picamera.PiCamera()
camera.resolution = (368,207)
For some reason, after we reduce the resolution we see a very strong fish eye effect which isn't there at the full resolution. Alternatively, we can capture the image at full resolution and reduce the size using PIL. This however results in sub-optimal performance.
How do we reduce the image size to 368x207 in picamera without getting a fisheye effect?