1. A computer-implemented method for detecting a camera being out-of-focus, the method comprising: receiving a video frame; performing a pyramid image decomposition on the video frame; determining sharp edge areas, candidate blurry edge areas, and blurry edge areas in each level of the pyramid image decomposition; determining a sharpness value based on at least the sharp edge areas, the sharpness value indicating an overall sharpness of the video frame; determining a blurriness value based on at least the blurry edge areas and the candidate blurry edge areas, the blurriness value indicating an overall blurriness of the video frame; and determining, based on the sharpness value and the blurriness value, whether the video frame is out-of-focus.