Day and night detection based on one or more of illuminant detection, lux level detection, and tiling

摘要

A method, executed at a camera with a Night mode and a Day mode, determines when to switch from Night mode to Day mode using one or more of: illuminant detection (detecting the type of illuminant providing ambient light based on R/G and B/G component ratios of the ambient light), lux detection (detecting the ambient light level), and tiling (performing illuminant detection and/or lux detection for sub-regions of an image sensor array so as to detect localized/narrow beam/point light sources that only illuminate a portion of a scene or are directed at the camera lens). Based on identification of the illuminant type, switching from Night mode to Day mode is done at different lux levels for different types of illuminants. E,g. when the light is due to sunlight or incandescent light switching to Day mode is done at higher lux than when the light is from other sources of visible light.

主权项

1. A method for controlling a camera mode, comprising:
in a camera including a controller, memory storing instructions for execution by the controller, a color sensor array comprising a plurality of sensors, the sensors including first, second and third pixels each having respective peak responses at different respective visible light frequencies, an IR filter, and a lens assembly that is configured to focus light on the sensor array: when the camera mode is a night mode, wherein in the night mode, the IR filter is not interposed between the lens assembly and the sensor array, and the sensor array is exposed to ambient light via the lens assembly without interference by the IR filter:
detecting a first light component of the ambient light by averaging output signals from the first pixels;detecting a second light component of the ambient light by averaging output signals from the second pixels;detecting a third light component of the ambient light by averaging output signals from the third pixels;determining based on respective values of the first, second and third light components whether the ambient light is due to other than an IR light source;detecting the ambient light level;based on a determination that the ambient light that is not filtered by the IR filter is due to other than an IR light source and that the ambient light level exceeds a first lux threshold, initiating a change of the camera mode to a day mode;based on a determination that the ambient light that is not filtered by the IR filter is due to other than an IR light source and that the ambient light threshold does not exceed the first lux threshold, maintaining the camera in the night mode.