Method and device for balancing foreground-background luminosity

An electronic device comprising:

• an image sensor;
• an illumination component;
• a non-transitory memory;
• one or more processors;
• and
• one or more programs, wherein the one or more programs are stored in the non-transitory memory and configured to be executed by the one or more processors, the one or more programs including instructions for:
• obtaining, by the image sensor, a first image of a scene while the illumination component is set to an inactive state;
• obtaining, by the image sensor, a second image of the scene while the illumination component is set to a pre-flash state;
• generating a foreground estimation of the scene based on relative brightness differences of pixels of the first image and pixels of the second image;
• generating a delta luminosity histogram based on the foreground estimation;
• determining one or more illumination control parameters for the illumination component for a third image of the scene that satisfy a foreground-background balance criterion based on the delta luminosity histogram;
• and
• obtaining, by the image sensor, the third image of the scene while the illumination component is set to an active state in accordance with the one or more illumination control parameters.

A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which, when executed by one or more processors of an electronic device with an image sensor and an illumination component, cause the electronic device to:

• obtain, by the image sensor, a first image of a scene while the illumination component is set to an inactive state;
• obtain, by the image sensor, a second image of the scene while the illumination component is set to a pre-flash state;
• generate a foreground estimation of the scene based on relative brightness differences of pixels of the first image and pixels of the second image;
• generate a delta luminosity histogram based on the foreground estimation;
• determine one or more illumination control parameters for the illumination component for a third image of the scene that satisfy a foreground-background balance criterion based on the delta luminosity histogram;
• and
• obtain, by the image sensor, the third image of the scene while the illumination component is set to an active state in accordance with the one or more illumination control parameters.