Enhancing imaging performance through the use of active illumination

A method for capturing images of a scene, the method comprising:

• illuminating the scene with a first set of spatially periodic patterns using an illumination system;
• identifying one or more first images of the scene, the one or more first images having a plurality of first modulated components based on modulating the scene with the first set of spatially periodic patterns;
• identifying at least one first modulation frequency for the one or more first images;
• using the identified first modulation frequency to demodulate the modulated components of the one or more first images;
• illuminating the scene with a second set of spatially periodic patterns using the illumination system;
• identifying one or more second images of the scene, the one or more second images having a plurality of second modulated components based on modulating the scene with the second set of spatially periodic patterns;
• identifying at least one second modulation frequency for the one or more second images;
• using the identified second modulation frequency to demodulate the modulated components of the one or more second images;
• and
• identifying a depth of the scene based on the demodulated one or more second images.

A perspective imaging apparatus comprising:

• a perspective illumination system having an illumination center of perspective, the perspective illumination system operable to:
• project a first plurality of illumination patterns onto a scene, the first plurality of illumination patterns defining a first spatial periodicity and a first frequency;
• project a second plurality of illumination patterns onto the scene, the second plurality of illumination patterns defining a second spatial periodicity and a second frequency, the second spatial periodicity shifted spatially from the first spatial periodicity;
• the second plurality of illumination patterns projected after the first plurality of illumination patterns;
• a perspective imager having an imaging center of perspective, the imaging center of perspective and the illumination center of perspective share an optical axis;
• and
• the perspective imaging apparatus operable to:
• receive first image information that includes the first plurality of illumination patterns,
• receive second image information that includes the second plurality of illumination patterns, and
• process the first and second image information to recover a depth map of the scene.

A non-transitory computer readable medium storing instructions to cause a processor to perform operations comprising:

• illuminating the scene with a first set of spatially periodic patterns using an illumination system;
• identifying one or more first images of the scene, the one or more first images having a plurality of first modulated components based on modulating the scene with the first set of spatially periodic patterns;
• identifying at least one first modulation frequency for the one or more first images;
• using the identified first modulation frequency to demodulate the modulated components of the one or more first images;
• illuminating the scene with a second set of spatially periodic patterns using the illumination system;
• identifying one or more second images of the scene, the one or more second images having a plurality of second modulated components based on modulating the scene with the second set of spatially periodic patterns;
• identifying at least one second modulation frequency for the one or more second images;
• using the identified second modulation frequency to demodulate the modulated components of the one or more second images;
• and
• identifying a depth of the scene based on the demodulated one or more second images.