Reduced phase sampling for high speed depth sensing

A system comprising:

• an electromagnetic (“EM”) emitter configured to transmit an electromagnetic signal over a wireless medium, wherein the electromagnetic signal includes a plurality of frequencies over a time period that includes a plurality of frames for capturing distance information, wherein the plurality of frames are equally spaced in time, including transmitting the electromagnetic signal over only one of the plurality of frequencies during each frame of the plurality of frames so as to rotate between the frequencies of the plurality of frequencies for each set of consecutive frames in the plurality of frames;
• a time-of-flight (ToF) sensor configured to detect a returned signal that is a reflected version of the transmitted electromagnetic signal, reflected by an object, the depth camera further configured to generate only two sampling frames, each with a respective sampling phase that are not 180 degrees apart;
• and
• a processor with instructions to correlate the detected return signal to the two sampling, frames in order to determine a phase of the returned signal and determine a distance to the object based on the determined phase of the returned signal.

A method of phase time-of-flight (PToF) distance determination, the method comprising:

• transmitting an infrared (IR) signal at each of a plurality of different frequencies, wherein, the plurality of different frequencies includes exactly two frequencies over a time period that includes a plurality of frames for capturing distance information, including transmitting an electromagnetic signal over only one of the two frequencies during each frame of the plurality of frames so as to alternate between the two frequencies for each pair of consecutive frames in the plurality of frames;
• for each of the plurality of different frequencies,
• detecting, by a PToF sensor, a returned IR signal that is a reflected version of the transmitted IR signal, reflected by an object,
• determining a phase of the returned IR signal by correlating the returned signal with a reference signal at each of only two sampling phases that are not 180 degrees apart, and
• determining a phase of the returned signal based on a result of the correlating;
• and
• determining a disambiguated distance to the object based on the determined phase of the returned signal for each of the plurality of different frequencies.