Determining depth using multiple modulation frequencies

A method comprising:

• configuring a time-of-flight sensor in a first configuration, the first configuration having an associated first modulation frequency;
• emitting, with the time-of-flight sensor in the first configuration, first emitted light at the first modulation frequency;
• receiving, at the time-of-flight sensor, first return light associated with the first emitted light;
• determining, based at least in part on the first return light, first depth information about a surface;
• determining, based on the first depth information, an estimated depth of the surface from the time-of-flight sensor, the estimated depth not exceeding a first nominal maximum depth of the time-of-flight sensor associated with the first configuration;
• configuring the time-of-flight sensor in a second configuration having an associated second modulation frequency higher than the first modulation frequency;
• emitting, with the time-of-flight sensor in the second configuration, second emitted light at the second modulation frequency;
• receiving, at the time-of-flight sensor, second return light associated with the second emitted light;
• determining, based at least in part on the second return light, second data comprising second depth information about the surface;
• determining, based at least in part on the second depth information, a plurality of candidate depths of the surface, the plurality of candidate depths comprising a nominal depth not exceeding a second nominal maximum depth of the time-of-flight sensor associated with the second configuration and a first candidate depth comprising a sum of the nominal depth and the second nominal maximum depth;
• and
• determining a measured depth of the surface as one of the plurality of candidate depths closest to the estimated depth.

A system comprising:

• one or more processors;
• and
• computer-readable storage media storing instructions executable by the one or more processors to perform acts comprising:
• causing a time-of-flight sensor to be configured in a first configuration, the first configuration having an associated first modulation frequency;
• causing the time-of-flight sensor to emit, with the time-of-flight sensor in the first configuration, first emitted light at the first modulation frequency;
• determining, based at least in part on first return light associated with the first emitted light and received at the time-of-flight sensor, first time-of-flight sensor information associated with the first configuration, the first time-of-flight sensor information including first depth information;
• determining an estimated distance of a surface based on the first depth information, the estimated distance not exceeding a first nominal maximum depth associated with the first configuration;
• causing the time-of-flight sensor to be configured in a second configuration, the second configuration having an associated second modulation frequency higher than the first modulation frequency;
• causing the time-of-flight sensor to emit, with the time-of-flight sensor in the second configuration, second emitted light at the second modulation frequency;
• determining, based at least in part on second return light associated with the first emitted light and received at the time-of-flight sensor, second time-of-flight sensor information determined in the second configuration, the second time-of-flight sensor information including second depth information and the second configuration having an associated second nominal maximum depth different from the first nominal maximum depth;
• and
• determining, based at least in part on the second depth information and the estimated distance, a measured depth of the surface, the measured depth corresponding to a candidate depth of a plurality of candidate depths, the plurality of candidate depths comprising a nominal depth not exceeding a second nominal maximum depth of the time-of-flight sensor associated with the second configuration and a first candidate depth comprising a sum of the nominal depth and the second nominal maximum depth.