Optical designs using cylindrical lenses for improved resolution in lidar systems

A lidar system for three-dimensional imaging, the lidar system comprising:

• a laser source configured to emit a plurality of laser pulses, the laser source having an emission area that has a first width in a first direction and a first height in a second direction orthogonal to the first direction, the first width being greater than the first height;
• a cylindrical lens having a negative power and positioned in front of the laser source, the cylindrical lens being oriented such that a power axis of the cylindrical lens is substantially along the first direction, the cylindrical lens configured to transform the emission area into a virtual emission area having a virtual width and a virtual height, the virtual width being less than the first width;
• an emission lens positioned downstream from the cylindrical lens, the emission lens being rotationally symmetric and configured to collimate and direct the plurality of laser pulses towards one or more objects, the one or more objects reflecting the plurality of laser pulses to generate a plurality of return laser pulses;
• a receiving lens being rotationally symmetric and configured to receive and focus each of the plurality of return laser pulses to a return beam spot at a focal plane of the receiving lens;
• a detector having a detection surface positioned at the focal plane of the receiving lens and configured to receive and detect each of the plurality of return laser pulses;
• and
• a processor coupled to the laser source and the detector, the processor configured to:
• determine a time of flight for each of the plurality of return laser pulses;
• and
• construct a three-dimensional image of the one or more objects based on the determined time of flight for each of the plurality of return laser pulses.

A method of three-dimensional imaging, the method comprising:

• translating a laser source and a cylindrical lens in unison, the laser source having an emission area with a first height and a first width greater than the first height, the cylindrical lens having a negative power and positioned in front of the laser source, the cylindrical lens being oriented such that a power axis of the cylindrical lens is substantially in a width direction, wherein the laser source is translated to each of a plurality of emission locations in an emission plane;
• emitting, using the laser source, a plurality of laser pulses, each of the plurality of laser pulses being emitted at a respective one of the plurality of emission locations;
• collimating and directing, using an emission lens, the plurality of laser pulses towards one or more objects, the one or more objects reflecting each of the plurality of laser pulses to generate a plurality of return laser pulses;
• receiving and focusing, using a receiving lens, each of the plurality of return laser pulses to a plurality of corresponding detection locations in a detection plane, each corresponding detection location being conjugate with a respective emission location;
• translating a detector to each of the plurality of corresponding detection locations in the detection plane;
• detecting, using the detector, each respective return laser pulse of the plurality of return laser pulses at each respective detection location of the plurality of detection locations;
• determining, using a processor, a time of flight for each of the plurality of return laser pulses;
• and
• constructing, using the processor, a three-dimensional image of the one or more objects based on the time of flight for each of the plurality of return laser pulses.