Bi-directional scanning and imaging with scanning compensation

A method for bi-directional imaging comprising:

• providing a light beam;
• scanning the light beam through a scan path in a forward direction and a reverse direction;
• sensing the position of the light beam and generating first and second position signals corresponding to first and second positions in the scan path;
• determining first and second scan durations based on the first and second position signals, the first and second scan durations being time periods corresponding to the first and second sensor position signals, respectively;
• producing first and second control signals corresponding to the first and second scan durations;
• generating first and second drive signals from the first and second control signals;
• driving, based on the fist and second control signals, the light beam in the forward direction with a forward drive force and in the reverse direction with a reverse drive force to produce the scanning of the light beam;
• adjusting the forward and reverse drive forces based on the first and second scan durations to substantially equalize the first and second scan durations.

A bi-directional imaging apparatus for operating on an incoming image signal comprising:

• a light source for generating a light beam;
• a scanner for scanning the light beam through a scan path in a forward direction and a reverse direction;
• first and second sensors disposed in the scan path for sensing the light beam as it scans across the sensors to produce first and second sensor signals corresponding respectively to the light beam scanning across the first and second sensors;
• control logic for receiving the first and second sensor signals and determining first and second rasterization rates based on the first and second sensor signals, and producing first and second control signals corresponding to the first and second rasterization rates;
• first and second clocks for producing first and second clock signals having first and second frequencies, respectively, corresponding to the first and second control signals, respectively;
• an image rasterization logic block receiving the first and second clock signals and the incoming image signal and for rasterizing the incoming image signal based on the first and second clock signals to produce a rasterized signal,
• a modulator receiving the rasterized signal and modulating the light beam based on the rasterized signal.

A method for bi-directional imaging based on an incoming image signal comprising:

• providing a light beam;
• scanning the light beam through a scan path in a forward direction and a reverse direction;
• sensing the position of the light beam and generating first and second position signals corresponding to first and second positions in the scan path;
• determining first and second rasterization rates based the first and second position signals;
• producing a rasterized signal based on the first and second rasterization rates, the first and second position signals and the incoming image signal;
• and
• modulating the light beam based on the rasterized signal, whereby the first and second rasterization rates compensate for differences in the durations of scans in the forward and reverse directions to provide scan to scan alignment of the modulation of the light beam.