Reducing noise in images acquired with a scanning beam device

An apparatus comprising:

• an interface to allow a scanning beam device to be coupled;
• a light source optically coupled with the interface to provide light to the scanning beam device through the interface;
• an actuator driver electrically coupled with the interface to provide actuator drive signals to the scanning beam device through the interface, wherein the actuator drive signals are operable to cause the scanning beam device to scan a beam of the light over a surface in a scan with a variable velocity;
• a noise-reduction unit to generate reduced-noise representations of groups of light detected at different points in time during the scan, wherein the noise-reduction unit is to generate reduced-noise representations of groups having a plurality of different sizes, wherein the noise-reduction unit includes a variable cutoff frequency filter having a variable cutoff frequency, and wherein the noise-reduction unit is to generate the reduced-noise representations by filtering the detected light within each group with the variable cutoff frequency filter by varying the cutoff frequency for the plurality of groups having the plurality of the different sizes;
• and
• an image generation unit to generate an image of the surface by representing different positions in the image with reduced-noise representations of corresponding groups.

A method comprising:

• scanning a beam of light over a surface in a scan with a variable velocity;
• detecting light from the surface at different points in time during the scan at a substantially constant rate;
• averaging each of a plurality of different sized groups of the detected light that each correspond to a different position in an image of the surface, wherein said averaging each of the different sized groups comprises averaging only a subset of the detected light for a group that corresponds to a position in the image;
• and
• generating the image of the surface by representing each different position in the image with the average of the corresponding group.

A method comprising:

• scanning a beam of light over a surface in a scan with a variable velocity;
• detecting light from the surface at different points in time during the scan at a substantially constant rate;
• filtering the detected light including reducing frequencies above a cutoff frequency;
• varying the cutoff frequency, wherein the cutoff frequency is varied across an image of the surface based at least in part on a number of points of detected light corresponding to a given position in the image of the surface;
• and
• generating the image of the surface by representing different positions in the image with the corresponding filtered detected light.

A method comprising:

• scanning a beam of light over a surface in a spiral scan with a variable velocity, wherein the velocity increases with increasing distance from a center of the spiral scan;
• detecting light backscattered from the surface at different points in time during the scan;
• generating reduced-noise representations of groups of the detected light that each correspond to a different position in an image of the surface by filtering the groups with a variable cutoff filter, wherein sizes of the groups decreases with increasing distance from the center of the spiral scan, wherein the cutoff of the filter increases with increasing distance from the center of the spiral scan, and wherein an amount of noise reduction decreases with increasing distance from the center of the spiral scan;
• and
• generating the image of the surface by representing the different positions in the image with the reduced-noise representations of the corresponding groups.