Image based correction of distortion from a scanner

1. An imaging system for imaging an eye, comprising:

a scanner, wherein the scanner positions a spot of light on the eye along a scanning path, the scanning path includes a plurality of scan lines;

a detector arranged to output raw data associated with positions along the scanning path, wherein the detector detects the spot of light reflected from the eye;

one or more processors that perform calculations comprising:

dividing the raw data into forward scan data and backward scan data;

reversing the order of the backward scan data to produce inverted backward scan data;

determining an offset value by calculating cross-correlation between the forward scan data and the inverted backward scan data; and

producing a first image of the eye that comprises the forward scan data and the inverted backward scan data, wherein the forward scan data is shifted by the offset value relative to the inverted backward scan data, and

adjusting a data sampling window based on the offset value.

2. The imaging system of claim 1 , wherein the eye is a fundus of the eye.

3. The imaging system of claim 1 , wherein the cross-correlation is calculated relative to shift values between the forward scan data and the inverted backward scan data, and the offset value is a shift value associated with a maximum value of the cross-correlation.

4. The imaging system of claim 1 , further comprising a light source for producing the spot of light, wherein the light source is a laser, a broadband light source, or multiple lights sources.

5. The imaging system of claim 1 , wherein the raw data is a time series of data points associated with physical positions along the scanning path.

6. The imaging system of claim 1 , wherein the forward scan data is associated with forward portions of the scanning path, the backward scan data is associated with backward portions of the scanning path, and the forward portions of the scanning path are not parallel to the backward portions of the scanning path.

7. The imaging system of claim 6 , wherein the forward portions of the scanning path include a plurality of forward scanning lines that are parallel to each other, and the backward portions of the scanning path include a plurality of backward scanning lines that are parallel to each other.

8. The imaging system of claim 1 , further comprising:

producing a second image of the eye by transforming the first image to compensate for the relative variations in the motion of the scanner.

9. The imaging system of claim 8 , wherein the scanner includes a resonant scanner, and the relative variations in the motion of the scanner refers to the substantially sinusoidal motion of the resonant scanner.

10. The imaging system of claim 8 , further comprising:

producing a third image of the eye by cropping the second image to a limited portion of the second image, wherein the limited portion of the second image is associated with portions of the scanning path in which motion of the scanner substantially linear.

11. The imaging system of claim 1 , wherein the plurality of scan lines consists of one forward scan line and one backward scan line, the first image consists of two lines, multiple first images of the eye are obtained; the multiple first images are combined into a fourth image.

12. The imaging system of claim 1 , wherein the scanner further comprises a second scanner moving in a direction substantially perpendicular to a resonant scanner.

13. The imaging system of claim 1 , further comprising forming a horizontal synchronization signal based on the offset value.

14. A method of synchronizing scan lines associated with an image of an eye, comprising:

receiving raw data associated with positions of a spot of light along a scanning path on the eye, wherein the raw data is from a detector that detects the spot of light reflected from the eye;

dividing the raw data into forward scan data and backward scan data;

reversing the order of the backward scan data to produce inverted backward scan data;

determining an offset value by calculating cross-correlation between the forward scan data and the inverted backward scan data; and

producing a first image of the eye that comprises the forward scan data and the inverted backward scan data, wherein the forward scan data is shifted by the offset value relative to the inverted backward scan data, and

adjusting a data sampling window based on the offset value.

15. A non-transitory computer readable medium encoded with instructions for:

receiving raw data associated with positions of a spot of light along a scanning path on the eye, wherein the raw data is from a detector that detects the spot of light reflected from the eye;

dividing the raw data into forward scan data and backward scan data;

reversing the order of the backward scan data to produce inverted backward scan data;

determining an offset value by calculating cross-correlation between the forward scan data and the inverted backward scan data; and

producing a first image of the eye that comprises the forward scan data and the inverted backward scan data, wherein the forward scan data is shifted by the offset value relative to the inverted backward scan data, and

adjusting a data sampling window based on the offset value.

16. The imaging system of claim 1 , wherein the first image of the eye comprises the forward scan data interlaced with the inverted backward scan data.

17. The method of claim 14 , wherein the first image of the eye comprises the forward scan data interlaced with the inverted backward scan data.

18. The non-transitory computer readable medium of claim 15 , wherein the first image of the eye comprises the forward scan data interlaced with the inverted backward scan data.