Corneal topography slit image alignment via analysis of half-slit image alignment

1. A corneal topography slit image alignment system comprising;

a half-slit projector for projecting half-slit images onto a patient's eye, wherein the half-slit images are to be aligned into a single slit image;

a camera for capturing an image of the aligned slit image;

a computer processor, including memory, connected to the half-slit projector and the camera for analyzing the alignment of half-slit images; and

an edge detector for detecting edges of each captured half-slit image and determining an amount of misalignment of the half slit images relative to the half-slit images aligned into a single slit image thereby allowing corrections of slit images obtained by a slit beam system.

2. The invention of claim 1 , wherein each half-slit image includes at least two opposing side edges and an end edge and wherein each half-slit generally forms half of a single slit when aligned such that each end edge abuts the other end edge.

3. The invention of claim 2 , wherein a vertical gap between the end edges corresponds to a misalignment in a distance from the camera of the slit beam system.

4. The invention of claim 2 , wherein a horizontal separation between the side edges of each half-slit image correspond to a horizontal misalignment of slit images obtained from the slit beam system.

5. The invention of claim 2 , wherein a vertical misalignment of a mean of a vertical position of the end edges from an image center corresponds to a vertical misalignment of the slit image obtained from the slit beam system.

6. A method of determining an amount of misalignment of a pair of half-slit images of a corneal topography slit image system, the method comprising to steps of;

projecting, with a half-slit projector, a pair of half-slit images onto a patient's eye, wherein the half-slit images are to be aligned into a single slit image;

capturing, with a camera an image of the aligned half-slit images;

analyzing, with a computer processor, including a memory connected to the half-slit projector and the camera the alignment of the half-slit images; and

detecting, with an edge detector, edges of each captured half-slit image and determining an amount of misalignment of the half-slit images relative to the half-slit images aligned into a single slit image thereby allowing a correction of slit images obtained by a slit beam system.

7. The method of claim 6 , wherein the detecting step includes detecting at least two side edges and an end edge of each half-slit and wherein each half-slit generally forms half of a single slit when aligned, such that each end edge abuts the other end edge.

8. The method of claim 7 further including a step of determining a vertical gap distance between the end edges, wherein the vertical gap distance corresponds to a misalignment of a distance from the camera of the slit beam system.

9. The method of claim 7 further including a step of determining a horizontal separation distance between the side edges of each half-slit image, wherein the horizontal separation distance corresponds to a horizontal misalignment of slit images obtained from the slit beam system.

10. The method of claim 7 further including a step of determining a vertical misalignment distance from a mean vertical position of the end edges from an image center, wherein the vertical misalignment distance corresponds to a vertical misalignment of slit images obtained from the slit beam system.