OCT Image Coordinate Correction for Accurate Intraocular Measurement
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Solution Overview
Problem
Conventional OCT imaging methods transform the contour shape of tomographic images into rectangles, leading to significant differences between the shape in the image and the actual shape, especially with wider angles of view, and result in errors when measuring intraocular distances based on pixel multiplication.
Innovation Solution
The ophthalmologic information processing apparatus corrects OCT images by specifying a transformation position based on optical characteristics of the eye, transforming pixel positions into actual scan positions using a predetermined coordinate system, allowing for accurate representation of the actual shape and morphology of intraocular sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the contour shape of the acquired tomographic image is transformed into a rectangle, then the image processing becomes simpler, but the difference between the shape of the predetermined site in the tomographic image and the actual shape increases
Solution Approach 1:
The patent transforms the rectangular image coordinates into a polar coordinate system that reflects the actual radial scan geometry. This dimensional transformation allows the image to represent the true shape of intraocular sites by mapping pixel positions according to their actual spatial relationships in the eye, rather than maintaining a simplified rectangular projection.
2Ease of operation
If the intraocular distance is obtained by multiplying the number of pixels between two points by the pixel size, then the measurement process becomes straightforward, but the error in the intraocular distance increases depending on the depth position
Solution Approach 1:
The patent changes the coordinate parameters from uniform rectangular grid coordinates to polar coordinates that account for radial scan geometry and depth variations. This parameter transformation allows distance measurements to be calculated based on actual spatial relationships rather than simple pixel multiplication, thereby improving accuracy across different depth positions while maintaining computational feasibility.
Data Source
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AI summary
This ophthalmic information processing device corrects an image of a subject eye that is formed by arranging a plurality of A scan images obtained by scanning the inside of the subject eye with measuring light deflected about a scan center position. The ophthalmic information processing device includes an identifying unit and a conversion unit. The identifying unit identifies a conversion position which corresponds to a pixel position in the image of the subject eye and follows a direction of travel of the measuring light that passes through the scan center position. The conversion unit converts the pixel position into the conversion position identified by the identifying unit.