Wide-Area Angiogram Synthesis via Feature Point Alignment

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Solution Overview

Problem

Conventional OCTA can only perform imaging for a relatively narrow area of the eye fundus, limiting the construction of angiograms over a wide area.

Innovation Solution

An ophthalmological device equipped with a memory to store angiograms, processors for detecting and identifying feature points, transforming angiograms based on feature point groups, and composing transformed angiograms to cover a wider area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If conventional OCTA imaging is used, then imaging can be performed with current technology, but the imaging area is limited to a relatively narrow area

Engineering Contradiction:
Improveimaging areaVSAvoidsystem complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent divides the wide-area fundus imaging task into multiple narrow-area OCTA images that are captured separately and then synthesized through image processing. The fundus is imaged in multiple regions, each with its own angiogram, and these are subsequently combined to form a comprehensive wide-area angiogram.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from two-dimensional narrow-area imaging to wide-area imaging by introducing spatial synthesis through coordinate transformation and image composition. Multiple 2D angiograms are transformed and combined in a coordinate system to create a comprehensive wide-area view, effectively expanding the imaging coverage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If multiple angiograms are captured to cover wide area, then imaging coverage is improved, but position matching and composition complexity increases

Engineering Contradiction:
Improveangiogram coverage areaVSAvoidimage processing complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent introduces feature points as intermediary elements that facilitate the matching and alignment of multiple angiograms. These feature points serve as reference markers that enable automatic position matching between different captured images, simplifying the composition process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies coordinate transformation to change the spatial parameters of individual angiograms, transforming them into a unified coordinate system. This parameter transformation enables seamless composition of multiple images while maintaining accurate spatial relationships.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If feature point matching is performed for position alignment, then imaging precision is improved, but processing time increases

Engineering Contradiction:
Improveposition matching precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs feature point detection and grouping as preliminary actions before the actual image composition. By pre-identifying and organizing feature points into groups that correspond to the same fundus locations, the system prepares the data structure needed for efficient position matching and reduces processing time during composition.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3643221B1Ophthalmological device, ophthalmological image processing method, program, and storage medium
Publication Date: 2025.04.09 TOPCON CORPORATION
  • EP3643221B1 patent drawingFigure 1
  • EP3643221B1 patent drawingFigure 2
  • EP3643221B1 patent drawingFigure 3

AI summary

An ophthalmological device in an embodiment comprises a storage unit, a detection unit, a specification unit, a deformation unit and a compositing unit. The storage unit stores a plurality of angiograms obtained by applying optical coherence tomography to the fundus of an eye being examined. The detection unit detects feature points from each of the plurality of angiograms. The specification unit specifies a plurality of feature points groups, each of said groups corresponding to the same site on the fundus, from the plurality of feature points detected by the detection unit from among the plurality of angiograms. The deformation unit deforms at least some of the plurality of angiograms on the basis of the plurality of feature point groups specified by the specification unit. The compositing unit combines two or more angiograms from among the plurality of angiograms, at least some of which were deformed by the deformation unit, on the basis of the plurality of feature point groups.