CNN Image Stitching for Small-Overlap X-Ray Imaging

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing image stitching methods in X-ray imaging face challenges with inaccurate stitching results and failures due to local maxima or minima in similarity measures, leading to increased patient dose and unreliable stitching processes, especially for large or elongated anatomical structures.

Innovation Solution

A convolutional neural network (CNN) is trained to determine optimal displacement for image stitching by optimizing its parameters and penalizing deviations from a reference cost function, allowing seamless image combination with reduced overlapping areas and patient dose.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If large overlapping areas are used in image stitching, then the stitching reliability is improved, but the patient dose increases

Engineering Contradiction:
Improvestitching reliabilityVSAvoidpatient dose
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by training a convolutional neural network in advance to recognize and predict displacement patterns in overlapping image areas. The pre-trained CNN model can accurately determine the correct displacement between adjacent X-ray images even with minimal overlap, eliminating the need for large overlapping areas that would otherwise be required to ensure stitching reliability. This preliminary training enables the system to achieve reliable stitching results with reduced patient dose.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If small overlapping areas are used in image stitching, then the patient dose is reduced, but the stitching reliability deteriorates

Engineering Contradiction:
Improvepatient doseVSAvoidstitching reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies parameter changes by transforming the traditional approach of relying on large overlapping areas into a parameter-based solution using a trained CNN model. The system changes from using spatial overlap extent as the key parameter for reliability to using learned displacement parameters from the neural network. This parameter transformation allows accurate displacement determination even with minimal overlapping areas, maintaining stitching reliability while reducing patient dose.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If similarity measures are used for displacement estimation, then the stitching process is simplified, but the accuracy deteriorates due to local maxima or minima

Engineering Contradiction:
Improvestitching process complexityVSAvoiddisplacement estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies mechanics substitution by replacing the traditional mechanical/optical similarity measure approach with a neural network-based system. Instead of using mathematical similarity computations that are prone to local maxima and minima, the system uses a CNN model that has learned displacement patterns from training data. This substitution maintains computational efficiency while dramatically improving displacement estimation accuracy by avoiding the local extrema problems inherent in similarity-based methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4487288B1Training method, device and image represenstation system for image stitching
Publication Date: 2025.10.22 KONINKLIJKE PHILIPS NV
  • EP4487288B1 patent drawingFigure 1~2
  • EP4487288B1 patent drawingFigure 3

AI summary

The invention concerns an image processing system configured for carrying out a computer-implemented method for generating a stitched image with a convolutional neural network (208), a computer-implemented method for generating a stitched image with a convolutional neural network, and a method of training a convolutional neural network, for determining an image representation for image stitching. The training of the convolutional neural network comprises receiving image data, wherein the image data comprises at least two images (101, 102), overlapping each other in an overlapping area (103, 203) in which the images overlapping each other in a target anatomy (104), and wherein the overlapping area comprises an optimum displacement between the two images such that the two images can be correctly combined for image stitching, determining a cost function (105, 205) of the displacement of the two images in the overlapping area, determining a deviation of the cost function from a reference cost function, and optimizing the CNN based on the deviation.