Image Processing Apparatus Barycenter Calculation via Quadric Surface Fitting

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Solution Overview

Problem

Image processing systems face challenges in accurately calculating the barycenter of a subject region, especially when the subject is inclined or bent, leading to underestimation or overestimation of data amounts in pixels, resulting in miscalculated barycentric coordinates.

Innovation Solution

An image processing apparatus that applies weighting processing based on the amount of information projected per unit (pixel) and uses three-dimensional shape data to calculate accurate barycentric coordinates by fitting the subject into a quadric surface, correcting for pixel area and inclination, thereby ensuring accurate barycenter calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If uniform weighting is applied to all pixels in barycenter calculation, then calculation simplicity is maintained, but measurement precision deteriorates when subject is inclined

Engineering Contradiction:
Improvecalculation simplicityVSAvoidbarycenter calculation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies different weights to different pixels based on their local imaging conditions. Specifically, pixels imaging inclined subject regions are assigned higher weights to compensate for the reduced data amount per pixel, while pixels imaging non-inclined regions use standard weights. This local differentiation resolves the contradiction by maintaining calculation feasibility while improving accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the weighting parameter from uniform (all pixels weight=1.0) to variable weights based on imaging conditions. The weight for each pixel is determined by calculating the subject area projected onto that pixel, and pixels with smaller projected areas (indicating inclination) receive higher weights. This parameter transformation enables accurate barycenter calculation for inclined subjects.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If simple pixel-based statistical calculation is used, then processing speed is maintained, but measurement precision deteriorates for inclined subjects

Engineering Contradiction:
Improveprocessing speedVSAvoidbarycenter calculation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary calculation of the subject's three-dimensional shape and determines the imaging conditions (inclination angle, subject distance) before performing the barycenter calculation. This preliminary action enables the system to pre-determine appropriate weights for each pixel, allowing the main barycenter calculation to proceed efficiently with corrected weights rather than requiring complex iterative corrections during the calculation itself.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If uniform pixel weighting is applied, then device complexity is minimized, but measurement precision worsens due to underestimation of inclined region data

Engineering Contradiction:
Improvesystem complexityVSAvoiddata amount estimation accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary calculation step that determines the subject area projected onto each pixel based on three-dimensional shape data and imaging geometry. This intermediary information serves as a mediator between the simple pixel-based system and the need for accurate data amount estimation, enabling the system to calculate appropriate weights without requiring complex hardware modifications.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3168780B1Image processing apparatus, image processing method, and computer-readable recording medium
Publication Date: 2020.06.24 FUJITSU LTD
  • EP3168780B1 patent drawingFigure 1
  • EP3168780B1 patent drawingFigure 2
  • EP3168780B1 patent drawingFigure 3~4

AI summary

An image processing apparatus (1) includes an imaging unit (12) that divides an image of a subject into blocks, a quadric-surface fitting unit (15) that calculates a distance from a reference position to the subject that corresponds to each block, a weight calculating unit (15) that calculates a weight of each block according to the distance, and a barycenter calculating unit (15) that corrects information about a size of the subject projected in each block based on the weight, and calculates barycentric coordinates based on the corrected information about the size of the subject.