Barycentric Projection for Color Space Interpolation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing color conversion systems face inefficiencies in handling geometrically complex Look-Up Tables (LUTs) due to limitations in interpolation methods, such as Sequential Linear Interpolation (SLI), which fail to preserve symmetries, are not compatible with all geometrical configurations, and struggle with 'gap interpolation' between incompatible grids.

Innovation Solution

The implementation of a 'barycentric projection' method within a unit hypercube, allowing for Sequential Tetrahedral Interpolation (STI), which imposes boundary conditions on facets and vertices to efficiently interpolate values, even in complex geometrical situations, by performing a series of barycentric projections and back substitutions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If Sequential Linear Interpolation (SLI) is used for color conversion, then the interpolation process is simple to implement, but it fails to preserve symmetries and is not compatible with complex geometrical configurations

Engineering Contradiction:
ImproveEase of implementationVSAvoidCompatibility with geometrical configurations
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent segments the color space into multiple simplices (tetrahedra in 3D) that form a triangulated mesh. Each simplex is processed independently using linear interpolation, while the overall structure handles complex geometries. This segmentation allows the method to maintain simplicity within each cell while achieving versatility across the entire color space, resolving the contradiction between ease of implementation and geometrical compatibility.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If traditional interpolation methods are used on adaptive rectangular grids, then storage efficiency is improved by reducing sampling rate, but interpolation accuracy deteriorates in regions with incompatible grids

Engineering Contradiction:
ImproveStorage efficiencyVSAvoidInterpolation accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent transitions from processing data in the original dimensional space to embedding it in a barycentric coordinate system. By representing points as convex combinations of simplex vertices and using barycentric coordinates for interpolation, the method accurately handles points in regions between incompatible grids. This dimensional transformation maintains storage efficiency while recovering interpolation accuracy in previously problematic regions.

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

3Device complexity

If SLI is applied to reduce dimensionality step-by-step, then computational complexity is reduced, but the method cannot handle gap interpolation between incompatible grids

Engineering Contradiction:
ImproveComputational complexityVSAvoidAbility to handle gap interpolation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces barycentric coordinates as an intermediary representation between the input color value and the interpolation result. By expressing the input point in barycentric coordinates relative to the containing simplex and using these coordinates to weight the vertex values, the method seamlessly handles gap regions between incompatible grids. This intermediary approach maintains computational efficiency while enabling versatile handling of all geometrical configurations including gap interpolation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS7423791B2Color conversion using barycentric projections
Publication Date: 2008.09.09 CANON KK
  • US7423791B2 patent drawing
  • US7423791B2 patent drawing
  • US7423791B2 patent drawing

AI summary

A method and apparatus for interpolating values for a color space from an input color value. A unit hypercube enclosing the input value is generated based on values from a look up table. A set of boundary conditions are then imposed on the unit hypercube. To perform the actual interpolation, an initial barycentric projection is performed from a selected vertex of the unit hypercube through the input value onto a boundary of the unit hypercube. If the projection satisfies one of the boundary conditions, an interpolated value is calculated using the projection by back substitution. If the initial projection does not satisfy a boundary condition, an intermediate value is generated from the previous projection and successive barycentric projections are performed using respectively different vertices of the unit hypercube through intermediate values onto a boundary of the unit hypercube until a projection satisfies one of the boundary conditions.