Anisotropic Blur Element for Digital Projector Edge Resolution

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Solution Overview

Problem

Current high contrast edge projection systems, especially those using digital projector arrays, face challenges with interpixel gaps and discretization, leading to low contrast and sharpness issues, which are exacerbated by the need for precise alignment and high costs in analogue systems.

Innovation Solution

The introduction of anisotropic blurring elements between the light source and the projection in digital projector arrays, which blur pixels in directions of equal or greater illumination, reducing interpixel gaps and discretization without impairing contrast, by aligning the blurring map with the projector and selectively blurring pixels tangentially along edge contours.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If digital projector arrays are used to project high contrast edges, then cost and complexity are reduced, but interpixel gaps and discretization cause loss of resolution and contrast

Engineering Contradiction:
Improveprojector system complexityVSAvoidedge resolution
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A diffuser element is introduced as an intermediary component between the digital projector array and the projection lens. This diffuser mediates the light from discrete pixels, creating a continuous illumination profile that eliminates interpixel gaps while preserving the digital projector's low cost and complexity advantages. The diffuser acts as a bridge that transforms the pixellated output into smooth, high-resolution edges.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the spatial distribution parameter of light by using a diffuser to transform the discrete pixel pattern into a continuous intensity distribution. This parameter change allows the system to achieve high edge resolution without requiring higher pixel density, thereby maintaining cost-effectiveness while improving manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If conventional blurring is applied to remove interpixel gaps, then gap visibility is reduced, but edge sharpness and contrast are degraded

Engineering Contradiction:
Improveinterpixel gap visibilityVSAvoidedge sharpness
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The diffuser is positioned and configured to apply localized blurring only at the interpixel gap regions, while preserving the sharpness of the actual edge features. This selective local quality modification eliminates the harmful gap visibility without degrading the useful edge sharpness, resolving the contradiction between gap removal and edge definition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The diffuser serves as an intermediary that selectively affects different regions of the projected image. It mediates between the discrete pixel output and the desired continuous edge, applying smoothing only where needed (at gaps) while preserving edge integrity through its specific positioning and optical properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If multiple DMD projectors are used to improve coverage and resolution, then image quality is enhanced, but alignment complexity and system cost increase

Engineering Contradiction:
Improveprojected image resolutionVSAvoidalignment requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple projectors into a single digital projector array system by using a diffuser to combine the output of many individual pixels into a unified continuous image. This consolidation achieves the coverage and resolution benefits of multiple projectors while eliminating the alignment complexity, as the diffuser naturally integrates all pixel outputs without requiring precise mechanical registration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The diffuser acts as a mediating element that combines the outputs of multiple pixel elements into a seamless unified image. This intermediary approach achieves the effect of multiple projectors working together without the need for their physical presence and alignment, thereby reducing system complexity while maintaining high resolution.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If laser scanning is used to achieve high resolution patterns, then edge precision is improved, but scanning speed limits pattern formation speed and contrast

Engineering Contradiction:
Improvepattern edge precisionVSAvoidpattern formation speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical laser scanning system with a static digital projector array combined with a diffuser. This substitution eliminates the moving scanning components and their speed limitations, allowing parallel projection of entire patterns at high speed while maintaining edge precision through the diffuser-mediated continuous illumination.

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

Solution Approach 2:

The diffuser enables continuous illumination across the entire projection area simultaneously, replacing the sequential scanning action of lasers. This continuous parallel action achieves both high precision edges and high productivity, as all parts of the pattern are formed at once rather than sequentially during scanning.

Inventive Principle:
Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach effectively reduces interpixel gaps and discretization, enhancing the resolution and contrast of projected high contrast edges, allowing for higher quality images with lower cost and complexity, particularly suitable for special purpose applications like metrology and structured light projection.

Implementation Method 1

providing an anisotropically blurring optical element between an illumination source and the projection that blurs each pixel of a connected set of pixels of the illumination pattern more in directions of pixels of equal or greater illumination, and less in directions of pixels of lower illumination

Methodology Applied
Scientific EffectAnisotropic blurring: Diffusion

Data Source

PatentEP2710427B1High resolution high contrast edge projection
Publication Date: 2016.06.22 NAT RES COUNCIL OF CANADA
  • EP2710427B1 patent drawingFigure 1
  • EP2710427B1 patent drawingFigure 2
  • EP2710427B1 patent drawingFigure 3

AI summary

Generating a high definition projected illumination pattern from a substantially lower resolution digital projector array involves: selectively illuminating a connected set of pixels to produce a pixellated, high contrast edge feature, and positioning an anisotropically blurring optical element (ABOE) between a light source of the projector array and the projection. The ABOE applies an anisotropic blur pattern to pixels of the at least one connected set, to locally preferentially blur the pixel more (and preferably substantially only) in a direction of equally or more strongly illuminated pixels, and not in directions of less illuminated pixels. Preferably a contour of the connected set has no beginning or end within a periphery of the illumination plane, and has bounded curvature, permitting simple ABOEs to be used. Several images each having several or many edges can be produced using a same ABOE. The ABOE may alleviate interpixel gap effects for non-edge pixels too.