Active Imaging System with Deflected Pulsed Beam for Large Field

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Solution Overview

Problem

Current active imaging systems face limitations in achieving high signal-to-noise ratio, spatial resolution, and insensitivity to motion blur, especially in degraded atmospheric conditions, and are restricted in simultaneously imaging objects separated by large angular or depth distances.

Innovation Solution

The method involves emitting a pulsed incident beam that is backscattered by a portion of the observed zone, forming a backscatter spot on the photosensitive surface, with pulses deflected onto respective portions of the zone, and acquiring thumbnails from these backscatter spots, allowing for increased useful illuminated surface and improved performance criteria without excessive data processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple objects separated by large angular or depth distances are simultaneously imaged, then the field of view coverage is improved, but the spatial resolution and signal-to-noise ratio deteriorate

Engineering Contradiction:
Improvefield of view coverageVSAvoidspatial resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The observed zone is divided into multiple sub-zones, with each sub-zone imaged separately by deflecting the incident beam to different portions of the zone. Thumbnails from each sub-zone are acquired and combined to form the complete image, allowing high spatial resolution to be maintained while covering a large overall field of view

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from imaging the entire field of view simultaneously to imaging different sub-zones at different time instances. This temporal dimension allows the incident beam to be sequentially directed to different spatial locations, achieving both large field coverage and high spatial resolution

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

2Area of stationary object

If the incident beam illuminates the entire observed zone at each pulse, then the field of view coverage is improved, but the signal-to-noise ratio and spatial resolution deteriorate

Engineering Contradiction:
Improveuseful illuminated surfaceVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

Instead of uniformly illuminating the entire observed zone, the incident beam is concentrated on specific sub-zones at each pulse. This local illumination approach increases the light intensity and signal-to-noise ratio for each sub-zone while the deflection mechanism ensures complete coverage of the entire field of view over time

Inventive Principle:
Principle #3Local quality

3Measurement precision

If digital accumulation of images from multiple pulses is used, then the signal-to-noise ratio is improved, but the data processing rate and effective exposure time increase excessively

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoiddata processing rate
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The observed zone is segmented into sub-zones that are illuminated and imaged separately. This segmentation allows the system to acquire complete images of each sub-zone in fewer pulses, reducing the total number of pulses needed and thereby decreasing data processing requirements while maintaining signal-to-noise ratio

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of requiring full digital accumulation from many pulses across the entire field of view, the system uses partial illumination of sub-zones with sufficient light intensity to achieve adequate signal-to-noise ratio in fewer pulses, reducing excessive data processing needs

Inventive Principle:
Principle #16Partial or excessive 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 enhances the signal-to-noise ratio and spatial resolution, reduces blurring effects, and enables simultaneous imaging of objects separated by larger distances, while maintaining reasonable data processing throughput and ocular safety.

Implementation Method 1

a pulsed incident light beam source which illuminates the observed area with each pulse of the incident beam

Methodology Applied
Scientific EffectLight emission: Laser

Implementation Method 2

a backscattering of a pulse of the incident beam only by a portion of the observed zone, forming a backscatter spot on the photosensitive surface

Methodology Applied
Scientific EffectBackscattering: Scattering

Implementation Method 3

a deflection means for deflecting pulses of the incident beam onto respective portions of the observed zone

Methodology Applied
Scientific EffectBeam deflection: Reflection

Implementation Method 4

an optronic sensor having a photosensitive face with a field of vision capable of substantially covering the observed area

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentEP2420052B1Method and system for active imaging with a large field
Publication Date: 2015.12.02 ONERA OFFICE NAT DETUD & DE RECH A
  • EP2420052B1 patent drawingFigure 1
  • EP2420052B1 patent drawingFigure 2~5
  • EP2420052B1 patent drawingFigure 6~10

AI summary

According to the invention, the imaging system contains an impulsion light source (1) for an input light beam (FI) oriented toward an observed area (ZO) and an optoelectronic sensor (3) having a photosensitive surface (31) with a visibility capable of substantially covering the observed area. An impulsion of the incident light beam is backscattered by only by a portion (PZO) of the observed area into a backscattered spot (TR) on the photosensitive surface (31). A deflection device (2) deflects the impulsions of the incident light beam onto the respective portions of the observed area. A device (4) acquires thumbnail images corresponding to the backscattered spots resulting in impulsions of the incident light beam. The system combines said thumbnail images to produce an image having a sufficiently high signal-to-noise ratio for portions of interest of the observed area, a high spatial resolution, and a greater insensitivity to motion blurs.