TDI Detector Array Misalignment Compensation

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Solution Overview

Problem

Time delay and integration (TDI) image scanners face misalignment issues due to variations in the relative motion of the object and the scanner, leading to suboptimal image quality and smearing effects.

Innovation Solution

A detector array with TDI detectors organized into segments, where signals are routed between columns to compensate for misalignment by passing them to adjacent columns that better align with the target object, ensuring accurate data accumulation and image correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If TDI detectors are used to accumulate multiple exposures, then integration time is increased, but misalignment between exposures occurs due to motion variations

Engineering Contradiction:

Improveintegration timeVSAvoidalignment precision

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The detector array is divided into multiple segments, with each segment containing multiple columns of detectors. This segmentation allows independent processing and realignment of signals from different spatial regions, enabling correction of misalignment between exposures while maintaining extended integration time

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system determines misalignment between actual and designed scan axes by analyzing signal positions across detector columns. This feedback information is then used to dynamically adjust signal routing between columns in subsequent segments, compensating for misalignment and maintaining image quality during extended integration

Inventive Principle:

Principle #23Feedback

2Reliability

If signal is passed to the designed next column, then data accumulation follows the designed scan axis, but misalignment causes smearing in the resulting image

Engineering Contradiction:

Improvedata accumulation accuracyVSAvoidimage quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The signal routing between detector columns is made dynamic rather than fixed. Based on detected misalignment, the system adaptively routes signals to different next columns in different segments, allowing the data accumulation path to adjust in real-time to actual motion conditions and prevent smearing

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the routing parameter (which column receives the signal) based on detected misalignment conditions. By varying the signal destination column according to actual scan axis deviation, the system maintains accurate data accumulation despite motion variations

Inventive Principle:

Principle #35Parameter changes

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 compensates for misalignment, resulting in improved image quality that better matches the target object, reducing smearing and enhancing the accuracy of the scanned image.

Implementation Method 1

A time delay and integration (TDI) image scanner accumulates multiple exposures of the same object as the object moves relative to the scanner. The scanner effectively increases the integration time for collecting incident light.

Methodology Applied

Scientific EffectTime delay and integration:

Implementation Method 2

receiving, at a detector array, electromagnetic (E-M) radiation from a target object. The detector array comprises time delay and integration (TDI) detectors

Methodology Applied

Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentUS8300276B2Compensating for misalignment in an image scanner

Publication Date: 2012.10.30 RAYTHEON CO

AI summary

In certain embodiments, compensating for misalignment comprises receiving, at a detector array, electromagnetic (E-M) radiation from a target object. The detector array comprises time delay and integration (TDI) detectors organized into segments. Each segment comprises one or more rows of detectors perpendicular to a designed scan axis, and comprises columns of detectors parallel to the designed scan axis. The detector array moves in a relative scan direction relative to the target object. The following is performed for each segment and for each column of each segment. If there is misalignment at a segment, a signal is passed to a correcting next column of a next segment in the direction of the misalignment, where the signal accumulates scan data of a portion of the target object. Otherwise, the signal is passed to a designed next column of the next segment in the direction of the designed scan axis.