Speckle Pattern Imaging for Long-Range 3D Reconstruction
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Solution Overview
Problem
Current three-dimensional imaging technologies face limitations in long-range scanning accuracy, resolution, and computational complexity, particularly when dealing with opaque surfaces and situations where reference points cannot be predetermined or implemented, such as in speckle-pattern sampling methods.
Innovation Solution
The system employs a coherent radiation source emitting multiple wavelengths to create speckle patterns, with a processor constructing autocorrelations from intensity measurements to reconstruct object representations using a projected reference point and regional image selection techniques, reducing sensitivity to atmospheric turbulence and coherence requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If triangulation-based laser scanners are used for long-range scanning, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent replaces mechanical triangulation scanning systems with a speckle-pattern-based optical sensing system. Instead of using complex mechanical scanners with moving mirrors and precise angular measurements, the invention uses coherent radiation to create speckle patterns that encode three-dimensional information, which are then decoded through autocorrelation analysis. This substitution of mechanical systems with optical-field-based methods resolves the contradiction by achieving high measurement precision without requiring large, complex scanner mechanisms.
Solution Approach 2:
The patent changes the fundamental measurement parameter from angular position (in triangulation) to speckle pattern intensity distribution across multiple wavelengths. By measuring how speckle patterns vary with wavelength and position, the system can reconstruct three-dimensional information without requiring precise mechanical angular measurements, thereby reducing device complexity while maintaining measurement precision.
2Ease of operation
If speckle-pattern sampling is used without reference points, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent implements a self-service mechanism where the system automatically generates its own reference points through projected reference patterns. These reference points are superimposed on the object's speckle pattern, enabling the system to self-calibrate and determine range information without requiring external reference objects or manual setup. This resolves the contradiction by maintaining ease of operation (no external references needed) while improving measurement precision through automated reference generation.
Solution Approach 2:
The patent performs preliminary action by pre-projecting reference patterns onto the object before actual measurement. These reference patterns create known reference points in the speckle field that are used to calibrate the measurement system and establish range references. By preparing these references in advance, the system achieves both operational simplicity (automatic calibration) and measurement precision (known reference points for comparison).
3Speed
If conventional laser radars are used for long-range imaging, then speed is improved, but measurement precision deteriorates
Solution Approach 1:
The patent uses periodic action by rapidly tuning the laser wavelength across multiple frequencies in a systematic sequence. Instead of using continuous-wave lasers at fixed wavelengths, the system periodically modulates the wavelength and captures speckle patterns at each wavelength step. This periodic wavelength modulation enables the system to achieve both fast imaging (through rapid sequential measurement) and high precision (through wavelength-dependent speckle analysis that provides range information).
Solution Approach 2:
The patent adds another dimension to the measurement by incorporating wavelength as a third variable alongside spatial position and time. Conventional laser radars measure only spatial and temporal information, but this system measures speckle patterns as a function of wavelength, position, and time. By analyzing how speckle patterns evolve with wavelength changes, the system extracts range information with high precision while maintaining fast imaging speeds through efficient multi-wavelength sampling.
4Measurement precision
If large optics are used to achieve high lateral resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces large optical systems with computational methods. Instead of using large lenses and mirrors to achieve high lateral resolution through optical focusing, the system uses speckle pattern analysis and autocorrelation techniques to extract spatial information computationally. The coherent radiation creates speckle patterns that encode spatial information, which is then decoded through signal processing rather than optical magnification, thereby achieving high lateral resolution without large optics.
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 enables high lateral resolution and range resolution without large optics or rigid sensors, is insensitive to turbulence, and can reconstruct object shapes efficiently across a broad range of applications, including biometrics and long-range metrology.
Implementation Method 1
speckle is an interference phenomenon that occurs when coherent radiation (e.g., laser light) is reflected from a rough or multiply scattering sample onto a detection plane
Implementation Method 2
Due to scattering of photons from and within the sample, different photons travel different distances to the detection plane
Implementation Method 3
The FT process yields the three-dimensional autocorrelation function of the three-dimensional image of the object
Data Source
AI summary
Disclosed are systems and methods to extract information about the size and shape of an object by observing variations of the radiation pattern caused by illuminating the object with coherent radiation sources and changing the wavelengths of the source. Sensing and image-reconstruction systems and methods are described for recovering the image of an object utilizing projected and transparent reference points and radiation sources such as tunable lasers. Sensing and image-reconstruction systems and methods are also described for rapid sensing of such radiation patterns. A computational system and method is also described for sensing and reconstructing the image from its autocorrelation. This computational approach uses the fact that the autocorrelation is the weighted sum of shifted copies of an image, where the shifts are obtained by sequentially placing each individual scattering cell of the object at the origin of the autocorrelation space.