Pixel Super-Resolution via Subpixel Shift in Laser Scanning
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Solution Overview
Problem
High-speed laser scanning imaging systems face challenges in achieving high pixel resolution at lower sampling rates, leading to image aliasing and artifacts, especially when the sampling clock is unlocked from the laser pulse repetition rate, which is not efficiently addressed by existing pixel super-resolution techniques that require additional hardware or complex algorithms.
Innovation Solution
A passive pixel super-resolution technique that harnesses the natural subpixel shift generated by the mismatch between laser-scan repetition frequency and digitizer sampling frequency, allowing for enhanced pixel resolution without active synchronized control or additional hardware, using image warp registration and interleaving of line scans to restore high-resolution images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed laser scanning imaging is performed at lower sampling rates, then productivity is improved, but measurement precision deteriorates due to image aliasing and loss of pixel resolution
Solution Approach 1:
The patent segments the imaging process into multiple passes, where each pass captures line scans at a lower sampling rate. By dividing the high-resolution capture into multiple sequential acquisitions with subpixel shifts, the system achieves high effective resolution without requiring the digitizer to operate at its maximum sampling rate during each individual pass, thus improving productivity while maintaining measurement precision.
Solution Approach 2:
The patent introduces a temporal dimension to the spatial sampling problem. By capturing multiple line scans at different subpixel positions over time and combining them through image warp registration, the system effectively adds a time dimension to overcome the limitations of spatial sampling at low rates, restoring pixel resolution without compromising imaging speed.
2Measurement precision
If pixel super-resolution techniques are applied to restore high-resolution images from low sampling rate data, then measurement precision is improved, but device complexity increases due to additional hardware requirements
Solution Approach 1:
The patent makes the imaging system self-servicing by utilizing the natural subpixel shifts that occur due to the inherent mismatch between the laser scan repetition frequency and the digitizer sampling frequency. This eliminates the need for external hardware mechanisms (such as piezoelectric actuators or mechanical stage movements) to intentionally create subpixel shifts, as the system automatically generates the necessary conditions through its normal operation.
Solution Approach 2:
The patent converts the harmful effect of frequency mismatch (which causes unwanted image artifacts and misalignment) into a beneficial feature. By deliberately harnessing the subpixel shifts generated by the frequency mismatch between laser scanning and digitizer sampling, the system transforms what was previously a source of error into the mechanism that enables super-resolution image reconstruction.
3Measurement precision
If active synchronized control of illumination or detection is implemented for precise subpixel shift operation, then measurement precision is improved, but device complexity and ease of operation worsen due to additional control systems
Solution Approach 1:
The system automatically generates and utilizes subpixel shifts through the natural frequency relationship between the laser scanner and digitizer, eliminating the need for external control systems to actively adjust illumination or detection positions. The subpixel shifts occur spontaneously as part of the normal imaging operation.
Solution Approach 2:
Instead of actively controlling the illumination or detection to achieve subpixel shifts (as in conventional approaches), the patent inverts the approach by allowing the subpixel shifts to occur naturally and then compensating for them through image processing. This passive approach simplifies the hardware control while achieving the same measurement precision.
4Measurement precision
If conventional pixel-SR techniques requiring additional hardware are used, then pixel resolution is improved, but ease of manufacture and device complexity worsen
Solution Approach 1:
The imaging system utilizes its own inherent frequency characteristics to generate the subpixel shifts needed for super-resolution, eliminating the need for additional hardware components that would complicate manufacturing. The system serves its own need for precise subpixel positioning through its operational parameters.
Solution Approach 2:
The patent makes the imaging system multi-functional by enabling it to simultaneously perform normal high-speed imaging and generate the subpixel-shifted data needed for super-resolution reconstruction using the same hardware components. This eliminates the need for separate dedicated hardware for subpixel shifting, simplifying manufacturing while maintaining pixel resolution improvement capabilities.
Data Source
AI summary
This invention describes a technique to enhance pixel resolution of high-speed laser scanning imaging by the means of sub-pixel sampling, applicable to one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) imaging.