On-Chip Per-Pixel Pseudo-Random Modulation for Transient Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional focal plane arrays (FPAs) face challenges in simultaneously achieving high spatial resolution and fast frame rates for transient target imaging, leading to streaked images and degraded spatial information, especially in wide-area surveillance applications.
Innovation Solution
The implementation of on-chip per-pixel space-time modulation in a digital focal plane array (DFPA) architecture, using a per-pixel shutter and pseudorandom modulation to enable multi-target and multi-frequency discrimination, allowing for temporal super-resolution and reducing temporal blurring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional FPAs use analog readout with external ADCs, then device complexity is reduced, but measurement precision and temporal resolution deteriorate due to inability to perform per-pixel temporal modulation
Solution Approach 1:
The patent divides the focal plane array into independently functional pixels, each containing its own ADC and modulation circuitry. This segmentation enables per-pixel temporal modulation and high-speed sampling without requiring complex external processing, resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
Each pixel is equipped with self-contained circuitry including ADCs and pseudo-random modulation generators, allowing pixels to perform temporal modulation and signal conversion independently. This self-service approach eliminates the need for complex external processing while maintaining high temporal resolution
2Speed
If COTS FPA detectors increase frame rate, then speed of transient target capture improves, but spatial resolution deteriorates due to streaking effects
Solution Approach 1:
The patent employs periodic pseudo-random modulation at high frequencies within each pixel, allowing temporal sampling at rates much higher than the readout frame rate. This periodic action captures transient targets without streaking while maintaining spatial resolution, resolving the contradiction between speed and measurement precision
Solution Approach 2:
The system changes the temporal sampling parameter by using pseudo-random modulation sequences that operate at frequencies远高于 the readout rate. This parameter change enables high-speed transient capture to be encoded into lower-rate readout data, eliminating streaking while preserving both speed and spatial resolution
3Measurement precision
If DFPA uses on-chip global capability for single transient-feature extraction, then measurement precision for single target improves, but adaptability for multi-target and multi-frequency discrimination deteriorates
Solution Approach 1:
Each pixel is equipped with universal pseudo-random modulation circuitry that can be independently configured for different modulation sequences. This multi-functionality allows the same hardware to discriminate multiple targets and frequencies simultaneously, resolving the contradiction between measurement precision and adaptability
Solution Approach 2:
The patent applies different pseudo-random modulation sequences to different pixels or pixel groups, creating local variations in modulation characteristics. This local quality approach enables multi-target and multi-frequency discrimination while each pixel maintains high measurement precision for its assigned targets
4Measurement precision
If per-pixel pseudo-random modulation is implemented, then temporal super-resolution improves, but device complexity increases due to additional on-chip circuitry
Solution Approach 1:
The patent combines the ADC, digital register, and pseudo-random modulation circuitry into an integrated on-chip pixel structure. This merging eliminates the need for separate external components and complex interconnections, achieving temporal super-resolution while managing device complexity through integration
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-resolution, low-latency imaging with reduced raw data volume, supporting wide-field-of-view applications and improving transient feature extraction for both resolved and unresolved targets, while maintaining a high frame rate.
Implementation Method 1
a first photodetector to convert a first portion of light that is scattered and/or reflected from a scene into a first analog signal
Data Source
AI summary
Conventional methods for imaging transient targets are constrained by a trade-off between resolution and frame rate, and transient targets moving faster than the detector frame typically result in image blurring. Imagers using digital-pixel focal plane arrays (“DFPAs”) have on-chip global pixel operation capability for extracting a single transient-feature (i.e., single-frequency discrimination) in a snapshot that depends on the number of counters implemented per pixel. However, these DFPA systems are not capable of multi-target and multi-frequency discrimination. Imagers described herein achieve multi-target transient signature discrimination orders of magnitude faster than the readout frame rate using in-pixel electronic shuttering with a known time-encoded modulation. Three-dimensional (x,y,t) data cube reconstruction is performed using compressive sensing algorithms.