Ptychographic Imaging System LED Weighting
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Solution Overview
Problem
Conventional Fourier ptychographic imaging systems face challenges in generating high-quality images in a short time due to geometric effects and redundant information from light sources, leading to reduced power density and increased reconstruction time.
Innovation Solution
A ptychographic imaging system with a plurality of light sources arranged in a predefined pattern, where the pattern compensates for geometric effects, and a controller that adapts the operation of the light sources to optimize signal-to-noise ratio and reduce the number of required images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional uniform LED arrays are used with high angle of incidence, then large field of view and high resolution are achieved, but power density at the sample plane is reduced due to cosine effect
Solution Approach 1:
The patent applies local quality by varying the spatial distribution of LED intensities according to their positions in the array. LEDs at different locations have different emission weights assigned to them, with LEDs at higher angles having reduced intensity to compensate for the cosine effect. This local adjustment of illumination quality maintains uniform power density across the sample plane while preserving the large field of view and high resolution benefits.
2Measurement precision
If light sources further from central optical axis are used, then larger numerical aperture is achieved, but redundant information is collected
Solution Approach 1:
The patent changes the parameter of LED emission weights based on their angular positions. By assigning different weights to LEDs at different distances from the central optical axis, the system optimizes the information content collected. This parameter adjustment ensures that LEDs contributing redundant information have their weights reduced, while maintaining the high numerical aperture capability for improved measurement precision.
3Measurement precision
If multiple images are captured sequentially for Fourier ptychography reconstruction, then high resolution image is generated, but reconstruction time is increased
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal emission weights for each LED based on their positions and the desired field of view. This preliminary setup creates a weighting map that guides the illumination process, allowing the system to capture necessary images more efficiently. The pre-planned illumination strategy reduces the number of sequential images needed and optimizes the capture process, thereby reducing reconstruction time while maintaining high resolution.
4Device complexity
If conventional planar uniform light source arrangement is used, then simple device structure is maintained, but geometric effects reduce image quality
Solution Approach 1:
The patent transforms the uniform light source arrangement into a non-uniform one by assigning position-dependent emission weights to each LED. This local quality adjustment compensates for geometric effects such as the cosine effect and varying path lengths. The weighted illumination approach maintains the simple planar structure while significantly improving image quality by accounting for the different geometric conditions of each light source position.
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
The system achieves high-quality images with improved signal-to-noise performance and reduced reconstruction time, allowing for higher throughput and enhanced contrast, particularly beneficial for applications like lab diagnostics.
Implementation Method 1
Conventional uniform LED arrays have the effect that due to the high angle of incidence, geometrical reduction of available power density at the sample plane becomes relevant. The reduction scales with the cosine of the angle of incidence
Implementation Method 2
Digital imaging and fast computer systems offer the opportunity to generate high-resolution images by analytically merging low-resolution sub-images. These computational methods of microscopic imaging comprise ptychography which generates images by processing coherent interference patterns that have been scattered from a sample.
Implementation Method 3
Fourier ptychography imaging systems are advantageous for having a large field of view and a high resolution. A large number of individual images are illuminated by different numerical aperture settings. Quasi collimated and thus (spatially) coherent illumination is used with large angles of incidence. For Fourier ptychography reconstruction, a requirement is to collect Fourier spectra with at least 50 percent overlap.
Data Source
AI summary
The invention relates to a ptychographic imaging system that includes a plurality of light sources adapted to emit light onto a sample location, wherein the light sources are arranged in a predefined pattern; the system also includes a controller adapted to control operation of the plurality of light sources; wherein at least one of a) the predefined pattern of the light sources and b) the operation of the plurality of light sources is adapted to compensate for geometric effects due to an arrangement of the light sources relative to the sample location.