Smart Photonic Imaging Using DMD Segmentation
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Solution Overview
Problem
Conventional optical imaging systems, particularly those using CCD/CMOS sensors, struggle with capturing high dynamic range images under bright light conditions due to saturation and inter-pixel crosstalk, which distorts the scene and renders it unobservable.
Innovation Solution
The method involves using a Digital Micromirror Device (DMD) to physically separate brighter and less bright pixels, capturing them in separate images, and then combining these images to accurately measure the scene, while also employing time modulation and CDMA signal processing to enhance image detection and reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a CCD/CMOS sensor is used to capture images under bright light conditions, then the sensor can detect the scene, but pixel saturation and inter-pixel crosstalk occur causing image distortion and loss of observability
Solution Approach 1:
The patent segments the image capture process into multiple exposure frames, where each frame captures a specific brightness range. The DMD device divides the scene into different brightness zones and directs them to appropriate detectors or adjusts exposure times differently for different regions, preventing saturation while maintaining detection capability across the full dynamic range.
Solution Approach 2:
The system dynamically adjusts the exposure time and DMD mirror states for different pixels based on their brightness levels. By making the exposure parameters variable rather than fixed, the system can adapt to local brightness conditions, capturing both bright and dark regions without saturation or excessive noise.
2Use of energy by moving object
If the exposure time is increased to capture brighter pixels, then more light is detected, but saturation occurs and distorts the image
Solution Approach 1:
Different regions of the image receive different exposure treatments based on their local brightness characteristics. Bright regions use shorter exposure times or attenuation, while dark regions use longer exposure times, with each region optimized independently for its specific lighting conditions.
3Measurement precision
If the exposure time is decreased to avoid saturation of bright pixels, then saturation is reduced, but darker pixels are underexposed and lose detail
Solution Approach 1:
The image is segmented into multiple brightness zones that are captured in separate exposures. Each zone is captured with exposure parameters optimized for its brightness level, ensuring that both bright and dark regions are captured with adequate detail without cross-contamination from saturation or underexposure.
4Measurement precision
If a DMD is used to scan pixels serially to eliminate crosstalk, then inter-pixel crosstalk is eliminated, but image capture speed decreases
Solution Approach 1:
Instead of scanning every pixel serially, the system applies serial scanning only to specific regions or pixels that require high precision irradiance measurement. Other regions can be captured using faster parallel methods, achieving a balance between measurement precision and capture speed by applying the precise but slow method only where necessary.
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 dynamic range optical image detection, minimizing distortion and saturation, and achieving spatial resolution beyond the Abbe diffraction limit, thereby producing a true and undistorted image even in extreme lighting conditions.
Implementation Method 1
a Digital Micromirror Device (DMD) can be used an agile pixel optical irradiance sampler. The DMD can direct sampled light in the optical irradiance 2-D map to a single point detector (PD)
Implementation Method 2
The DMD can direct sampled light in the optical irradiance 2-D map to a single point detector (PD)
Data Source
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AI summary
The present invention provides a method for performing high dynamic range optical image detection of a scene comprising: imaging incident light from a scene onto an object plane; determining the locations of those pixels in the object plane of higher brightness; detecting the optical irradiance values of those pixels of higher brightness to produce a first detected image; detecting the optical irradiance values of those pixels of lower brightness to produce a second detected image; and generating a high dynamic range optical irradiance map of the scene by combining the first detected image and the second detected image into a single image.