Digital Micromirror Device Varies Integration Times for High Dynamic Range Imaging
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Solution Overview
Problem
Conventional imaging systems face challenges in capturing high dynamic range images effectively, particularly in environments with varying light conditions, leading to issues with noise and image quality due to limitations in dynamic range and exposure control.
Innovation Solution
The implementation of a digital micromirror device (DMD) that varies effective integration times and employs interpolation, spectral density estimation, and noise reduction techniques to reconstruct high dynamic range video, using pseudorandom exposure patterns and efficient algorithms to improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional image detectors are used to capture images in varying light conditions, then the device structure remains simple, but the dynamic range and image quality deteriorate due to noise and saturation
Solution Approach 1:
The detector array is divided into multiple independently controllable detector elements, each capable of individual exposure control. This segmentation allows different regions to capture images at different exposure times, enabling high dynamic range imaging without requiring complex additional hardware
Solution Approach 2:
The patent implements dynamic exposure control where the integration time of each detector element is dynamically adjusted based on local scene brightness. Bright regions use short integration times to avoid saturation while dark regions use long integration times to capture sufficient signal, achieving HDR capability through temporal dynamics rather than structural complexity
2Adaptability or versatility
If a single integration time is used for all detectors, then the device operation is simple, but the dynamic range capability is limited and cannot capture both bright and dark regions effectively
Solution Approach 1:
Each detector element is assigned a specific integration time based on its local scene requirements. Bright regions are assigned short integration times while dark regions are assigned long integration times, creating spatially varying exposure characteristics that match the local luminance distribution, thereby achieving high dynamic range capture
Solution Approach 2:
The integration time parameter is varied across different detector elements and across time to capture a wide dynamic range. By changing the integration time parameter dynamically rather than using a fixed value, the system adapts to varying scene conditions and captures both bright and dark regions effectively
3Reliability
If multiple images with different exposure times are captured and combined, then the dynamic range is improved, but the processing time and computational complexity increase
Solution Approach 1:
The patent performs preliminary organization of image data during the capture phase, where detector elements are pre-assigned to different integration time groups. This preliminary structuring of data enables more efficient processing during combination, reducing the computational burden compared to processing completely independent images
Solution Approach 2:
Multiple images captured with different integration times are merged into a single high dynamic range image. By combining the information from short-exposure images (capturing bright regions) and long-exposure images (capturing dark regions), the system achieves extended dynamic range while processing the data in an optimized manner
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 the capture of noise-free high dynamic range video with improved image quality, effectively addressing the limitations of conventional systems by varying integration times and using advanced algorithms for exposure control and noise reduction.
Implementation Method 1
a digital micromirror device (DMD) that varies effective integration times
Implementation Method 2
As an example, a plurality of sensors may be provided in an image detector array to detect electromagnetic radiation at desired wavelengths
Data Source
AI summary
A system comprises a digital micromirror device (DMD), an image sensor comprising an array of sensors operable to capture an image of a scene, a readout integrated circuit (ROIC) operable to generate signals from the sensors corresponding to the captured image of the scene, and an image reconstruction module. The image sensor is operable to capture an image of a scene and comprises an array of photodetector sensors operable to capture an image of a scene at a first frame rate, and a read a readout integrated circuit (ROIC) operable to generate signals from the photodetector sensors corresponding to the captured image of the scene at a second frame rate. A digital micromirror device (DMD) comprising a plurality of micromirrors, each micromirror having at least two physical states, and control circuitry operable to separately control the state of each micromirror, the digital micromirror device operable to receive the image of a scene and reflect the image to the image sensor, whereby the image sensor captures the reflected image of the scene. A processing component is operable to control the operation of the DMD and reconstruct the image from the ROIC.