Hadamard Enhanced Sensor Using Walsh-Hadamard Mask
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Solution Overview
Problem
Conventional electronic imaging techniques face limitations in increasing pixel density due to manufacturing constraints and the need for smaller detector arrays with higher resolution, as existing methods do not effectively enhance pixel count without compromising detector resolution or increasing physical footprint.
Innovation Solution
The use of Walsh-Hadamard masks, specifically two-dimensional Walsh-Hadamard filter patterns, positioned in front of light detectors to control light passage and project images onto a detector array, combined with a lens assembly and an actuator to move the mask, detectors, or image, allowing for sequential data measurement and inverse Walsh-Hadamard transform processing to increase pixel count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing techniques are used to assemble detector arrays, then detector resolution and pixel density are limited, but increasing pixel density requires smaller physical footprints which compromises manufacturing capability
Solution Approach 1:
The invention divides the detection task into multiple segments by using a mask with multiple subarrays that sequentially mask different portions of the scene. Each subarray captures a portion of the image, and through computational processing, these segments are combined to reconstruct a high-resolution image from the limited physical detectors, effectively segmenting both the optical path and data processing
Solution Approach 2:
The invention transitions from a two-dimensional detector array to a three-dimensional solution by adding the temporal dimension through sequential masking and the computational dimension through algorithms. This allows the system to achieve higher effective pixel density by utilizing time-multiplexed measurements and computational reconstruction rather than relying solely on physical detector density
2Measurement precision
If the number of detectors is increased to improve pixel density, then image resolution improves, but the physical footprint and device complexity increase
Solution Approach 1:
The mask structure serves multiple functions: it acts as an optical element to control light passage, a spatial encoder to impose pattern information on the scene, and a data multiplexer to sequentially present different subarrays to the detector. This multi-functionality allows a single physical component to replace what would otherwise require multiple separate systems
Solution Approach 2:
The mask with Walsh-Hadamard patterns acts as an intermediary between the scene and the detector array. It transforms the optical information into a coded format that can be captured by fewer detectors, then computational algorithms act as a second intermediary to decode and reconstruct the high-resolution image, effectively mediating the information transfer without requiring proportional increases in detector count
3Quantity of substance
If sequential masking is used to increase pixel count, then pixel density increases by the mask subarray factor, but measurement time and data processing complexity increase
Solution Approach 1:
The mask sequentially presents different subarrays to the detector in a periodic manner, with each subarray being displayed for a fixed integration time. This periodic action allows the system to accumulate measurements over time efficiently, with the total measurement time being the product of the number of subarrays and the integration time per subarray, achieving high pixel counts through time-multiplexed measurements
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 significantly increases pixel density by a factor corresponding to the pattern mask subarray size, enhancing image resolution without increasing the physical footprint of the detector array, as demonstrated by the 4x4 Walsh-Hadamard array increasing pixel density by a factor of 16.
Implementation Method 1
positioning a lens assembly in front of the mask to project an image through the mask filter patterns on to the plurality of light detectors
Implementation Method 2
measuring the filtered image projected through the mask with the plurality of light detectors
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A method for increasing the pixel count delivered from a plurality of light detectors when scanning an object that includes positioning a mask, having a plurality of two dimensional Walsh-Hadamard filter patterns, in front of a plurality of light detectors to control the passage of light through the mask filter patterns to the light detectors. The method also includes positioning a lens assembly in front of the mask to project an image through the mask filter patterns on to the plurality of light detectors. The method also includes moving the mask, plurality of light detectors, or the image in a plane defined by a planar surface of the plurality of light detectors. The method also includes measuring the filtered image projected through the mask with the plurality of light detectors.