Single-Lens 3D Imaging with Central Aperture
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Solution Overview
Problem
Existing three-dimensional (3-D) imaging techniques face challenges in achieving precise quantitative measurements due to issues with dynamic range, diffraction effects, and the complexity of processing blurred images, which are exacerbated by the need for multiple sensors and complex algorithms in single-lens, single-sensor systems.
Innovation Solution
A single-lens, single-sensor 3-D imaging device with a central aperture and off-axis defocusing apertures that use optical filters and a processor to distinguish between background and defocused images, allowing for the reconstruction of 3-D images by measuring the lateral offset and size of image triangles formed by the apertures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a large aperture is used to capture more light, then the imaging system can capture sufficient light energy, but the defocused points appear blurred occupying large sensor space requiring sophisticated algorithms
Solution Approach 1:
The aperture is segmented into multiple sub-apertures arranged in specific patterns. Each sub-aperture captures light from different angular directions, creating spatially separated image samples on the sensor. This segmentation allows the system to maintain a large effective aperture for light capture while avoiding the formation of large blurred discs, as each sub-aperture produces a smaller, distinct image region.
Solution Approach 2:
The patent transitions from measuring depth through blur size (2D intensity distribution) to measuring depth through lateral displacement of image samples (spatial position in 2D). By arranging sub-apertures to create laterally shifted image samples, the system encodes depth information in the spatial domain rather than the intensity domain, simplifying the measurement process and reducing algorithmic complexity.
2Measurement precision
If blur-based depth measurement is used, then depth information can be obtained from a single image, but the intensity measurement is sensitive to brightness differences requiring extremely high dynamic range sensors
Solution Approach 1:
The patent changes the measurement dimension from intensity (brightness) to position (spatial location). Instead of measuring how bright a blurred region is to infer depth, the system measures the lateral position of image samples formed by different sub-apertures. This positional measurement is inherently more robust to intensity variations and does not require extreme dynamic range capabilities.
Solution Approach 2:
The patent replaces photometric measurement (intensity-based) with geometric measurement (position-based). By using the spatial arrangement of image samples rather than their intensity values, the system substitutes a measurement approach that is less sensitive to lighting conditions and object brightness, thereby reducing sensor dynamic range requirements.
3Measurement precision
If multiple defocusing apertures are used to improve 3-D imaging accuracy, then measurement precision improves, but sensor overcrowding increases making image processing more complex
Solution Approach 1:
The aperture is divided into multiple sub-apertures that are spatially distributed. Each sub-aperture creates a distinct, localized image sample on the sensor. This segmentation allows multiple depth-sampling channels to coexist on the same sensor without excessive overlap, as each sub-aperture's image contribution is spatially separated according to its position in the aperture plane.
Solution Approach 2:
The patent uses the spatial arrangement of sub-apertures in the aperture plane to create corresponding spatial patterns on the sensor. By mapping aperture geometry to sensor pattern geometry, the system efficiently packs multiple measurement channels into the available sensor area without requiring excessive sensor real estate, as the pattern is determined by the aperture configuration rather than requiring separate sensor regions.
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 simplifies 3-D imaging by reducing the dynamic range issues and sensor overcrowding, enabling precise and cost-effective 3-D mapping and surface inspection with improved robustness and accuracy.
Implementation Method 1
a lens, a central aperture located along an optical axis for projecting an entire image of a target object
Implementation Method 2
A single-lens, single-sensor 3-D imaging device with a central aperture and off-axis defocusing apertures that use optical filters
Data Source
AI summary
A device and method for three-dimensional (3-D) imaging using a defocusing technique is disclosed. The device comprises a lens, a central aperture located along an optical axis for projecting an entire image of a target object, at least one defocusing aperture located off of the optical axis, a sensor operable for capturing electromagnetic radiation transmitted from an object through the lens and the central aperture and the at least one defocusing aperture, and a processor communicatively connected with the sensor for processing the sensor information and producing a 3-D image of the object. Different optical filters can be used for the central aperture and the defocusing apertures respectively, whereby a background image produced by the central aperture can be easily distinguished from defocused images produced by the defocusing apertures.