Bulk Object Detection Using Focused Light and Asymmetric Geometry
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Solution Overview
Problem
Current systems for non-destructive evaluation of fruit and vegetables, such as those using NIR and VIS spectroscopy, require objects to be analyzed individually, leading to low throughput and inefficiency in grading and sorting processes.
Innovation Solution
An apparatus with bulk feeding means and a light source with a focusing element that illuminates objects moving in a detecting region, combined with a light-analyzing apparatus capable of sensing transmitted light, which discriminates between light from the source and ambient light, allowing for efficient detection and sorting of multiple objects simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If objects are analyzed one by one using traditional NIR/VIS spectroscopy systems, then measurement precision is maintained, but productivity is significantly reduced
Solution Approach 1:
The system divides the detection process into multiple independent detection zones along the conveyor belt path, with multiple light sources and detectors operating simultaneously at different positions. This allows multiple objects to be analyzed in parallel while maintaining individual measurement accuracy for each object.
Solution Approach 2:
The system transitions from single-point sequential measurement to multi-point spatial measurement by arranging light sources and detectors at different positions in three-dimensional space. Objects are illuminated from multiple angles and detected at multiple locations simultaneously, enabling parallel processing while maintaining measurement precision through geometric separation.
2Productivity
If multiple objects are fed simultaneously into the detection region, then productivity increases, but measurement precision deteriorates due to light interference and ambient noise
Solution Approach 1:
The system employs multiple independent light source-detector pairs positioned at different locations, each creating a localized measurement zone. Each detector primarily receives light from its corresponding light source through the object at its specific position, reducing cross-interference. The geometric arrangement ensures that each measurement point has high local signal-to-noise ratio even when multiple objects are processed simultaneously.
Solution Approach 2:
The system extracts and separates the useful transmitted light signal from ambient light interference by using focused light sources and corresponding detectors positioned to receive only the transmitted light path. The geometric configuration allows the system to isolate the measurement signal from background ambient light, maintaining precision in bulk processing mode.
3Measurement precision
If the light source illuminates objects in a direction within the detector's field-of-view, then detection sensitivity increases, but ambient light interference increases
Solution Approach 1:
The system uses asymmetric geometric arrangement where light sources and detectors are positioned at specific non-symmetric angles relative to the object path. The light source illuminates objects from one direction while the detector is positioned to receive transmitted light at a different angle, creating an asymmetric optical path that favors the transmitted signal while rejecting ambient light from other directions.
Solution Approach 2:
Instead of positioning the detector to face the light source directly (which would increase ambient light sensitivity), the system inverts the arrangement by positioning the detector to receive light transmitted through the object from the light source. The detector looks away from the light source direction, using the object itself as the optical element to redirect the light into the detector, thereby rejecting ambient light while maintaining detection sensitivity.
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 solution significantly increases the throughput of objects being evaluated by ensuring that only light transmitted through objects is detected, reducing noise from ambient light and enabling the determination of internal parameters like sugar content, acidity, and rot, while allowing for the sorting of objects based on these parameters.
Implementation Method 1
Transmitted light, i.e. radiation that penetrates the object, is subjected to scattering and/or absorption which affect its wavelength. These changes depend on the light-scattering properties of the object, as well as its chemical composition.
Implementation Method 2
In NIR or VIS spectroscopy, the object subjected to analysis is irradiated, and the reflected or transmitted radiation is measured. Changes in the reflected light are analysed to determine various characteristics of the surface of the object.
Data Source
AI summary
An apparatus for detecting matter comprises bulk feeding means configured for feeding a plurality of objects into a detecting region; at least one light source having a focusing element and being configured for illuminating at least one object moving in an object plane in the detecting region; and a first light-analyzing apparatus arranged to sense light that has been transmitted through the object. In the associated method, the object is caused to move in the plane and the object is illuminated with incident light. Light that has been transmitted through the object and is falling in a measuring plane is detected, and an object-specific parameter based on the detected transmitted light is determined.