Optical Object Detection Using Multi-Wavelength Spectral Filtering
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Solution Overview
Problem
Current methods for detecting animals in agricultural areas, such as those used in harvesting and mowing, often fail to differentiate between animals and their surroundings effectively, leading to accidents and injuries, particularly due to the disruptive influence of ambient light and the behavior of young animals staying hidden.
Innovation Solution
A device with a sensor unit that uses a combination of radiation sources emitting at specific wavelengths (around 940 nm and 1350-1500 nm) to illuminate a measurement spot, a detector to measure reflected radiation intensities, and a filter to minimize ambient light interference, allowing for the differentiation of animals from grass, earth, or stones based on spectral reflectance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ambient light is used for illumination, then the device complexity is reduced, but the measurement precision deteriorates due to interference from ambient light
Solution Approach 1:
The patent uses specific wavelength parameters (940 nm and 1350-1500 nm) for the radiation sources to illuminate the measurement spot. These wavelengths are chosen because they are not present in ambient sunlight, allowing the detector to distinguish reflected radiation from the radiation source against the background of ambient light, thereby maintaining measurement precision without requiring complex ambient light blocking mechanisms
Solution Approach 2:
The patent introduces a filter device as an intermediary component between the detector and the measurement spot. This filter selectively transmits only the specific wavelengths (940 nm and 1350-1500 nm) while blocking other wavelengths, including ambient light interference, thereby enabling precise measurements without requiring complex ambient light exclusion systems
2Measurement precision
If multiple wavelengths are used to improve detection accuracy, then the measurement precision is improved, but the device complexity increases due to multiple radiation sources and filters
Solution Approach 1:
The patent combines multiple radiation sources (940 nm and 1350-1500 nm wavelengths) into a single integrated illumination system, and merges the filtering function into a unified filter device that handles both wavelengths simultaneously. This merging approach enables multi-wavelength detection with improved accuracy while keeping the overall device structure relatively simple and compact
3Productivity
If continuous illumination is used, then the productivity is improved through continuous measurement, but the use of energy increases
Solution Approach 1:
The patent employs periodic pulsed illumination instead of continuous illumination. The radiation sources emit light in periodic pulses synchronized with the measurement cycle, allowing continuous productivity through rapid repeated measurements while significantly reducing overall energy consumption compared to continuous operation. The pulsed mode also helps distinguish reflected radiation from ambient light through temporal gating
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 enhances detection security and reliability by clearly distinguishing animals from their environment, reducing false alarms and enabling timely avoidance of collisions, with the system capable of continuous and rapid measurements to compensate for fluctuating light conditions.
Implementation Method 1
the radiation source comprises at least a first transmitter with a first wavelength A1 with a value of about 940 nm or around 1130 nm and a second transmitter with a second wavelength λ2 with a value of 1350-1500 nm
Implementation Method 2
a detector for measuring the intensity of radiation from the measurement spot
Implementation Method 3
a filter device is arranged in front of the detector, wherein radiation with at least two different spectral ranges can be selected by the filter device
Implementation Method 4
the behavior of the reflectance of the object in the measurement spot can be determined by the evaluation unit from the intensity values measured by the detector
Data Source
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AI summary
The invention relates to a device and a method for the optical detection of different objects, comprising a sensor unit for the electromagnetic detection of the objects on an agricultural area. The sensor unit includes at least one radiation source for illuminating a measurement spot and at least one detector for measuring the intensity of radiation from the measurement spot. A control device is provided by which the radiation source and the detector can be operated in an electrically clocked manner. A filter device is arranged upstream of the detector, by which radiation with at least two different spectral ranges can be selected. The radiation source comprises at least a first transmitter with a first wavelength λ1 and a second transmitter with a second wavelength λ2.An evaluation unit is designed to determine the reflectance behavior of the object in the measurement spot from the intensity values measured by the detector, which occur when irradiated with the different wavelengths.