Optical Sorter Light Timing for Grain Defect Detection
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Solution Overview
Problem
Existing optical sorting apparatuses struggle to accurately distinguish defective grains such as milky, green immature, and colored grains in brown rice or milled rice, as well as other granular objects, due to limitations in distinguishing based on optical information.
Innovation Solution
An optical sorter with intermittent light sources and sensors that control lighting periods to prevent light mixing between scan periods, using multiple light sources and sensors on opposite sides to detect reflected and transmitted light, and incorporating near-infrared and visible light for enhanced detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light source is turned on continuously during all scan periods, then the detection coverage is maximized, but light from adjacent scan periods mixes into current scan period detection results causing noise
Solution Approach 1:
The light source is controlled to operate periodically with distinct lighting periods and non-lighting periods that correspond to the scan period timing. The light source is turned on only during the lighting period of each scan period and turned off during non-lighting periods, ensuring that light is emitted only when needed for current scan detection and not during adjacent scan periods, thereby preventing light mixing and noise contamination.
2Speed
If the lighting period starts at the same time as the scan period, then detection begins immediately, but light from the current scan period mixes into the previous scan period detection results
Solution Approach 1:
The light source control is configured so that the lighting period starts at a timing delayed behind the start of the scan period. This preliminary timing adjustment ensures that when the scan period begins, the light source has already been turned off from the previous cycle, preventing light from the current scan period from mixing into the previous scan period detection results while still maintaining adequate detection response time.
3Duration of action of moving object
If the lighting period ends at the same time as the scan period, then the full scan duration is utilized, but light from the previous scan period mixes into the current scan period detection
Solution Approach 1:
The light source control is configured so that the lighting period ends at a timing earlier than the end of the scan period. This preliminary termination of light emission prevents light from the previous scan period from mixing into the current scan period detection results. By turning off the light source before the scan period ends, the system eliminates the harmful effect of light contamination while maintaining sufficient light emission duration for accurate detection.
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
The system increases the accuracy of distinguishing defective products by reducing noise interference and allowing simultaneous detection of multiple light wavelengths, enabling precise identification of various types of defects.
Implementation Method 1
an intermittent light source configured to intermittently emit light toward a plurality of sorting targets in transit, an optical sensor configured to detect the light associated with one sorting target among the plurality of sorting targets in transit
Implementation Method 2
using multiple light sources and sensors on opposite sides to detect reflected and transmitted light
Implementation Method 3
using multiple light sources and sensors on opposite sides to detect reflected and transmitted light
Data Source
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AI summary
An optical sorter includes an intermittent light source configured to intermittently emit light toward a plurality of sorting targets in transit, an optical sensor configured to detect the light associated with one sorting target among the plurality of sorting targets in transit during a plurality of intermittent light scan periods, a determination part configured to determine a foreign object and/or a defective product with respect to the one sorting target based on a signal acquired by the optical sensor, and a light source control part configured to control the intermittent light source. The light source control part is configured to control the intermittent light source in such a manner that, in a case where the intermittent light source is turned on during at least one intermittent light scan period among the plurality of intermittent light scan periods, a lighting period during which the intermittent light source is on and a non-lighting period during which the intermittent light source is off are provided and the lighting period is started at a timing delayed behind a start of the at least one intermittent light scan period in each of the at least one intermittent light scan period.