Optical Sorter Transit Speed Calculation via Color Shift

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Solution Overview

Problem

Existing optical sorters face challenges in accurately calculating the transit speed of sorting targets when multiple targets with similar shapes are conveyed simultaneously, leading to reduced sorting accuracy due to difficulties in determining whether the targets detected by different sensors are the same.

Innovation Solution

An optical sorter equipped with a color sensor featuring R, G, and B element groups spaced apart in the transit direction, which calculates transit speed based on color shift amounts between images from these elements, eliminating the need to determine if targets at different points are the same and allowing for more accurate speed calculation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If two optical sensors are used to calculate transit speed, then the transit speed can be calculated automatically, but it becomes difficult to determine whether the detected targets are the same when multiple similar targets are conveyed simultaneously

Engineering Contradiction:
Improveautomatic determination of delayed timeVSAvoidtransit speed calculation accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent divides a single color sensor into multiple element groups (R, G, B) spaced at different positions in the transit direction. Each element group acts as an independent detection point, allowing the system to calculate transit speed by measuring color shifts between these segmented elements rather than requiring separate sensors to track the same target.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes color shift information detected by the color sensor to calculate transit speed. By measuring the color shift that occurs as light passes through different element groups spaced in the transit direction, the system can determine speed without needing to identify and track the same target across multiple sensors, thus avoiding the ambiguity problem.

Inventive Principle:
Principle #32Color changes

2Productivity

If multiple sorting targets are conveyed simultaneously to secure processing capacity, then productivity increases, but the ability to determine whether targets at different points are the same decreases

Engineering Contradiction:
Improveprocessing capacityVSAvoidsorting accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces the mechanical approach of using multiple sensors to track the same target with an optical field-based approach. By utilizing color shift measurements across spatially separated element groups within a single sensor, the system calculates transit speed based on optical field distribution rather than mechanical target identification and tracking.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables more precise calculation of transit speed, reducing errors and improving sorting accuracy by using a single color sensor to determine the speed of sorting targets, even when multiple targets are conveyed simultaneously.

Implementation Method 1

a color sensor which includes an R element group, which is a plurality of optical elements for detecting light having a wavelength corresponding to red, a G element group, which is a plurality of optical elements for detecting light having a wavelength corresponding to green, and a B element group, which is a plurality of optical elements for detecting light having a wavelength corresponding to blue

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a color sensor which includes an R element group, which is a plurality of optical elements for detecting light having a wavelength corresponding to red

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP4115996B1Optical sorting machine
Publication Date: 2025.01.08 SATAKE CORP
  • EP4115996B1 patent drawingFigure 1
  • EP4115996B1 patent drawingFigure 2
  • EP4115996B1 patent drawingFigure 3

AI summary

An optical sorter includes a light source, a color sensor, a determination part configured to determine a foreign object and/or a defective product, a color shift amount calculation part configured to calculate, based on a color image acquired by the color sensor, an amount of a color shift that occurs due to the fact that at least two element groups out of an R element group, a G element group, and a B element group are spaced apart from each other in a transit direction of a sorting target, a speed calculation part configured to calculate a transit speed of the sorting target based on a separation distance between the at least two element groups in the transit direction, the color shift amount, and a scan time, which is a time required for the color sensor to scan the sorting target once, and a sorting device configured to perform a trajectory change operation for changing a trajectory of a specific sorting target determined based on a result of the determination by the determination part at a timing determined based on the transit speed calculated by the speed calculation part.