Continuous Diamond Color Grading With Rotating-Plate Calibration
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Solution Overview
Problem
Existing automated diamond color grading systems suffer from inaccuracies and inefficiencies, particularly in distinguishing between closely graded diamonds, requiring manual intervention and precise calibration, and are often expensive or slow.
Innovation Solution
A continuous diamond color grading machine with a rotating plate system that compares sample diamonds to a set of master stones under uniform lighting, using a camera to capture images at multiple angles, and a computer to analyze and sort diamonds based on their color grades, correcting for operational offsets through internal referencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual color grading by trained observers is used, then accurate color evaluation can be achieved, but the process is time-consuming and requires specialized training
Solution Approach 1:
The patent replaces the manual mechanical inspection process with an automated optical-mechanical system. A camera captures images of diamonds under controlled lighting, and a computer automatically analyzes color values, substituting the trained observer's visual assessment with machine-based measurement and computation.
Solution Approach 2:
The system performs self-calibration by automatically establishing color standards using reference diamonds captured in the same session. The computer identifies master stones and creates a calibration curve without requiring manual intervention, allowing the system to grade diamonds independently and continuously.
2Productivity
If automated color grading machines are used, then grading speed increases, but measurement precision deteriorates due to inability to distinguish closely graded diamonds
Solution Approach 1:
The system uses feedback from captured images to continuously refine color measurements. The computer analyzes the captured images, compares them against calibration standards, and adjusts grading decisions based on the measured color values, enabling precise differentiation of closely graded diamonds through iterative measurement and comparison.
Solution Approach 2:
The patent transforms the visual assessment task into quantitative parameter measurement by capturing digital images and extracting color values (such as CIE L*a*b* coordinates). This parameter-based approach allows the system to measure and compare color differences objectively, achieving precision in distinguishing closely graded diamonds through numerical analysis rather than visual judgment.
3Measurement precision
If precise calibration is implemented, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The system performs self-calibration by automatically identifying master stones from the captured images and establishing color standards without requiring manual calibration procedures. The computer algorithm automatically determines which diamonds serve as references and creates the calibration curve, eliminating the need for complex external calibration equipment and procedures.
Solution Approach 2:
The calibration process is performed preliminarily and automatically at the beginning of each grading session. The system captures images of reference diamonds, establishes the calibration curve, and stores the color standards before proceeding to grade sample diamonds, ensuring precision is built into the system beforehand rather than requiring complex real-time adjustments.
4Measurement precision
If multiple trials are conducted to improve accuracy, then measurement precision improves, but loss of time increases due to repeated measurements
Solution Approach 1:
The system performs continuous grading without interruption between samples. Once calibrated, the automated system can grade diamonds continuously by capturing images and automatically analyzing color values, eliminating the time losses associated with resetting or re-calibrating between individual diamond assessments that would occur in manual processes.
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
Achieves accurate diamond color grading within +/- 0.5 grades without manual calibration, enabling efficient, automated, and cost-effective sorting of diamonds by color.
Implementation Method 1
a camera to capture images at multiple angles, and a computer to analyze and sort diamonds based on their color grades
Data Source
AI summary
An automated diamond color-grading machine color grades a continuous line of diamonds without human color evaluation. A sample diamond is carried by an input conveyor and placed on a mount on a rotating plate by a robotic arm. The rotating plate has Nm mounts with Nr master stones of known color grades and Ns sample diamonds. A camera takes a photo of the rotating plate with all diamonds and then a step motor rotates the plate by 360/Nm degrees and another photo captured. This is repeated Nm times so that the sample diamond and all master stones are each imaged in all Nm possible rotational positions. Pixels are averaged over all positions for each diamond to get an average x,y value for each diamond. The color grade of the sample diamond is the master stone with the closest less-color x,y average.