System and method for selecting a quality grade metric profile for assuring optimal control of symbol quality in a DPM process

Patent metadata

Field	Value
Publication number	US-11907793-B2
Application number	US-201816958547-A
Country	US
Kind code	B2
Filing date	Dec 20, 2018
Priority date	Dec 28, 2017
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A computer-implemented system and process of producing a metric quality grade profile for use during inspection of DPM symbol marked on parts may include storing average metrics measured in a controlled environment for a “golden” sample. Measurements of the DPM symbol of the “golden” sample may be performed. Measurements of the metrics of the “golden” sample in an uncontrolled environment may be performed. Average metrics from the uncontrolled environment may be calculated. The averaged metrics from the controlled and uncontrolled environment may be compared. The user may be enabled to set an acceptable grade for the individual metrics. The acceptable grades for the individual metrics as a profile of the DPM symbol in memory.

First claim

The invention claimed is:

1. A system for inspecting direct part marking (DPM) symbols, comprising:
an imaging device configured to capture images of DPM symbols on parts being processed by equipment;
a non-transitory memory configured to store a profile inclusive of acceptable grades for each of a plurality of individual metrics of the DPM symbols; and
a processing unit in communication with said imaging device and said non-transitory memory, and configured to:
store, in the non-transitory memory, official metrics measured in a controlled environment for a “golden” sample;
receive, from the imaging device, a captured image of a DPM symbol on a part;
image process the captured image to perform measurements of the DPM symbol of the “golden” sample and determine a grade of each of the individual metrics of the imaged DPM symbol based on calculate statistical distributions of the individual metrics from an uncontrolled environment;
for each of the metrics, compare the official individual metrics from the controlled environment and the statistical distributions of the individual metrics from the uncontrolled environment to determine whether a determined grade of the corresponding metric of the imaged DPM symbol is below the acceptable grade of the corresponding metric; and
identify the individual metrics that are lower in the uncontrolled environment, and in response to determining that a grade of a corresponding metric the imaged DPM symbol is below an acceptable grade for the corresponding metric, communicate a first signal to the equipment for the equipment to perform a first physical action in processing the part, otherwise, communicate a second signal to the equipment for the equipment to perform a second physical action in processing the part.

2. The system according to claim 1 , wherein said processing unit is further configured to:
enable a user to establish an acceptable grade for each of the metrics, at least one of the acceptable grades being different from at least one of the other acceptable grades; and
store the user-established acceptable grades in the non-transitory memory.

3. The system according to claim 2 , wherein said processing unit is further configured to enable a user to set a value for a specific metric to be ignored to avoid determining that the specific metric failed during inspection.

4. The system according to claim 3 , wherein said processing unit is further configured to calculate an overall metric based on the individual metrics that are not set to be ignored.

5. The system according to claim 1 , wherein said processing unit is further configured to automatically generate the profile of acceptable grades by selecting a lowest grade measured on a set of a plurality of measurements on the “golden” sample for each metric.

6. The system according to claim 1 , wherein said processing unit is further configured to generate a list of part identifiers and measured individual metrics associated with the part identifiers.

7. The system according to claim 1 , wherein said processing unit is further configured to:
determine whether any of the individual metrics are degrading over multiple parts being inspected; and
generate a report that indicates that an individual metric is trending downward over time.

8. The system according to claim 1 , wherein the individual metrics include one or more of a decode metric, a cell contrast metric, a cell modulation metric, an unused error correction metric, a print growth metric, an axial non-uniformity metric, a grid uniformity metric, a fixed pattern damage metric, or a minimum reflectance metric.

9. The system according to claim 1 , wherein the grade of each of the individual metrics is one of a letter grade or a numerical grade.

10. A computer-implemented method for inspecting direct part marking (DPM) symbols, comprising:
storing official metrics measured in a controlled environment for a “golden” sample;
performing measurements of the DPM symbol of the “golden” sample;
receiving an image of a DPM symbol on a part;
performing measurements of the metrics of the “golden” sample in an uncontrolled environment;
calculating statistical distributions of metrics from the uncontrolled environment;
comparing the official metrics from the controlled environment and statistical distributions of individual metrics from the uncontrolled environment and determining a grade of each of a plurality of individual metrics of the imaged DPM symbol;
identifying individual metrics that have lower grades in the uncontrolled environment than in the controlled environment;
for each of the metrics, determining whether a determined grade of the corresponding metric of the imaged DPM symbol is below the acceptable grade from a profile of the corresponding metric; and
in response to determining that a determined grade of the corresponding metric is below the acceptable grade of that corresponding metric, communicating a first signal to equipment for the equipment to perform a first physical action in processing the part, otherwise, communicating a second signal to the equipment for the equipment to perform a second physical action in processing the part.

11. The method according to claim 10 , further comprising:
enabling a user to establish an acceptable grade for each of the individual metrics, at least one of the acceptable grades being different from at least one of the other acceptable grades; and
storing the user-established acceptable grades.

12. The method according to claim 11 , further comprising enabling a user to set a value for a specific metric to be ignored to avoid determining that the metric failed during inspection.

13. The method according to claim 12 , further comprising calculating an overall metric based on the individual metrics that are not set to be ignored.

14. The method according to claim 10 , further comprising automatically generating the profile of acceptable grades by selecting a lowest grade for each individual metric measured from a plurality of measurements on the “golden” sample.

15. The method according to claim 10 , further comprising generating a list of part identifiers and measured individual metrics associated with the part identifiers.

16. The method according to claim 10 , further comprising:
determining whether any of the individual metrics are degrading over multiple parts being inspected; and
generating a report that indicates that an individual metric is trending downward over time.

17. A computer-implemented method of producing a metric quality grade profile for use during inspection of a direct part marking (DPM) symbol marked on parts, comprising:
storing official metrics measured in a controlled environment for a “golden” sample;
performing measurements of the DPM symbol of the “golden” sample;
performing measurements of the metrics of the “golden” sample in an uncontrolled environment;
calculating statistical distributions of metrics from the uncontrolled environment;
comparing the official metrics from the controlled environment and statistical distributions of metrics from the uncontrolled environment;
setting an acceptable grade for each of the individual metrics that have lower grades in the uncontrolled environment than in the controlled environment;
configuring an imaging system to perform inspection of direct part marking symbols by storing, in a non-transitory memory on the imaging system, the acceptable grades for the individual metrics as a profile of the DPM symbol;
during inspection of an imaged DPM symbol on a part, accessing the acceptable gr

Assignees

• Datalogic IP Tech Srl

Inventors

• Zocca Rinaldo
• Bassi Lorenzo
• Iannone Clemente

Classifications

• G06K5/04 Primary

  Verifying the alignment of markings · CPC title

• G06F17/18

  for evaluating statistical data {, e.g. average values, frequency distributions, probability functions, regression analysis (forecasting specially adapted for a specific administrative, business or logistic context G06Q10/04)} · CPC title

• G06K5/00

  Methods or arrangements for verifying the correctness of markings on a record carrier; Column detection devices · CPC title

• G06Q10/06395

  Quality analysis or management · CPC title

• G06Q10/0875

  Itemisation or classification of parts, supplies or services, e.g. bill of materials · CPC title