Print Inspection Image Grouping for Real-Time Defect Detection

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Solution Overview

Problem

Existing digital printers face challenges in achieving real-time inspection of print quality during production, particularly in roll label printing, due to the need for resource-intensive image comparisons across multiple pages, leading to prolonged inspection times and inefficiencies.

Innovation Solution

An inspection apparatus and system that groups pages into inspection units, generates sample images, and performs collective inspections using a GPU to reduce the number of resource-intensive comparisons, enabling real-time defect detection before the print is completed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If inspection time is reduced to achieve real-time inspection, then productivity is improved, but measurement precision may deteriorate

Engineering Contradiction:
Improveinspection speedVSAvoidimage comparison accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent generates sample images in advance from RIP data before actual printing occurs. These pre-generated sample images are stored and ready for immediate comparison with inspection images during printing, eliminating the need to generate sample images in real-time and thus reducing inspection time while maintaining comparison accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional CPU-based image processing with GPU-based parallel processing. The GPU accelerates the computationally intensive image comparison operations between sample images and inspection images, enabling real-time inspection without compromising measurement precision

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

2Manufacturing precision

If multiple copies are inspected with defect inspection program, then manufacturing precision is improved, but loss of time increases

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidinspection time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

Sample images for multiple copies are generated in advance from the RIP data before printing begins. This preliminary generation allows the inspection system to have all reference images ready simultaneously, enabling parallel or rapid sequential comparison with inspection images from multiple copies without delaying the inspection process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inspection system continuously compares inspection images against pre-generated sample images as prints are produced. The GPU maintains continuous processing operations, ensuring that inspection of multiple copies occurs without interruption or idle time, thereby reducing total inspection time while maintaining defect detection accuracy

Inventive Principle:
Principle #20Continuity of useful action

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 significantly reduces inspection time by optimizing resource usage and enabling real-time detection of defects, ensuring high-quality print production without delays.

Implementation Method 1

an image produced by scanning a print in advance or a raster image processor (RIP) image during printing is generated as a sample image

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4518304B1Inspection apparatus and inspection system
Publication Date: 2026.05.13 CANON KK
  • EP4518304B1 patent drawingFigure 1
  • EP4518304B1 patent drawingFigure 2
  • EP4518304B1 patent drawingFigure 3A~3C

AI summary

In inspection of a minimum size in a feeding direction in inspection, the inspection of the previous page is not finished before the inspection of the next page is started due to ensuring of resources, initial setup, and so on for the inspection. An inspection apparatus (200) includes receiving means (221) that receives a first image, registration means (223) that generates a second image in which multiple first images are continuously arranged based on the first image if the received first image meets a predetermined condition to register the second image as a sample image, a reader (225) that reads a read image, and inspection means (223) that inspects a print based on the sample image and the read image read by the reader from the print resulting from formation of an image on a sheet by image formation means.