Multi-Focus Vision Imaging for Faster Auto-Focus Inspection

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Solution Overview

Problem

Existing auto-focus systems in machine vision processes are too slow for high-speed applications and costly for range finding systems, with hunting systems requiring excessive time and range finding systems necessitating additional hardware.

Innovation Solution

Utilizing a fast processor to obtain and process multiple images in parallel at different focus positions, allowing for rapid image acquisition and processing, including decoding or feature identification, without additional hardware costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If hunting auto-focus systems are used to obtain clear images, then image quality is improved, but the time required for the vision process increases significantly

Engineering Contradiction:
Improveimage qualityVSAvoidtime required for vision process
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by obtaining multiple images at different focus positions simultaneously and in parallel before the vision process begins. The processor obtains images at multiple focus positions (near, middle, far) concurrently, so that when the vision process needs to start, all necessary images are already available for immediate processing, eliminating the sequential time delay of traditional hunting systems.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system transitions from a single-dimension sequential approach (one focus position at a time) to a multi-dimensional parallel approach by obtaining images at multiple focus positions simultaneously. This dimensional expansion allows the system to process multiple focus scenarios concurrently, reducing overall processing time while maintaining image quality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Speed

If range finding systems are used to reduce focusing time, then speed is improved, but system cost increases due to additional hardware

Engineering Contradiction:
Improvefocusing speedVSAvoidsystem cost
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The system makes the existing camera sensor and processor multi-functional by using them to both capture images and perform focus determination. Instead of adding dedicated range-finding hardware, the same imaging components serve dual purposes: capturing images at different focus positions and analyzing those images to determine optimal focus, thereby achieving fast focusing without increasing hardware complexity or cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system enables self-service by allowing the camera system to determine focus automatically through image analysis without external range-finding assistance. The processor analyzes the obtained images to determine which focus position yields the clearest image, making the system self-sufficient and eliminating the need for additional range-finding hardware.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3401833B1Fast vision system
Publication Date: 2026.03.04 COGNEX TECHNOLOGY AND INVESTMENT LLC
  • EP3401833B1 patent drawingFigure 1
  • EP3401833B1 patent drawingFigure 2
  • EP3401833B1 patent drawingFigure 3

AI summary

A method and apparatus for performing a vision process using a camera having a multi-focus lens having a lens field of view where the lens can be set at different focus positions the method comprising the steps of positioning at least one of the camera and an item to be imaged so the lens field of view is directed at the item to be imaged, obtaining a plurality of images where each image is obtained with the lens focus at a different position and after each image is obtained, attempting to perform the machine vision process using the image irrespective of whether or not the lens was focused when the image was obtained.