Handheld Lumber Board Counting via Homographic Transformation

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Solution Overview

Problem

Existing automated systems for counting lumber boards using cameras are expensive, require controlled environments, and are inefficient due to variations in illumination, viewpoint, and board texture, making them unsuitable for handheld devices.

Innovation Solution

A handheld device with image processing capabilities applies homographic transformations and edge detection algorithms to estimate a frontal view of a bundle of boards, allowing for automatic counting and measurement without the need for precise positioning or controlled lighting, using a reference object to aid in perspective correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fixed mounting systems with controlled illumination are used, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveboard counting accuracyVSAvoidsystem configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical fixed mounting system with a handheld mobile device that uses computational photography and image processing algorithms to achieve accurate board counting and measurement without requiring controlled illumination or precise positioning

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the approach from controlling physical parameters (illumination, camera position) to using software-based parameter adjustment through image processing algorithms that can compensate for variations in lighting conditions and viewing angles

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If fixed cameras with controlled environments are used, then measurement precision is improved, but productivity decreases

Engineering Contradiction:

Improveboard measurement accuracyVSAvoidtime to position and image boards

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system transitions from a static fixed camera system to a dynamic handheld device that can move freely and capture images of boards in their existing positions, eliminating the time required to position boards in front of a fixed camera

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The handheld device with automated image processing performs the measurement task independently without requiring operators to manually position boards or adjust lighting conditions, thereby increasing productivity

Inventive Principle:

Principle #25Self-service

3Productivity

If handheld devices are used, then productivity is improved, but measurement precision deteriorates due to image variations

Engineering Contradiction:

Improvemobile counting efficiencyVSAvoidautomated analysis accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces image processing algorithms and computational photography techniques as intermediaries between the handheld camera and the board counting task, these intermediaries process and normalize images to compensate for variations in illumination, viewpoint, and scale

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system creates a processed digital copy of the board image that corrects for perspective distortion and lighting variations, allowing accurate measurement to be performed on the processed copy rather than the raw captured image

Inventive Principle:

Principle #26Copying

4Measurement precision

If existing automated systems are used, then measurement precision is improved, but loss of time increases due to positioning requirements

Engineering Contradiction:

Improveautomated board counting accuracyVSAvoidtime to position boards for imaging

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The handheld device performs measurements directly at the board location without requiring preliminary positioning actions, capturing images of boards in their existing positions and using image processing to achieve accurate measurements

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11216905B2Automatic detection, counting, and measurement of lumber boards using a handheld device

Publication Date: 2022.01.04 FORDAQ SA

AI summary

An image processing system receives an image depicting a bundle of boards. The bundle of boards has a front face that is perpendicular to a long axis of boards and the image is captured at an angle relative to the long axis. The image processing system applies a homographic transformation to estimate a frontal view of the front face and identifies a plurality of divisions between rows in the estimate. For each adjacent pair of the plurality of divisions between rows, a plurality of vertical divisions is identified. The image processing system identifies a set of bounding boxes defined by pairs of adjacent divisions between rows and pairs of adjacent vertical divisions. The image processing system may filter and/or merge some bounding boxes to better match the bounding boxes to individual boards. Based on the bounding boxes, the image processing system determines the number of boards in the bundle.