Image Measuring Apparatus Noise Reduction Edge Detection

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Solution Overview

Problem

Image measuring apparatuses face challenges in performing dimensional and form measurements due to noise in images, leading to inaccurate edge point detection and measurement precision issues.

Innovation Solution

The apparatus employs an imaging device and a processing device that generates a lower-resolution image pyramid, segments the image into regions, performs edge detection, and removes outliers to enhance measurement accuracy by reducing noise, with a control program recorded on a non-temporary medium to control these processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If image processing is performed on high-resolution images to improve measurement precision, then measurement precision improves, but processing time and computational load increase

Engineering Contradiction:
Improveedge point detection precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The image processing is divided into multiple resolution levels (pyramid structure). Coarse processing is performed on down-sampled lower-resolution images to identify candidate regions, while fine processing is applied only to specific regions of interest in the original high-resolution image. This segmentation of processing across different scales reduces overall computational load while maintaining measurement precision for critical features.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If noise filtering is applied to reduce measurement errors, then measurement precision improves, but edge point detection accuracy may deteriorate due to over-smoothing

Engineering Contradiction:
Improvedimensional measurement accuracyVSAvoidedge point detection accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

Different processing strategies are applied to different regions of the image based on their characteristics. In regions with strong edges, minimal filtering is applied to preserve edge accuracy. In homogeneous regions with noise, more aggressive filtering is applied. This local differentiation allows the system to reduce measurement errors from noise while avoiding over-smoothing that would degrade edge point detection accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The problem is solved by transitioning between different resolution dimensions. Noise filtering and candidate region identification are performed on lower-resolution images where noise has less impact. Once candidate regions are identified, precise edge detection is performed on the original high-resolution image, leveraging the multi-dimensional (multi-resolution) approach to balance noise reduction with edge accuracy.

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

3Measurement precision

If full-resolution image processing is performed to maintain detail accuracy, then measurement precision is maintained, but processing speed decreases

Engineering Contradiction:
Improveform measurement accuracyVSAvoidprocessing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Preliminary processing steps (down-sampling, coarse filtering, candidate region identification) are performed on lower-resolution images before final high-resolution processing. This preliminary action at reduced resolution quickly eliminates non-candidate regions, so that full-resolution processing is only applied to a small subset of interesting regions, thereby maintaining measurement precision while significantly improving processing speed.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9972095B2Image measuring apparatus and non-temporary recording medium on which control program of same apparatus is recorded
Publication Date: 2018.05.15 MITUTOYO CORP
  • US9972095B2 patent drawing
  • US9972095B2 patent drawing
  • US9972095B2 patent drawing

AI summary

An image measuring apparatus according to an embodiment of the present invention comprises: an imaging device that images a workpiece to acquire an image of this workpiece; and a processing device that performs measurement of the workpiece based on this image and outputs a measurement result. Moreover, the processing device, based on the above-described image, generates another image whose number-of-pixels is smaller than that of the image, sets a plurality of regions based on this another image, and calculates the above-described measurement result based on these plurality of regions.