Analysis and improvement on sharpness evaluation function of defocused image

YU-zhen, 洪裕珍 Hong; Guo-qiang, 任国强 Ren; Jian, 孙健 Sun

doi:10.3788/ope.20142212.3401

Cited by 7 publications

(3 citation statements)

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“…Once the camera's position in relation to the calibration board is determined, the discriminant function can be used to find an appropriate focus position. In this study, the method proposed in reference [11] was employed to enhance the clarity of the images. The processing procedure is as follows:…”

Section: Fig3：calibration Board Imagesmentioning

confidence: 99%

Multi-perspective long-focus camera calibration algorithm based on parallel perspective projection model

SiYu,

Xue,

Tao

2023

AOPC 2023: Optical Sensing, Imaging, and Display Technology and Applications; And Biomedical Optics

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Section: Fig3：calibration Board Imagesmentioning

confidence: 99%

Multi-perspective long-focus camera calibration algorithm based on parallel perspective projection model

SiYu,

Xue,

Tao

2023

AOPC 2023: Optical Sensing, Imaging, and Display Technology and Applications; And Biomedical Optics

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“…The position and angle of the object or the focal length of the imaging equipment are adjusted to be clear, and the image of the object is converted to digital image information, which is transmitted to the computer for image processing. include Sobel operator, Laplacian operator, and variance evaluation function [17] .…”

Section: High Quality Image Acquisition Technology For Tool Wearmentioning

confidence: 99%

Research on online detection System of lathe tool wear based on Machine Vision

Ding

Wan

Zhang

2021

Preprint

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Machine tools are important factor to determine the surface quality of the workpiece, and the online detection of tool wear is of great significance to the production and processing. In this paper, turning tools are taken as the research object, the tool wear evaluation index is defined, and the online detection system of lathe tool wear based on machine vision is designed. The workpiece processing, tool wear image acquisition, transmission, storage, and processing are completed in this system. Aiming at the problem of tool wear state detection, an adaptive hybrid filtering method is proposed in order to remove noise in the image acquisition process, nonlinear transformation and unsharp masking methods are used to enhance tool wear image quality. The GrabCut improved algorithm is used to segment the tool wear image. The Canny edge detection operator with adaptive double thresholds is used to detect the edge of the tool wear area. Finally, the upper and lower boundaries of the tool wear area are detected by using the Hough transform method, and the wear value of the tool flank is calculated, which is compared with the blunt standard VB=06mm to determine whether the tool needs to be replaced. The accuracy of the detection method is verified by experimental measurement of the surface roughness of the workpiece after machining.

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“…Turbofan blades are core components of aircraft engines, and the measurement of their film holes is crucial to the performance and reliability of the engine. Film holes are small holes machined on the turbofan blade surface, used for film cooling during high-speed rotation [1] . Due to their small diameter and curved surface, as well as the difficulties in machining, accurate detection has always been a technical challenge in the industry.…”

Section: Introductionmentioning

confidence: 99%

Study on pixel evaluation function of air film hole image of turbine blade

Fan,

Zhang,

et al. 2024

Advanced Fiber Laser Conference (AFL2023)

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In the process of measuring the diameter of the air film holes in turbine blades, visual technology is widely used. However, the selection of a clearness evaluation method and clearness evaluation operator for the pixels in the images obtained by photography is a crucial problem. In view of the small diameter of the air film holes in turbine blades, strong reflective characteristics of the material, difficulties in obtaining a focused image of the oblique holes, and difficulties in edge extraction, a five-axis measurement system was built using a three-coordinate measuring machine and a two-axis rotary table to take a series of pictures of the air film holes in turbine blades. In terms of image processing, different clearness evaluation functions were used to test images at different focal positions, including Sobel function, Brenner function, Tenengrad function, Laplacian function, etc. By comparing and analyzing the clearness evaluation curves obtained by these functions, the most suitable clearness evaluation function was selected. In order to make the results more convincing, the selected function was normalized to ensure its evaluation results were comparable across different images. Finally, a suitable clearness evaluation function for the air film holes in turbine blades was derived and its effectiveness was verified. This achievement lays a foundation for the improvement of the Sobel operator in the future, which is helpful to improve the accuracy and stability of measuring the diameter of air film holes in turbine blades.

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Analysis and improvement on sharpness evaluation function of defocused image

Cited by 7 publications

References 0 publications

Multi-perspective long-focus camera calibration algorithm based on parallel perspective projection model

Multi-perspective long-focus camera calibration algorithm based on parallel perspective projection model

Research on online detection System of lathe tool wear based on Machine Vision

Study on pixel evaluation function of air film hole image of turbine blade

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