Evaluation of imaging in automated visual web inspection

Dissertation

Laitinen Jyrki

Research output: ThesisDissertationMonograph

Abstract

In this research methods for the evaluation of the imaging in automated visual web inspection are presented. In web inspection a flat object is moving in the field of view of the sensor in such a way that an image can be formed by synchronizing the image formation and the web movement. Examples of web-like objects are metal, paper, textile and plastic strips or sheets and wooden boards or planks. The research concentrates on the evaluation of a CCD or TDI line scan based imaging unit. An imaging unit will be treated as a system consisting of imaging optics, camera, digitization electronics and mechanical and other accessories. Several methods for the quantification of the properties of an imaging unit are introduced. These include a method for the determination of the system modulation transfer function and for the determination of the system noise characteristics. In addition, the determination of the response linearity and uniformity across the image area is discussed in the context of the system dynamic range. The properties of the exemplary systems are derived in most cases from digitized test image data. Light sources and illumination arrangements are considered only if they affect on the quality of imaging. It is assumed that light sources used in practical CCD or TDI line scan based inspection are incoherent and polychromatic. The main objective of the research is to demonstrate that the performance of an imaging unit of a web inspection system can be characterized with a few figures of merit which can be used for systematic evaluation and design of imaging in web inspection applications. Application-specific examples of the systematic evaluation of imaging in web inspection are given.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • University of Oulu
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5350-0
Publication statusPublished - 1998
MoE publication typeG4 Doctoral dissertation (monograph)

Fingerprint

inspection
evaluation
strip
charge coupled devices
light sources
metal strips
accessories
textiles
modulation transfer function
figure of merit
field of view
dynamic range
linearity
plastics
illumination
cameras
optics
sensors
electronics

Keywords

  • imaging units
  • image scanning
  • image acquisition
  • charge coupled device
  • web inspection
  • paper inspection
  • metal inspection

Cite this

Jyrki, L. (1998). Evaluation of imaging in automated visual web inspection: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Jyrki, Laitinen. / Evaluation of imaging in automated visual web inspection : Dissertation. Espoo : VTT Technical Research Centre of Finland, 1998. 180 p.
@phdthesis{26bcedd361504c87bd906be8a26e54d1,
title = "Evaluation of imaging in automated visual web inspection: Dissertation",
abstract = "In this research methods for the evaluation of the imaging in automated visual web inspection are presented. In web inspection a flat object is moving in the field of view of the sensor in such a way that an image can be formed by synchronizing the image formation and the web movement. Examples of web-like objects are metal, paper, textile and plastic strips or sheets and wooden boards or planks. The research concentrates on the evaluation of a CCD or TDI line scan based imaging unit. An imaging unit will be treated as a system consisting of imaging optics, camera, digitization electronics and mechanical and other accessories. Several methods for the quantification of the properties of an imaging unit are introduced. These include a method for the determination of the system modulation transfer function and for the determination of the system noise characteristics. In addition, the determination of the response linearity and uniformity across the image area is discussed in the context of the system dynamic range. The properties of the exemplary systems are derived in most cases from digitized test image data. Light sources and illumination arrangements are considered only if they affect on the quality of imaging. It is assumed that light sources used in practical CCD or TDI line scan based inspection are incoherent and polychromatic. The main objective of the research is to demonstrate that the performance of an imaging unit of a web inspection system can be characterized with a few figures of merit which can be used for systematic evaluation and design of imaging in web inspection applications. Application-specific examples of the systematic evaluation of imaging in web inspection are given.",
keywords = "imaging units, image scanning, image acquisition, charge coupled device, web inspection, paper inspection, metal inspection",
author = "Laitinen Jyrki",
note = "Project code: E5SU00153",
year = "1998",
language = "English",
isbn = "951-38-5350-0",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "370",
address = "Finland",
school = "University of Oulu",

}

Jyrki, L 1998, 'Evaluation of imaging in automated visual web inspection: Dissertation', Doctor Degree, University of Oulu, Espoo.

Evaluation of imaging in automated visual web inspection : Dissertation. / Jyrki, Laitinen.

Espoo : VTT Technical Research Centre of Finland, 1998. 180 p.

Research output: ThesisDissertationMonograph

TY - THES

T1 - Evaluation of imaging in automated visual web inspection

T2 - Dissertation

AU - Jyrki, Laitinen

N1 - Project code: E5SU00153

PY - 1998

Y1 - 1998

N2 - In this research methods for the evaluation of the imaging in automated visual web inspection are presented. In web inspection a flat object is moving in the field of view of the sensor in such a way that an image can be formed by synchronizing the image formation and the web movement. Examples of web-like objects are metal, paper, textile and plastic strips or sheets and wooden boards or planks. The research concentrates on the evaluation of a CCD or TDI line scan based imaging unit. An imaging unit will be treated as a system consisting of imaging optics, camera, digitization electronics and mechanical and other accessories. Several methods for the quantification of the properties of an imaging unit are introduced. These include a method for the determination of the system modulation transfer function and for the determination of the system noise characteristics. In addition, the determination of the response linearity and uniformity across the image area is discussed in the context of the system dynamic range. The properties of the exemplary systems are derived in most cases from digitized test image data. Light sources and illumination arrangements are considered only if they affect on the quality of imaging. It is assumed that light sources used in practical CCD or TDI line scan based inspection are incoherent and polychromatic. The main objective of the research is to demonstrate that the performance of an imaging unit of a web inspection system can be characterized with a few figures of merit which can be used for systematic evaluation and design of imaging in web inspection applications. Application-specific examples of the systematic evaluation of imaging in web inspection are given.

AB - In this research methods for the evaluation of the imaging in automated visual web inspection are presented. In web inspection a flat object is moving in the field of view of the sensor in such a way that an image can be formed by synchronizing the image formation and the web movement. Examples of web-like objects are metal, paper, textile and plastic strips or sheets and wooden boards or planks. The research concentrates on the evaluation of a CCD or TDI line scan based imaging unit. An imaging unit will be treated as a system consisting of imaging optics, camera, digitization electronics and mechanical and other accessories. Several methods for the quantification of the properties of an imaging unit are introduced. These include a method for the determination of the system modulation transfer function and for the determination of the system noise characteristics. In addition, the determination of the response linearity and uniformity across the image area is discussed in the context of the system dynamic range. The properties of the exemplary systems are derived in most cases from digitized test image data. Light sources and illumination arrangements are considered only if they affect on the quality of imaging. It is assumed that light sources used in practical CCD or TDI line scan based inspection are incoherent and polychromatic. The main objective of the research is to demonstrate that the performance of an imaging unit of a web inspection system can be characterized with a few figures of merit which can be used for systematic evaluation and design of imaging in web inspection applications. Application-specific examples of the systematic evaluation of imaging in web inspection are given.

KW - imaging units

KW - image scanning

KW - image acquisition

KW - charge coupled device

KW - web inspection

KW - paper inspection

KW - metal inspection

M3 - Dissertation

SN - 951-38-5350-0

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Jyrki L. Evaluation of imaging in automated visual web inspection: Dissertation. Espoo: VTT Technical Research Centre of Finland, 1998. 180 p.