&lt;title&gt;Suitability of the Pulnix TM6CN CCD camera for photogrammetric measurement&lt;/title&gt;

Robson, Stuart; Clarke, Timothy A.; Chen, Jin

doi:10.1117/12.162137

Cited by 18 publications

(17 citation statements)

References 3 publications

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“…4 In this paper one MiT measurement result from the reference6 is reviewed to demonstrate the dependence of the system MTF on the aperture of the imaging lens. This is seen in figure 3, where MTF curves for the imaging set-up described above are shown as a function of the f-number of the lens.…”

Section: Mtf Of An Imaging Set-upmentioning

confidence: 99%

<title>MTF as a figure of merit in visual surface inspection</title>

Laitinen

Moring

1996

SPIE Proceedings

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The quality of the image is crucial for the performance of a visual surface inspection system. The final image quality is affected by the properties of the illumination and imaging units. In order to evaluate the quality of these units a designer should be able to characterize their performance using quantitative figures of merit.In this paper the suitability of the modulation transfer function (MTF) for the figure of merit in visual web inspection is considered. An uncomplicated test set-up for measuring the system MTF of an imaging unit is presented and MTFs of typical web inspection imaging arrangements are introduced as a function of the f-number of the imaging lens. An appropriate set of defective samples from a paper manufacturing process is collected and imaged using the same arrangements as in the MiT measurements. Defect contrasts and signal-to-noise ratios are determined from the images and the results are compared to the corresponding MiT values.The objective of the study is to demonstrate the relationship between the MiT and the capability of inspection system to detect certain kinds of surface defects. The existence of this relationship is a necessity when MiT is considered as a figure of merit. Based on the experimental results surface defects are classified in two categories: 1 . Defects whose detectivity is critically dependent on the MiT and 2. defects whose detectivity is practically independent of the MiT. As a conclusion, examples are introduced on how the MiT measurement can be used as an imaging system evaluation and design tool.

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Section: Mtf Of An Imaging Set-upmentioning

confidence: 99%

<title>MTF as a figure of merit in visual surface inspection</title>

Laitinen

Moring

1996

SPIE Proceedings

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“…There have been many tests of image space precision of target centring algorithms. Chosen test methods vary from single target monitoring (Robson et al, 1993) to multistation convergent networks comprising many targets (Shortis, Clarke and Robson, 1995). The consensus is that centroid type algorithms can realize object space precisions equivalent to ϩ Ϫ 0·02 to 0·03 pixels.…”

Section: Reported Retrotargeting System Performancementioning

confidence: 99%

Practical Influences of Geometric and Radiometric Image Quality Provided By Different Digital Camera Systems

Robson

Shortis

1998

The Photogrammetric Record

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Imaging systems founded on current digital camera technology are finding widespread use in high precision measurement applications. A single digital CCD camera, or an array of such cameras, equipped with ring lighting equipment is commonly used to acquire imagery of high contrast retroreflective targets placed on the object at discrete locations to signalize points of interest. The precise and accurate measurement of each imaged target location is a fundamental requirement if suitable measurement tolerances are to be obtained. Whilst such systems are undoubtedly capable of producing excellent results, the practical effects of target image quality on the photogrammetric measurement process is in need of careful consideration. This paper revisits some fundamentals of the optical imaging of retrotargets and investigates some abilities of a range of digital camera systems to provide images of retrotargets that are appropriate to the measurement process. Some experimental results are presented including the imaging of planar arrays of differing sized retrotargets at differing angles and exposures and a series of network analyses in which the level of target image intensity has been varied systematically.

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“…Warm up effects in CCD imagers are well known and have been repeatedly documented since the introduction of 'solid state' cameras (Dähler, 1987;Robson et al, 1993). As the sensor and the camera as a whole progress toward temperature equilibrium after power up, the output image will drift due to thermal expansion and drift in the on-board electronics.…”

Section: Camera Warm-up Effectsmentioning

confidence: 99%

Close Range Calibration of Long Focal Length Lenses in a Changing Environment

Robson

MacDonald

Kyle

et al. 2016

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:University College London is currently developing a large-scale multi-camera system for dimensional control tasks in manufacturing, including part machining, assembly and tracking, as part of the Light Controlled Factory project funded by the UK Engineering and Physical Science Research Council. In parallel, as part of the EU LUMINAR project funded by the European Association of National Metrology Institutes, refraction models of the atmosphere in factory environments are being developed with the intent of modelling and eliminating the effects of temperature and other variations. The accuracy requirements for both projects are extremely demanding, so accordingly improvements in the modelling of both camera imaging and the measurement environment are essential. At the junction of these two projects lies close range camera calibration. The accurate and reliable calibration of cameras across a realistic range of atmospheric conditions in the factory environment is vital in order to eliminate systematic errors. This paper demonstrates the challenge of experimentally isolating environmental effects at the level of a few tens of microns. Longer lines of sight promote the use and calibration of a near perfect perspective projection from a Kern 75mm lens with maximum radial distortion of the order of 0.5m. Coordination of a reference target array, representing a manufactured part, is achieved to better than 0.1mm at a standoff of 8m. More widely, results contribute to better sensor understanding, improved mathematical modelling of factory environments and more reliable coordination of targets to 0.1mm and better over large volumes.

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<title>Suitability of the Pulnix TM6CN CCD camera for photogrammetric measurement</title>

Cited by 18 publications

References 3 publications

<title>MTF as a figure of merit in visual surface inspection</title>

<title>MTF as a figure of merit in visual surface inspection</title>

Practical Influences of Geometric and Radiometric Image Quality Provided By Different Digital Camera Systems

Close Range Calibration of Long Focal Length Lenses in a Changing Environment

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