Image restoration from vibrating photographic systems

Zalevsky, Zeev; Raveh, Ido; Mendlovic, David; Lohmann, Adolf W.

doi:10.1364/ao.38.006205

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…The prospect of controlled blurring for dose painting would greatly simplify the delivery analysis, allowing for a linear systems theory approach as is done with imaging (Stern and Kopeika 1999, Zalevsky et al 1999). The extent to which the moving compensator approximation used in Bortfeld et al (2002) is a valid description for dynamic IMRT with motion, and the extent that one is well away from the interference maxima, is also the extent to which a simple blurring transfer-function of the motion can be used for the whole delivery as was done for HT for the arc motion of a single beamlet about a projection (Kissick et al 2007).…”

Section: Discussionmentioning

confidence: 99%

A phantom model demonstration of tomotherapy dose painting delivery, including managed respiratory motion without motion management

Kissick¹,

Mo²,

McCall³

et al. 2010

Phys. Med. Biol.

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Purpose-To demonstrate a potential alternative scenario for accurate dose painting (nonhomogeneous planned dose) delivery at the 1 cm beam width with helical tomotherapy (HT) in the presence of 1 cm, three dimensional, intra-fraction respiratory motion, but without any active motion management.Method and Materials-A model dose painting experiment was planned and delivered to the average position (proper phase of a 4DCT scan) with three spherical PTV levels to approximate dose painting to compensate for hypothetical hypoxia in a model lung tumor. Realistic but regular motion was produced with the Washington University 4D Motion Phantom. A small spherical Virtual Water™ phantom was used to simulate a moving lung tumor inside of the LUNGMAN™ anthropomorphic chest phantom to simulate realistic heterogeneity uncertainties. A piece of 4 cm Gafchromatic EBT™ film was inserted into the 6 cm diameter sphere. The TomoTherapy, Inc. DQA™ software was used to verify the delivery performed on a TomoTherapy Hi-Art II™ device.Results-The dose uncertainty in the purposeful absence of motion management and in the absence of large, low frequency drifts (periods greater than the beam width divided by the couch velocity) or randomness in the breathing displacement yields very favorable results. Instead of interference effects, only small blurring is observed because of the averaging of many breathing cycles and beamlets and the avoidance of interference.Conclusion-Dose painting during respiration with helical tomotherapy is feasible in certain situations without motion management. A simple recommendation is to make respiration as regular as possible without low frequency drifting. The blurring is just small enough to suggest that it may be acceptable to deliver without motion management if the motion is equal to the beam width or smaller (at respiration frequencies) when registered to the average position.

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Section: Discussionmentioning

confidence: 99%

A phantom model demonstration of tomotherapy dose painting delivery, including managed respiratory motion without motion management

Kissick¹,

Mo²,

McCall³

et al. 2010

Phys. Med. Biol.

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“…As described in Ref. 4 and as is explained in Sec. 3, a blocked temporal readout process is effective in expanding the spectral bandwidth of the vibration blurring function.…”

Section: Suggested Approachmentioning

confidence: 98%

“…2,3 Another approach is based on finding the zero-crossing of the captured spatial spectrum to determine the vibration parameters. 4 Other vibration restoration algorithms are iterative methods. One iterative algorithm is based on the method of projection onto convex sets ͑POCS͒.…”

Section: Introductionmentioning

confidence: 99%

Temporally masked camera readout technique for obtaining an invariance to platform vibration distortions

2005

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Vibration distortions cause the major problems faced by various imaging sensors placed on automated platforms. The nature of those vibrations is expressed in distortion of high spatial frequencies existing in the captured image. Such distortions are caused by the movements of the camera (or the object) during the integration time of the detector. We suggest a temporally masked time integrating readout process that results in enhancement of the captured spatial frequencies.The enhancement requires some digital processing operations. The suggested temporally blocked readout process is expressed by blocking the integration at predetermined times. Since the integration block periods are very short, the suggested technique is energetically efficient. © 2005 Society of Photo-Optical Instrumentation Engineers.

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Modeling possible defocus and vibration distortions of infra-red images

Zalevsky

21st IEEE Convention of the Electrical and Electronic Engineers in Israel. Proceedings (Cat. No.00EX377)

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Image restoration from vibrating photographic systems

Cited by 4 publications

References 10 publications

A phantom model demonstration of tomotherapy dose painting delivery, including managed respiratory motion without motion management

A phantom model demonstration of tomotherapy dose painting delivery, including managed respiratory motion without motion management

Temporally masked camera readout technique for obtaining an invariance to platform vibration distortions

Modeling possible defocus and vibration distortions of infra-red images

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