Correction of collimator aperture using a shift-variant deconvolution filter in gamma camera emission ct

Koichi Ogawa, Seungkuen Paek, Masato Nakajima, Shinichi Yuta, Atsushi Kubo, Shozo Hashimoto

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We propose a new method which enables improved spatial resolution of a reconstructed image from a gamma camera emission CT(SPECT). SPECT images are blurred due to the effect of the collimator aperture. The blur effect changes with the geometrical structure of the collimator and with the distance between the rotational center of the gamma camera and the collimator surface. The acquired projection, affected by the collimator aperture, can be assumed to be the convolution of the ideal projection by the shift-variant blur functions. So the measured projection will be represented as a weighted summation of neighboring ideal projections of different angles and positions. From this standpoint, the blur function can be defined as a function of a common spatial frequency in the Fourier domain. Hence the deconvolution of the measured projection was circularly processed in the frequency domain. The effectiveness of the method was proven by simulations involving various aperture angles and the distances between the collimator surface and the rotational center.

Original languageEnglish
Pages (from-to)699-706
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume914
DOIs
Publication statusPublished - 1988 Jun 27
Externally publishedYes

Fingerprint

Deconvolution
collimators
apertures
projection
Cameras
cameras
filters
shift
Convolution
convolution integrals
spatial resolution
simulation

ASJC Scopus subject areas

  • Applied Mathematics
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Computer Science Applications

Cite this

Correction of collimator aperture using a shift-variant deconvolution filter in gamma camera emission ct. / Ogawa, Koichi; Paek, Seungkuen; Nakajima, Masato; Yuta, Shinichi; Kubo, Atsushi; Hashimoto, Shozo.

In: Proceedings of SPIE - The International Society for Optical Engineering, Vol. 914, 27.06.1988, p. 699-706.

Research output: Contribution to journalArticle

Ogawa, Koichi ; Paek, Seungkuen ; Nakajima, Masato ; Yuta, Shinichi ; Kubo, Atsushi ; Hashimoto, Shozo. / Correction of collimator aperture using a shift-variant deconvolution filter in gamma camera emission ct. In: Proceedings of SPIE - The International Society for Optical Engineering. 1988 ; Vol. 914. pp. 699-706.
@article{5eeaf3dda73e44779ee646931e919c82,
title = "Correction of collimator aperture using a shift-variant deconvolution filter in gamma camera emission ct",
abstract = "We propose a new method which enables improved spatial resolution of a reconstructed image from a gamma camera emission CT(SPECT). SPECT images are blurred due to the effect of the collimator aperture. The blur effect changes with the geometrical structure of the collimator and with the distance between the rotational center of the gamma camera and the collimator surface. The acquired projection, affected by the collimator aperture, can be assumed to be the convolution of the ideal projection by the shift-variant blur functions. So the measured projection will be represented as a weighted summation of neighboring ideal projections of different angles and positions. From this standpoint, the blur function can be defined as a function of a common spatial frequency in the Fourier domain. Hence the deconvolution of the measured projection was circularly processed in the frequency domain. The effectiveness of the method was proven by simulations involving various aperture angles and the distances between the collimator surface and the rotational center.",
author = "Koichi Ogawa and Seungkuen Paek and Masato Nakajima and Shinichi Yuta and Atsushi Kubo and Shozo Hashimoto",
year = "1988",
month = "6",
day = "27",
doi = "10.1117/12.968702",
language = "English",
volume = "914",
pages = "699--706",
journal = "Proceedings of SPIE - The International Society for Optical Engineering",
issn = "0277-786X",
publisher = "SPIE",

}

TY - JOUR

T1 - Correction of collimator aperture using a shift-variant deconvolution filter in gamma camera emission ct

AU - Ogawa, Koichi

AU - Paek, Seungkuen

AU - Nakajima, Masato

AU - Yuta, Shinichi

AU - Kubo, Atsushi

AU - Hashimoto, Shozo

PY - 1988/6/27

Y1 - 1988/6/27

N2 - We propose a new method which enables improved spatial resolution of a reconstructed image from a gamma camera emission CT(SPECT). SPECT images are blurred due to the effect of the collimator aperture. The blur effect changes with the geometrical structure of the collimator and with the distance between the rotational center of the gamma camera and the collimator surface. The acquired projection, affected by the collimator aperture, can be assumed to be the convolution of the ideal projection by the shift-variant blur functions. So the measured projection will be represented as a weighted summation of neighboring ideal projections of different angles and positions. From this standpoint, the blur function can be defined as a function of a common spatial frequency in the Fourier domain. Hence the deconvolution of the measured projection was circularly processed in the frequency domain. The effectiveness of the method was proven by simulations involving various aperture angles and the distances between the collimator surface and the rotational center.

AB - We propose a new method which enables improved spatial resolution of a reconstructed image from a gamma camera emission CT(SPECT). SPECT images are blurred due to the effect of the collimator aperture. The blur effect changes with the geometrical structure of the collimator and with the distance between the rotational center of the gamma camera and the collimator surface. The acquired projection, affected by the collimator aperture, can be assumed to be the convolution of the ideal projection by the shift-variant blur functions. So the measured projection will be represented as a weighted summation of neighboring ideal projections of different angles and positions. From this standpoint, the blur function can be defined as a function of a common spatial frequency in the Fourier domain. Hence the deconvolution of the measured projection was circularly processed in the frequency domain. The effectiveness of the method was proven by simulations involving various aperture angles and the distances between the collimator surface and the rotational center.

UR - http://www.scopus.com/inward/record.url?scp=84957476659&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84957476659&partnerID=8YFLogxK

U2 - 10.1117/12.968702

DO - 10.1117/12.968702

M3 - Article

AN - SCOPUS:84957476659

VL - 914

SP - 699

EP - 706

JO - Proceedings of SPIE - The International Society for Optical Engineering

JF - Proceedings of SPIE - The International Society for Optical Engineering

SN - 0277-786X

ER -