High-resolution CMOS imaging detector

Graeve, Thorsten; Weckler, Gene P.

doi:10.1117/12.430886

Cited by 50 publications

(34 citation statements)

References 25 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] While many improvements have been made on the detector technology, image acquisition methods, and image display system, less attention has been paid to the long recognized problem of scattered x-rays in projection imaging.…”

Section: Introductionmentioning

confidence: 99%

Scatter rejection and low‐contrast performance of a slot‐scan digital chest radiography system with electronic aft‐collimation: A chest phantom study

et al. 2008

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Anti-scatter grids have been widely used to reject scatter and increase the perceptibility of lowcontrast object in chest radiography; however they also attenuate the primary x-rays, resulting in a substantial degradation of primary information. Compensation for this degradation requires the use of higher exposure technique hence higher dose to the patient. A more efficient approach to reject scatter is the slot-scan imaging technique which employs a narrow scanning x-ray fan beam in conjunction with a slit or slot shaped solid state detector or an area detector used with an aftcollimator. With this approach, scatter can be rejected effectively without the need to attenuate primary x-rays. This paper demonstrates an electronic aft-collimation method, referred to as the alternate line erasure and readout ͑ALER͒ technique, for implementing the slot-scan digital radiography with a modern flat-panel detector. With this technique, instead of first exposing the detector and then reading the image line by line, the image line on the leading edge of the scanning fan beam is reset to erase the scatter accumulated prior to the arrival of the fan beam x-rays, while the image line on the trailing edge of the scanning fan beam is read out to acquire the image signals following the fan-beam exposure. These reset and readout processes are alternated and repeated as the x-ray fan beam scans across the detector. An anthropomorphic chest phantom was imaged to evaluate the scatter rejection ability and the low-contrast performance for the ALER technique and compare them with those for the anti-scatter grid method in full-field chest imaging. With a projected beam width of 16 mm, the slot-scan/ALER technique resulted in an average reduction of the scatter-toprimary ratios by 81%, 84%, 82%, and 86% versus 65%, 73%, 74%, and 73% with the anti-scatter grid method in the lungs, mediastinum, retrocardium, and subdiaphragm, respectively. The average CNR for the slot-scan/ALER technique was found to improve by 135%, 133%, 176%, and 87% versus 15%, 15%, 38%, and −11% with the anti-scatter grid method in the mediastinum, retrocardium, subdiaphragm, and lungs, respectively. These results demonstrated that the slot-scan/ALER technique can be used to achieve equally effective scatter rejection but substantially higher lowcontrast performance than the anti-scatter grid method.

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Section: Introductionmentioning

confidence: 99%

Scatter rejection and low‐contrast performance of a slot‐scan digital chest radiography system with electronic aft‐collimation: A chest phantom study

et al. 2008

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“…The maximum frame rate of the assembled panels was 4.5 frames per second (fps). Detailed physical specifications and the electrical/optical characteristics of the CMOS APS photodiode panel used in this study are found in reference [40].…”

Section: A System Descriptionmentioning

confidence: 99%

Fourier Analysis of Noise Characteristics in Cone-Beam Microtomography Laboratory Scanners

Jang¹,

Kim

Youn³

et al. 2017

IEEE Trans. Biomed. Eng.

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“…The CMOS photodiode array (RadEye, Rad-icon Imaging Corp., CA, USA) has a format of 512 1024 pixels with a pitch of 48 m [7]. The active area is about 25 50 mm .…”

Section: A Detector Preparationmentioning

confidence: 99%

Signal and Noise Characteristics Induced by Unattenuated X Rays from a Scintillator in Indirect-Conversion CMOS Photodiode Array Detectors

Yun

Kim

Lim

et al. 2009

IEEE Trans. Nucl. Sci.

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We report the measurement results of signal and noise characteristics induced by the direct x-rays in an indirect-conversion CMOS photodiode array detector. In order to isolate the signal and noise due to the direct x-rays from those due to the optical photons, we inserted a light-absorbing blackout material between a phosphor screen and the photodiode array. From the images irradiated with and without the blackout paper, the signal and noise characteristics due to the optical photons emitted from a phosphor screen were estimated. For the analysis of the measurements, we have developed a model describing the signal and noise transfers based on the cascaded linear-systems approach. The measured results show the direct x-ray is very harmful to the detector performances, such noise power spectrum (NPS) and signal-to-noise ratio (SNR). However, from the theoretical estimation, the degradation of NPS and SNR would not be due to the directly absorbed x-ray photons, but we believe that other sources, such as Compton and photoelectric scattered rays from a scintillator, a photodiode passivation layer or bulk substrate, are main causes.Index Terms-Cascaded system analysis, image quality, noise power spectrum, radiography.

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High-resolution CMOS imaging detector

Cited by 50 publications

References 25 publications

Scatter rejection and low‐contrast performance of a slot‐scan digital chest radiography system with electronic aft‐collimation: A chest phantom study

Scatter rejection and low‐contrast performance of a slot‐scan digital chest radiography system with electronic aft‐collimation: A chest phantom study

Fourier Analysis of Noise Characteristics in Cone-Beam Microtomography Laboratory Scanners

Signal and Noise Characteristics Induced by Unattenuated X Rays from a Scintillator in Indirect-Conversion CMOS Photodiode Array Detectors

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