Universiti Teknologi Malaysia Institutional Repository

Measurement of wiener spectrum of radiographic screen-film systems

Wan Hassan, Wan Muhamad Saridan (2001) Measurement of wiener spectrum of radiographic screen-film systems. Jurnal Teknologi C (34C). pp. 35-42. ISSN 0127-9696


Official URL: http://www.penerbit.utm.my/onlinejournal/34/C/JT34...


A method to measure the Wiener spectrum of radiographic screen-film systems in a hospital setting is presented. Radiographs exposed to uniform X-rays are scanned by a microdensitometer, and optical density fluctuation data about the mean density are obtained by subtracting the mean density from the density values. The data are low-pass-filtered by averaging pairs of pixels, followed by low-frequency filtering to eliminate very low-frequency components. A slit trace is synthesised by averaging adjacent traces and the trace is segmented to segments of 256 data points per segment with overlap of 128 data points. Data in each segment are windowed and fast Fourier transformed. The Fourier coefficients are squared and normalized to obtain the power spectrum. On site measurement for Lanex Regular and Lanex Fine screens gives results that are comparable with published data.

Item Type:Article
Uncontrolled Keywords:noise power spectrum, radiography, screen-film system, Wiener spectrum
Subjects:Q Science > QC Physics
ID Code:882
Deposited By: Mohd. Nazir Md. Basri
Deposited On:22 Feb 2007 08:43
Last Modified:01 Nov 2017 04:17

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