1 Image Quality, T.T. Liu, Spring 2006 Image Quality Lecture 2 Thomas Liu UCSD Center for Functional MRI Resident Physics Course April 3, 2006 Image Quality, T.T. Liu, Spring 2006 Topics Review MTF question Noise Receiver Operating Characteristics Sampling and Aliasing
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Image Quality, T.T. Liu, Spring 2006
Image QualityLecture 2
Thomas LiuUCSD Center for Functional MRI
Resident Physics CourseApril 3, 2006
Image Quality, T.T. Liu, Spring 2006
Topics
Review MTF question
Noise
Receiver Operating Characteristics
Sampling and Aliasing
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Image Quality, T.T. Liu, Spring 2006
MTF = Fourier Transform (LTF)
Bushberg et al 2001
Image Quality, T.T. Liu, Spring 2006
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Image Quality, T.T. Liu, Spring 2006
Noise and Image Quality
Prince and Links 2005
Bushberg et al 2001
Image Quality, T.T. Liu, Spring 2006
What is Noise?Fluctuations in either the imaging system or the objectbeing imaged.
Quantization Noise: Due to conversion from analogwaveform to digital number.
Quantum Noise: Random fluctuation in the number ofphotons emitted and recorded.
Thermal Noise: Random fluctuations present in allelectronic systems. Also, sample noise in MRI
Other types: flicker, burst, avalanche - observed insemiconductor devices.