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From Wednesday, 9 November 2011 the weekly lectures will be every Wednesday, 8:30 Humboldtstr. 8, Seminar Room 3 (SR 3). 2. Contrast modes in light microscopy: Bright field. Blackboard exercises: Coherent vs. Incoherent imaging. The Concept of a A mplitude S pread F unction.
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From Wednesday, 9 November 2011 the weekly lectures will beevery Wednesday, 8:30 Humboldtstr. 8, Seminar Room 3 (SR 3)
2. Contrast modes in light microscopy: Bright field Blackboard exercises:Coherent vs. Incoherent imaging The Concept of a Amplitude Spread Function Image Field as a Convolution of Object with ASF The Concept of a Point Spread Function Imaging as a Convolution of Object with PSF
Spatial Frequencies and Fourier Transforms Realspace: Intensity x [m] Fourier space: Amplitude k [1/m]
from:http://www-groups.dcs.st-and.ac.uk/ ~history/PictDisplay/Fourier.html Even better approximation: from:http://members.nbci.com/imehlmir/ Fourier Analysis
Cosine transform Fourier transform
ky ky kx kx Constructing images from waves CorrespondingSine-Wave SpatialFrequency AccumulatedFrequencies SumofWaves
Constructing images from waves CorrespondingSine-Wave SpatialFrequency AccumulatedFrequencies SumofWaves
Real Space (PSF) Reciprocal Space (ATF) Lens Cover Glass ky y x kx Focus z kz Oil Intensity in Focus (PSF)
McCutchen generalised aperture Ewald sphere
IFT A(k) a(r)
a(r) |a|2(r)
IFT A(k) a(r) |.|2 ? ? |a|2(r) FT
? Fourier Transform ~ ~ ~* I(k) = A(k) A(-k) OTF ATF Epifluorescent PSF I(x) = |A(x)|2 = A(x) · A(x)*
Region of Support kx,y kz Convolution: Drawing with a Brush
! kx,y kz Optical Transfer Function (OTF)
Objective Lense Tube Lense CCD Back FocalPlane 2. Contrast modes in light microscopy: Bright field Scattering / Absorbtion Bright FieldTransmission Dark object on bight backgroundRelative scattering angle and wavelength defines resolutionCondensor AND objective Numerical Aperture matterContrast decreases when resolution increases
kout Kobj kin 2. Contrast modes in light microscopy: Bright field Interference of diffracted lightwith the undiffracted reference (first Born approx.) Range ofDetection Angles "Bragg condition" Holgraphy with plane wave illumination: infinitely little 3D information is acquired!
2. Contrast modes in light microscopy: Bright field 1.? 2.? 3.? 6.? 4.? 5.? http://biology.about.com