Biomedical Engineering Reference
In-Depth Information
7
Overview of
Adaptive Optics in
Biological Imaging
7.1.
Biological.Imaging.and.Adaptive.Optics.........................................95
Elijah Y. S. Yew
Singapore-MIT Alliance
for Research and
Technology (SMART)
7.2.
Biological.Imaging.in.the.Eye............................................................98
Tomography. •.
Multiconjugate.Adaptive.Optics.for.Wide.Field.of.View
7.3.
Biological.Imaging.with.Microscopes............................................ 101
Peter T. C. So
Massachusetts Institute
of Technology
7.4.
Conclusion..........................................................................................104
7.1 Biological imaging and Adaptive optics
he. problem. of. biological. imaging,. like. all. other. imaging. problems,. is. the. formation. of. an. image.
that.is.as.close.as.possible.to.the.original.object..Like.all.other.imaging.problems,.the.image.quality.
depends.very.much.on.the.quality.of.the.optics,.the.assembly,.the.imaging.medium,.and.the.object.
itself..While.modern-day.optics.are.close.to.being.perfect,.oten.the.sources.of.aberrations.lie.in.the.
assembly,.such.as.in.custom-built.imaging.systems;.the.imaging.medium,.such.as.the.turbulent.atmo-
sphere.in.astronomy;.and.the.object.itself,.such.as.in.refractive.index.heterogeneity.in.many.biologi-
cal. specimens.. he. way. in. which. imaging. quality. is. restored. under. such. circumstances. is. through.
the.use.of.adaptive.optics.(AO),.a.ield.that.is.relatively.established.in.astronomy..he.use.of.adaptive.
optics.has.been.applied.to.biological.imaging,.in.particular.the.eye,.as.early.as.1989.[1],.although.it.
really.took.of.with.the.implementation.of.the.Shack-Hartmann.wavefront.sensor.(SHWS).to.form.a.
feedback.loop.for.active.correction.[2].
he.various.parts.of.an.AO.system.consist.primarily.of.a.wavefront.sensing.device,.an.active.wave-
front.shaping.element,.a.controller.that.links.the.sensing.device.to.the.active.element,.and.the.feedback.
to.monitor.the.image.quality.
7.1.1 Wavefront Sensing
he. detection. of. aberrations. is. important. since. with. that. information. the. active. element. of. the. AO.
system.can.implement.the.appropriate.corrections.to.the.deformation.to.compensate.for.the.detected.
aberrations.. However,. the. detection. of. aberrations. need. not. be. limited. to. AO. systems. as. the. image.
.quality.of.the.fundus.of.an.aberrated.eye.needs.to.be.determined.accurately.for.a.corrective.surgery.to.
be.successful.
95