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Lensless Imaging Systems: Pinhole Optics
- Pinhole optics
focuses images
- without lens
- with infinite
depth of field
- Smaller the
pinhole
- better the focus
- less light energy
1 3 Lensless Imaging Systems: Pinhole Optics Pinhole optics - - PDF document
1 3 Lensless Imaging Systems: Pinhole Optics Pinhole optics - - PDF document
1 2 1 3 Lensless Imaging Systems: Pinhole Optics Pinhole optics focuses images without lens with infinite depth of field Smaller the pinhole better the focus less light energy from any single point 4 2
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Diffraction and Pinhole Optics
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Diffraction
- Two disadvantages to pinhole systems
- Light collecting power
- Diffraction
- Diffraction
- When light passes through a small aperture it does not travel in a straight
line
- It is scattered in many directions
- Process is called diffraction and is a quantum effect
- Human vision
- At high light levels, pupil (aperture) is small and blurring is due to
diffraction
- At low light levels, pupil is open and blurring is due to lens imperfections
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The Human Eye
- Limitations of human
vision
- the image is upside-
down!
- high resolution vision
- nly in the fovea
- only one small fovea in
man
- other animals (birds,
cheetas) have different foveal organizations
- blind spot
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Color Cameras
- Two types of color cameras
- three built in filters
- three images are collected through red, green and blue filters
- such cameras are 3x slower than comparable black and white
cameras
- 3 CCD arrays packed together, each sensitive to
different wavelengths of light
- more similar to human vision
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