Columbia Technology Ventures

Diffusion-coded photography for extended depth of field

This technology is an optical diffuser that enables extended depth of field in imaging systems while maintaining a large aperture size.

Unmet Need: Imaging systems with adequate depth of field capabilities

Most conventional cameras are plagued with a fundamental trade-off between depth of field (DOF) and image noise. As most cameras have a single focal plane, any objects outside of this plane end up blurry due to defocusing. While the aperture size may be decreased to decrease defocus blur and increase DOF, this results in reducing the signal strength of the recorded image. As such, there is a need for an imaging system that enables increased DOF without a decrease in aperture size, especially for applications such as machine vision.

The Technology: Optical diffuser allows extended depth of field imaging without reducing aperture size

This technology provides a diffusion-coded imaging system that achieves the performance of a focal sweep camera without introducing artifacts or a decrease in the aperture size. This technology uses a custom optical diffuser and a depth-invariant point spread function (PSF) that enables imaging an extended depth of field without the need for depth estimation or mechanical motion. This technology could be especially useful to machine vision applications such as industrial automation, in which a large depth of field is desired.

This technology has been prototyped and demonstrated a significant extension of DOF compared with existing methods.

Applications:

  • Bar code readers with extended depth of field
  • Machine vision systems for industrial automation processes
  • Extended depth of field in cameras and other image-recording devices
  • Microscopy
  • Security/surveillance systems

Advantages:

  • Eliminates blurred zones attributed to typical depth of field limitations
  • Does not require any fundamental changes in imaging system design
  • Achieves extended depth of field without taking multiple images
  • Produces consistently high-quality images at a range of depths of focus

Lead Inventor:

Shree K. Nayar, Ph.D.

Patent Information:

Patent Issued

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