System and Method for Diffuse Imaging with Time-varying Illumination Intensity

Technology #15072

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 FIG. 1 is a perspective view of a scene with an omnidirectional light source that illuminates the scene and a 4-by-4 array of light meters for measuring the reflected light.  FIGS. 2 a and 2 b are plots illustrating that time delay from source to scene to light meter is a continuous function of the position in the scene. FIGS. 3 a and 3 b are plots showing a single measurement function according to m embodiment of the invention herein.  FIG. 4 is an illustration of an example matrix A corresponding to Light Meter 1 for the scene in FIG. 1. FIG. 5 is a block diagram abstraction for a signal sampled at Light Meter k.  FIG. 6 a is a graph of amplitude against time showing responses to impulsive illumination in FIG. 1.  FIG. 6 b is another graph of amplitude against time showing continuous time responses. FIG. 7 are reconstructions of a scene obtained with impulsive illumination and the 4-by-4 array of light meters shown in FIG. 1.  FIG. 8 are reconstructions obtained with lowpass illumination and the 4-by-4 array of light meters shown in FIG. 1.
Ahmed Kirmani
Research Laboratory of Electronics, MIT
Vivek Goyal
Research Laboratory of Electronics, MIT
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

System and method for diffuse imaging with time-varying illumination intensity

US Patent Pending US 2013-0044213
Diffuse Imaging: Creating Optical Images With Unfocused Time-Resolved Illumination and Sensing
Signal Processing Letters, IEEE (Volume:19 , Issue: 1 ) , 31 October 2011. Pages 31 - 34


This technology is useful for imaging applications in which it is desirable to achieve finer resolution than provided directly by the optical components

Problem Addressed

Conventional imaging uses steady-state illumination and light sensing with focusing optics and does not exploit variations of the light with time. This invention presents a new method for imaging without focusing optics such as lenses and mirrors.


This invention introduces a diffuse imaging framework through which a focused image is produced without optical focus; instead, the image is reconstructed from time-resolved measurements of light intensity in response to time-varying scene illumination. The imaging system is made up of a source of scene illumination with intensity varying in time, a light meter for time-resolved measurement of the intensity of light incident, and a means to record time-resolved light meter outputs.


  • Diffuse imaging opens up possibilities for forming images without lenses and mirrors and enables the implementation of challenging new applications such as imaging occluded scenes.
  • This technology makes building practical imaging systems using non-ultrafast, optoelectronic hardware possible.