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
Dave Sossen
MIT Technology Licensing Officer
Patent Protection

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

US Patent Pending 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.