Andreas U Velten

US Patent:

20130100250, Apr 25, 2013

Filed:

Oct 7, 2012

Appl. No.:

13/646703

Inventors:

Ramesh Raskar - Cambridge MA, US
Andreas Velten - Madison WI, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

H04N 13/02

US Classification:

348 46

Abstract:

In exemplary implementations of this invention, a 3D range camera “looks around a corner” to image a hidden object, using light that has bounced (reflected) off of a diffuse reflector. The camera can recover the 3D structure of the hidden object.

US Patent:

20130100339, Apr 25, 2013

Filed:

Oct 7, 2012

Appl. No.:

13/646719

Inventors:

Ramesh Raskar - Cambridge MA, US
Andreas Velten - Madison WI, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G03B 17/17

US Classification:

348369

Abstract:

In exemplary implementations of this invention, a set of two scanning mirrors scans the one dimensional field of view of a streak camera across a scene. The mirrors are continuously moving while the camera takes streak images. Alternately, the mirrors may only between image captures. An illumination source or other captured event is synchronized with the camera so that for every streak image the scene looks different. The scanning assures that different parts of the scene are captured.

US Patent:

20120300062, Nov 29, 2012

Filed:

May 23, 2012

Appl. No.:

13/479185

Inventors:

Rohit Pandharkar - Pune, IN
Andreas Velten - Madison WI, US
Ramesh Raskar - Cambridge MA, US

Assignee:

MASSACHUSETTS INSTITUTE OF TECHNOLOGY - Cambridge MA

International Classification:

H04N 7/18

US Classification:

348135, 348E07085

Abstract:

In exemplary implementations of this invention, a time of flight camera (ToF camera) can estimate the location, motion and size of a hidden moving object, even though (a) the hidden object cannot be seen directly (or through mirrors) from the vantage point of the ToF camera (including the camera's illumination source and sensor), and (b) the object is in a visually cluttered environment. The hidden object is a NLOS (non-line-of-sight) object. The time of flight camera comprises a streak camera and a laser. In these exemplary implementations, the motion and absolute locations of NLOS moving objects in cluttered environments can be estimated through tertiary reflections of pulsed illumination, using relative time differences of arrival at an array of receivers. Also, the size of NLOS moving objects can be estimated by backprojecting extremas of NLOS moving object time responses.

US Patent:

20200284907, Sep 10, 2020

Filed:

Mar 8, 2019

Appl. No.:

16/297320

Inventors:

- Madison WI, US
Atul Ingle - Madison WI, US
Andreas Velten - Madison WI, US
Mohit Gupta - Madison WI, US

International Classification:

G01S 17/10
G01S 17/89
G01S 7/484
G01S 7/486
H01L 31/107

Abstract:

In accordance with some embodiments, systems, methods and media for single photon depth imaging with improved precision in ambient light conditions are provided. In some embodiments, the system comprises: a light source; a single photon detector; an attenuation element configured to provide a variable intensity attenuation factor; and a processor programmed to: (a)-determine an ambient light intensity associated with a scene point; (b)-select an attenuation factor based on the ambient light intensity; (c)-estimate a depth of the scene point based on a multiplicity of photon arrival times determined using the detector during a period of time during which light incident on the detector is attenuated by the selected attenuation factor and during which the light source is configured to periodically emit a pulse of light toward the scene point; (d)-repeat (a)-(c) for each of a multiplicity of scene points.

US Patent:

20200036918, Jan 30, 2020

Filed:

Jul 27, 2018

Appl. No.:

16/047933

Inventors:

- Madison WI, US
Mohit Gupta - Madison WI, US
Andreas Velten - Madison WI, US

International Classification:

H04N 5/355
H04N 5/369
H04N 5/374
H04N 5/3745

Abstract:

In accordance with some embodiments, systems, methods and media for high dynamic range imaging using dead-time-limited single photon detectors are provided. In some embodiments, a system for high dynamic range imaging is provided, comprising: an image sensor comprising: a pixels comprising: a single photon detector having dead time τ; and a counter coupled to an output of the single photon detector, wherein the counter is configured to increment in response to a signal indicative of detection of a photon output by the single photon detector; and a processor that is programmed to: read out a value stored by the counter after an exposure time has elapsed; and calculate an intensity for the pixel based on the value and the dead time τ.

US Patent:

20190146073, May 16, 2019

Filed:

Sep 8, 2017

Appl. No.:

15/699623

Inventors:

- Madison WI, US
- New York NY, US
Andreas Velten - Madison WI, US
Eric Breitbach - Madison WI, US
Shree K. Nayar - New York NY, US

International Classification:

G01S 7/491
G06T 7/521
H04N 5/225
G01S 17/32
G01S 17/89

Abstract:

In accordance with some embodiments, systems, methods and media for encoding and decoding signals used in time-of-flight imaging are provided. In some embodiments, a method for estimating the depth of a scene is provided, comprising: causing a light source to emit modulated light toward the scene based on a modulation function; causing the image sensor to generate a first value based on the modulated light and a first demodulation function of K modulation functions; causing the image sensor to generate a second value; causing the image sensor to generate a third value; and determining a depth estimate for the portion of the scene based on the first value, the second value, the third value, and three correlation functions each including at least one half of a trapezoid wave.

US Patent:

20180309970, Oct 25, 2018

Filed:

Apr 20, 2017

Appl. No.:

15/492969

Inventors:

- Madison WI, US
- New York NY, US
Andreas Velten - Madison WI, US
Shree K. Nayar - New York NY, US

International Classification:

H04N 13/02
G06T 7/521
H04N 13/00

Abstract:

In accordance with some embodiments, systems, methods and media for encoding and decoding signals used in time-of-flight imaging are provided. In some embodiments, a method for estimating the depth of a scene is provided, comprising: causing a light source to emit modulated light toward the scene based on a modulation function; causing the image sensor to generate a first value based on the modulated light and a first demodulation function of K modulation functions, including at least one trapezoid wave; causing the image sensor to generate a second value; causing the image sensor to generate a third value; and determining a depth estimate for the portion of the scene based on the first value, the second value, and the third value.

US Patent:

20150025391, Jan 22, 2015

Filed:

Jul 19, 2013

Appl. No.:

13/946363

Inventors:

- Madison WI, US
Adam Uselmann - Madison WI, US
Andreas Velten - Madison WI, US
Surendra Prajapati - Madison WI, US
Kevin Eliceiri - Madison WI, US

Assignee:

Wisconsin Alumni Research Foundation - Madison WI

International Classification:

A61B 5/00
G01J 1/44
G01J 1/58

US Classification:

600476

Abstract:

Fluorescent markers used to identify a tissue may be imaged in a bright environment by synchronizing the imaging process with rapidly switched ambient lighting so that imaging occurs in phase with a switching off of the ambient lighting. In this way, valuable fluorescent imaging may be performed in an environment that appears to be brightly illuminated, for example in the area of a surgical suite.