US 2014/0368728 A1Published application

Methods and Apparatus for High Speed Camera

AssigneeMassachusetts Institute of Technology

InventorsRamesh Raskar, Christopher Barsi

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Abstract

In exemplary implementations of this invention, a light source illuminates a scene and a light sensor captures data about light that scatters from the scene. The light source emits multiple modulation frequencies, either in a temporal sequence or as a superposition of modulation frequencies. Reference signals that differ in phase are applied to respective subregions of each respective pixel. The number of subregions per pixel, and the number of reference signals per pixel, is preferably greater than four. One or more processors calculate a full cross-correlation function for each respective pixel, by fitting light intensity measurements to a curve, the light intensity measurements being taken, respectively, by respective subregions of the respective pixel. The light sensor comprises M subregions. A lenslet is placed over each subregion, so that each subregion images the entire scene. At least one temporal sequence of frames is taken, one frame per subregion.

Claims20

Dependent claims

A method comprising:

(a) during a time period, using a light source to illuminate a scene;
(b) during the time period, using a light sensor to capture data about light that scatters from the scene;
(c) during the time period, for each respective pixel in a set of pixels in the light sensor, applying a set of electrical reference signals to subregions of the respective pixel, such that (i) each respective reference signal in the set of electrical reference signals is applied to a respective subregion of the respective pixel to modify gain of the respective subregion, and (ii) the respective reference signals in the set of reference of electrical reference signals differ from each other in phase;
and
(d) using one or more processors to calculate a full cross-correlation function for each respective pixel out of the set of pixels, by fitting light intensity measurements to a curve, the light intensity measurements being taken, respectively, by respective subregions of the respective pixel;
in which method
(i) the light source emits a superposition of multiple modulation frequencies during at least a portion of the time period, or
(ii) the light source emits
(A) a first modulation frequency, but not a second modulation frequency, during a first portion of the time period, and
(B) the second modulation frequency, but not the first modulation frequency, during a second portion of the time period.

7 more elements

A method comprising:

(a) using a light sensor to capture, during one or more M-block-sequences, data regarding light that scatters from a scene;
(b) during the one or more M-block-sequences;
for each respective pixel in a set of pixels in the light sensor, applying a set of electrical reference signals to subregions of the respective pixel, such that (i) each respective reference signal in the set of electrical reference signals is applied to a respective subregion of the respective pixel to modify gain of the respective subregion, (ii) the respective reference signals in the set of electrical reference signals differ from each other in phase, and (iii) the number of reference signals in the set of electrical reference signals is greater than four;
and
(c) using one or more processors to calculate a full cross-correlation function for each respective pixel out of the set of pixels, by fitting light intensity measurements to a curve, the light intensity measurements being taken, respectively, by respective subregions of the respective pixel;
in which method
(i) a light source emits a superposition of multiple modulation frequencies during at least a portion of the one or more M-block-sequences, or
(ii) the light source emits
(A) a first modulation frequency, but not a second modulation frequency, during a first portion of the one or more M-block-sequences, and
(B) the second modulation frequency, but not the first modulation frequency, during a second portion of the one or more M-block-sequences.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/304,566Filed 13 Jun 2014
Priority: 18 Jun 2013
Published: 18 Dec 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H04N 23/76
Circuitry for compensating brightness variation in the scene: by influencing the image signals
H01J 31/50
Having a screen on or from which an image or pattern is formed, picked up, converted, or stored: image-conversion or image-amplification tubes,…
H04N 23/74
Circuitry for compensating brightness variation in the scene: by influencing the scene brightness using illuminating means
G01J 11/00
Measuring the characteristics of individual optical pulses or of optical pulse trains