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公开(公告)号：US11609328B2
公开(公告)日：2023-03-21
申请号：US16411951
申请日：2019-05-14
Applicant: Massachusetts Institute of Technology
Inventor： Guy Satat , Ramesh Raskar
Abstract: A light source may illuminate a scene that is obscured by fog. Light may reflect back to a time-resolved light sensor. For instance, the light sensor may comprise avalanche photodiodes that are not single-photon sensitive. The light sensor may perform a raster scan. The imaging system may determine reflectance and depth of the fog-obscured target. The imaging system may perform a probabilistic algorithm that exploits the fact that times of arrival of photons reflected from fog have a Gamma distribution that is different than the Gaussian distribution of times of arrival of photons reflected from the target. The imaging system may adjust frame rate locally depending on local density of fog, as indicated by a local Gamma distribution determined in a prior step. The imaging system may perform one or more of spatial regularization, temporal regularization, and deblurring.
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公开(公告)号：US10796190B2
公开(公告)日：2020-10-06
申请号：US16059144
申请日：2018-08-09
Inventor： Barmak Heshmat Dehkordi , Albert Redo-Sanchez , Ramesh Raskar , Alireza Aghasi , Justin Romberg
Abstract: A sensor may measure light reflecting from a multi-layered object at different times. A digital time-domain signal may encode the measurements. Peaks in the signal may be identified. Each identified peak may correspond to a layer in the object. For each identified peak, a short time window may be selected, such that the time window includes a time at which the identified peak occurs. A discrete Fourier transform of that window of the signal may be computed. A frequency frame may be computed for each frequency in a set of frequencies in the transform. Kurtosis for each frequency frame may be computed. A set of high kurtosis frequency frames may be averaged, on a pixel-by-pixel basis, to produce a frequency image. Text characters that are printed on a layer of the object may be recognized in the frequency image, even though the layer is occluded.
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公开(公告)号：US10755172B2
公开(公告)日：2020-08-25
申请号：US15630944
申请日：2017-06-22
Applicant: Massachusetts Institute of Technology
Inventor： Otkrist Gupta , Ramesh Raskar
Abstract: A deep neural network may be trained on the data of one or more entities, also know as Alices. An outside computing entity, also known as a Bob, may assist in these computations, without receiving access to Alices' data. Data privacy may be preserved by employing a “split” neural network. The network may comprise an Alice part and a Bob part. The Alice part may comprise at least three neural layers, and the Bob part may comprise at least two neural layers. When training on data of an Alice, that Alice may input her data into the Alice part, perform forward propagation though the Alice part, and then pass output activations for the final layer of the Alice part to Bob. Bob may then forward propagate through the Bob part. Similarly, backpropagation may proceed backwards through the Bob part, and then through the Alice part of the network.
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公开(公告)号：US10651865B2
公开(公告)日：2020-05-12
申请号：US16025991
申请日：2018-07-02
Applicant: Massachusetts Institute of Technology
Inventor： Ayush Bhandari , Felix Krahmer , Ramesh Raskar
IPC: H03M1/12 , H03K3/3565 , H03M1/16 , H03M3/00
Abstract: A self-reset ADC may take a set of temporally equidistant, modulo samples of a bandlimited, analog signal, at a sampling rate that is greater than πe samples per second, where π is Archimedes' constant and is Euler's number. The bandlimited signal may have a bandwidth of 1 Hertz and a maximum frequency of 0.5 Hertz. These conditions of sampling rate, bandwidth and maximum frequency may ensure that an estimated signal may be recovered from the set of modulo samples. This estimated signal may be equal to the bandlimited signal plus a constant. The constant may be equal to an integer multiple of the modulus of the centered modulo operation employed to take the modulo samples.
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公开(公告)号：US10529059B2
公开(公告)日：2020-01-07
申请号：US14823906
申请日：2015-08-11
Inventor： Fu-Chung Huang , Gordon Wetzstein , Brian Barsky , Ramesh Raskar
Abstract: Systems and methods for compensating for at least one optical aberration in a vision system of a viewer viewing a display. Image data for an image to be displayed is received, at least one parameter related to at least one optical aberration in the vision system of a viewer is received and an aberration compensated image to be displayed is computed based on the at least one received parameter related to the vision system of a viewer and on at least one characteristic of the light field element. The aberration compensated image is displayed on the display medium, such that when a viewer whose vision system has the at least one optical aberration views the aberration compensated image displayed on the display medium through a light field element, the aberration compensated image appears to the viewer with the at least one aberration reduced or eliminated.
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Patent Agency Ranking
公开(公告)号：US20190186901A1
公开(公告)日：2019-06-20
申请号：US16278769
申请日：2019-02-19
Applicant: Massachusetts Institute of Technology
Inventor： Achuta Kadambi , Vage Taamazyan , Boxin Shi , Ramesh Raskar
CPC classification number: G01B11/24 , G06T7/507 , G06T7/514 , G06T2207/10028 , G06T2207/10141
Abstract: A 3D imaging system uses a depth sensor to produce a coarse depth map, and then uses the coarse depth map as a constraint in order to correct ambiguous surface normals computed from polarization cues. The imaging system outputs an enhanced depth map that has a greater depth resolution than the coarse depth map. The enhanced depth map is also much more accurate than could be obtained from the depth sensor alone. In many cases, the imaging system extracts the polarization cues from three polarized images. Thus, in many implementations, the system takes only three extra images—in addition to data used to generate the coarse depth map—in order to dramatically enhance the coarse depth map.
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公开(公告)号：US10248194B2
公开(公告)日：2019-04-02
申请号：US15142165
申请日：2016-04-29
Applicant: Massachusetts Institute of Technology
Inventor： Tristan Swedish , Karin Roesch , Ramesh Raskar
Abstract: A video camera captures images of retroreflection from the retina of an eye. These images are captured while the eye rotates. Thus, different images are captured in different rotational positions of the eye. A computer calculates, for each image, the eye's direction of gaze. In turn, the direction of gaze is used to calculate the precise location of a small region of the retina at which the retroflection occurs. A computer calculates a digital image of a portion of the retina by summing data from multiple retroreflection images. The digital image of the retina may be used for many practical applications, including medical diagnosis and biometric identification. In some scenarios, the video camera captures detailed images of the retina of a subject, while the subject is so far away that the rest of the subject's face is below the diffraction limit of the camera.
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8.发明申请公开(公告)号：US20180259454A1
公开(公告)日：2018-09-13
申请号：US15487435
申请日：2017-04-14
Applicant: Massachusetts Institute of Technology
Inventor： Ayush Bhandari , Christopher Barsi , Achuta Kadambi , Ramesh Raskar
IPC: G01N21/64
CPC classification number: G01N21/6408 , G01N21/6456 , G01N2201/0691 , G01N2201/126 , G01N2201/129 , G07D7/1205 , G07D7/2016 , G07D7/205
Abstract: A light source may illuminate a scene with amplitude-modulated light. The scene may include fluorescent material. The amplitude modulation may be periodic, and the frequency of the amplitude modulation may be swept. During the sweep, a time-of-flight sensor may take measurements of light returning from the scene. A computer may calculate, for each pixel in the sensor, a vector of complex numbers. Each complex number in the vector may encode phase and amplitude of light incident at the pixel and may correspond to measurements taken at a given frequency in the sweep. A computer may, based on phase of the complex numbers for a pixel, calculate fluorescence lifetime and scene depth of a scene point that corresponds to the pixel.
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公开(公告)号：US10003725B2
公开(公告)日：2018-06-19
申请号：US15861645
申请日：2018-01-03
Applicant: Massachusetts Institute of Technology
Inventor： Barmak Heshmat Dehkordi , Ik Hyun Lee , Hisham Bedri , Ramesh Raskar
CPC classification number: H04N5/2256 , G02B6/04 , G02B6/06 , H04N5/2257
Abstract: An open-ended, incoherent bundle of optical fibers transmits light from a nearby scene. A camera captures images of the back end of the fiber bundle. Because the fiber bundle is incoherent, the captured image is shuffled, in the sense that the relative position of pixels in the image differs from the relative position of the scene regions that correspond to the pixels. Calibration is performed in order to map from the front end positions to the back-end positions of the fibers. In the calibration, pulses of light are delivered, in such a way that the time at which light reflecting from a given pulse enters a given fiber directly correlates to the position of the front end of the given fiber. A time-of-flight sensor takes measurements indicative of these time signatures. Based on the map obtained from calibration, a computer de-shuffles the image.
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公开(公告)号：US10918272B2
公开(公告)日：2021-02-16
申请号：US16732220
申请日：2019-12-31
Applicant: Massachusetts Institute of Technology
Inventor： Anshuman Das , Ramesh Raskar
Abstract: An otoscope may project a temporal sequence of phase-shifted fringe patterns onto an eardrum, while a camera in the otoscope captures images. A computer may calculate a global component of these images. Based on this global component, the computer may output an image of the middle ear and eardrum. This image may show middle ear structures, such as the stapes and incus. Thus, the otoscope may “see through” the eardrum to visualize the middle ear. The otoscope may project another temporal sequence of phase-shifted fringe patterns onto the eardrum, while the camera captures additional images. The computer may subtract a fraction of the global component from each of these additional images. Based on the resulting direct-component images, the computer may calculate a 3D map of the eardrum.
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