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公开(公告)号：US10802583B2
公开(公告)日：2020-10-13
申请号：US16278100
申请日：2019-02-17
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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公开(公告)号：US10752158B2
公开(公告)日：2020-08-25
申请号：US16269566
申请日：2019-02-07
Applicant: Massachusetts Institute of Technology
Inventor： Guy Satat , Matthew Tancik , Ramesh Raskar
Abstract: A pulsed laser may illuminate a scene that is obscured by dense, dynamic and heterogeneous fog. Light may reflect back to a time-resolved camera. Each pixel of the camera may detect a single photon during each frame. The imaging system may accurately determine reflectance and depth of the fog-obscured target, without any calibration or prior knowledge of the scene depth. 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 probabilistic algorithm may take into account times of arrival of all types of measured photons, including scattered and un-scattered photons.
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33.发明申请公开(公告)号：US20190331932A1
公开(公告)日：2019-10-31
申请号：US16506762
申请日：2019-07-09
Applicant: Massachusetts Institute of Technology
IPC: G02B27/58 , G02B27/10 , G01N21/3586 , G01N21/47 , G01B9/02
Abstract: A sample may be illuminated in such a way that light passes through the sample, reflects from a set of reflectors, passes through the sample again and travels to a light sensor. The reflectors may be staggered in depth beneath the sample, each reflector being at a different depth. Light reflecting from each reflector, respectively, may arrive at the light sensor during a different time interval than that in which light reflecting from other reflectors arrives—or may have a different phase than that of light reflecting from the other reflectors. The light sensor may separately measure light reflecting from each reflector, respectively. The reflectors may be extremely small, and the separate reflections from the different reflectors may be combined in a super-resolved image. The super-resolved image may have a spatial resolution that is better than that indicated by the diffraction limit.
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公开(公告)号：US20190241114A1
公开(公告)日：2019-08-08
申请号：US16269566
申请日：2019-02-07
Applicant: Massachusetts Institute of Technology
Inventor： Guy Satat , Matthew Tancik , Ramesh Raskar
Abstract: A pulsed laser may illuminate a scene that is obscured by dense, dynamic and heterogeneous fog. Light may reflect back to a time-resolved camera. Each pixel of the camera may detect a single photon during each frame. The imaging system may accurately determine reflectance and depth of the fog-obscured target, without any calibration or prior knowledge of the scene depth. 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 probabilistic algorithm may take into account times of arrival of all types of measured photons, including scattered and un-scattered photons.
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公开(公告)号：US20180168440A1
公开(公告)日：2018-06-21
申请号：US15849559
申请日：2017-12-20
Applicant: Massachusetts Institute of Technology
Inventor： Anshuman Das , Ramesh Raskar
CPC classification number: A61B1/227 , A61B1/0669 , A61B5/0066 , A61B5/0082 , A61B5/6817 , A61B2562/0233 , G06K9/4661 , G06K2209/401 , G06T7/50 , G06T15/50
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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Patent Agency Ranking
公开(公告)号：US20170331990A1
公开(公告)日：2017-11-16
申请号：US15151417
申请日：2016-05-10
Applicant: Massachusetts Institute of Technology
Inventor： Barmak Heshmat Dehkordi , Ik Hyun Lee , Hisham Bedri , Ramesh Raskar
CPC classification number: H04N5/2256 , 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：US20170234985A1
公开(公告)日：2017-08-17
申请号：US15431713
申请日：2017-02-13
Applicant: Massachusetts Institute of Technology
Inventor： Achuta Kadambi , James Schiel , Ayush Bhandari , Ramesh Raskar , Vage Taamazyan
CPC classification number: G01S17/89 , G01S7/4915 , G01S17/10 , G01S17/32 , G01S17/325
Abstract: In some implementations, scene depth is extracted from dual frequency of a cross-correlation signal. A camera may illuminate a scene with amplitude-modulated light, sweeping the modulation frequency. For each modulation frequency in the sweep, each camera pixel may measure a cross-correlation of incident light and of a reference electrical signal. Each pixel may output a vector of cross-correlation measurements acquired by the pixel during a sweep. A computer may perform an FFT on this vector, identify a dual frequency at the second largest peak in the resulting power spectrum, and calculate scene depth as equal to a fraction, where the numerator is the speed of light times this dual frequency and the denominator is four times pi. In some cases, the two signals being cross-correlated have the same phase as each other during each cross-correlation measurement.
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公开(公告)号：US09662014B2
公开(公告)日：2017-05-30
申请号：US15099270
申请日：2016-04-14
Applicant: Massachusetts Institute of Technology
Inventor： Tristan Swedish , Karin Roesch , Ramesh Raskar
CPC classification number: A61B3/152 , A61B3/0025 , A61B3/0033 , A61B3/0041 , A61B3/0091 , A61B3/12
Abstract: A retinal imaging device includes a camera, a light source, a projector, an I/O device and a computer. The projector emits two sets of light rays, such that one set of rays lies on an exterior surface of a first cone, and the other set of rays lie on an exterior surface of a second cone. The user adjusts the position of his or her eye relative to the camera, until the rays form a full, undistorted target image on the retina. This full, undistorted image is only seen when the pupil of the eye is positioned in the intersection of the first and second cones, and the eye is thus aligned with the camera. The user provides input, via the I/O device, that the user is seeing this image. The computer then instructs the camera to capture retinal images and the light source to simultaneously illuminate the retina.
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公开(公告)号：US20160302665A1
公开(公告)日：2016-10-20
申请号：US15099270
申请日：2016-04-14
Applicant: Massachusetts Institute of Technology
Inventor： Tristan Swedish , Karin Roesch , Ramesh Raskar
CPC classification number: A61B3/152 , A61B3/0025 , A61B3/0033 , A61B3/0041 , A61B3/0091 , A61B3/12
Abstract: A retinal imaging device includes a camera, a light source, a projector, an I/O device and a computer. The projector emits two sets of light rays, such that one set of rays lies on an exterior surface of a first cone, and the other set of rays lie on an exterior surface of a second cone. The user adjusts the position of his or her eye relative to the camera, until the rays form a full, undistorted target image on the retina. This full, undistorted image is only seen when the pupil of the eye is positioned in the intersection of the first and second cones, and the eye is thus aligned with the camera. The user provides input, via the I/O device, that the user is seeing this image. The computer then instructs the camera to capture retinal images and the light source to simultaneously illuminate the retina.
Abstract translation: 视网膜成像装置包括相机，光源，投影仪，I / O装置和计算机。 投影仪发射两组光线，使得一组光线位于第一锥体的外表面上，另一组光线位于第二锥体的外表面上。 使用者调整他或她的眼睛相对于照相机的位置，直到光线在视网膜上形成一个完整的，未失真的目标图像。 仅当眼睛的瞳孔位于第一和第二锥体的交叉点中时，才能看到这个完整的未失真的图像，因此眼睛与相机对准。 用户通过I / O设备提供用户看到此图像的输入。 然后，计算机指示相机捕获视网膜图像和光源以同时照亮视网膜。
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公开(公告)号：US11181623B2
公开(公告)日：2021-11-23
申请号：US16147870
申请日：2018-09-30
Applicant: Massachusetts Institute of Technology
Inventor： Achuta Kadambi , Tomohiro Maeda , Ayush Bhandari , Barmak Heshmat Dehkordi , Ramesh Raskar
IPC: G01S7/00 , G01S7/4912 , G02F1/03 , G01S7/481 , G02F1/21 , G01S17/36 , G01S17/894
Abstract: A time-of-flight imaging system may output light with a modulation frequency in the gigahertz band, to illuminate a range target. This high-frequency illumination may enable extremely precise—e.g., micron-scale—depth measurements. The system may modulate reflected light from the range target, to create a beat tone that has a frequency in the hertz band. In some cases, the modulated light in the gigahertz band is created by a first modulator and the beat tone in the hertz band is created by a second modulator. In some cases, the modulated light in the gigahertz band is created by an upshift cascade of modulators and the beat tone in the hertz band is created by a downshift cascade of modulators. A photodetector may measure the low-frequency beat tone. From this beat tone, phase of the signal and depth of the range target may be extracted.
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