Patents by Inventor Anand Krishna Asundi
Anand Krishna Asundi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 10180564Abstract: A transport-of-intensity imaging system is proposed which incorporates a control element positioned in an optical relay system, such as a 4f optical relay system, between a microscope system for generating an image of a specimen, and an image capturing device. The control element is located with an optical relay system, and is controllable to vary the focal plane without changing the spacing of the specimen and the image capturing device. In one form the control element is an electronically tunable lens (ETL). In another form, the control element is a spatial light modulator (SLM). The arrangement may include a beam splitter arrangement for generating a plurality of beams, which are not all subject to the same control element, such that multiple images with different focal planes are captured from the respective beams.Type: GrantFiled: July 2, 2014Date of Patent: January 15, 2019Assignee: NANYANG TECHNOLOGICAL UNIVERSITYInventors: Anand Krishna Asundi, Chao Zuo
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Publication number: 20180274979Abstract: Various embodiments provide an optical sensor having an optical source, a grating arrangement optically coupled to the optical source to receive a source optical signal from the optical source, the grating arrangement including a chirped FBG having a defined spectral profile, wherein, in response to a first change in at least one parameter interacting with the chirped FBG, the defined spectral profile is shifted in a first direction relative to a reference spectral profile, and the grating arrangement is configured, in response thereto, to generate a first output optical signal corresponding to the first change, and wherein, in response to a second change in the at least one parameter interacting with the chirped FBG, the defined spectral profile is shifted in a second direction relative to the reference spectral profile, and the grating arrangement is configured, in response thereto, to generate a second output optical signal corresponding to the second change.Type: ApplicationFiled: March 16, 2018Publication date: September 27, 2018Inventors: Yaowen Yang, Muneesh Maheshwari, Swee Chuan Tjln, Anand Krishna Asundi, Tanmay Chaturvedi
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Publication number: 20160139388Abstract: A transport-of-intensity imaging system is proposed which incorporates a control element positioned in an optical relay system, such as a 4f optical relay system, between a microscope system for generating an image of a specimen, and an image capturing device. The control element is located with an optical relay system, and is controllable to vary the focal plane without changing the spacing of the specimen and the image capturing device. In one form the control element is an electronically tunable lens (ETL). In another form, the control element is a spatial light modulator (SLM). The arrangement may include a beam splitter arrangement for generating a plurality of beams, which are not all subject to the same control element, such that multiple images with different focal planes are captured from the respective beams.Type: ApplicationFiled: July 2, 2014Publication date: May 19, 2016Inventors: Anand Krishna ASUNDI, Chao ZUO
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Patent number: 9322643Abstract: An apparatus for 3D surface measurement of a target surface, the apparatus comprising: a first projector configured to project a fringe pattern onto the target surface; a second projector configured to project a fringe pattern onto the target surface; a first camera configured to capture the fringe patterns projected by the first projector and the second projector; a second camera configured to capture the fringe patterns projected by the first projector and the second projector; and a computer configured to perform fringe pattern processing of the fringe patterns captured by the first camera and the second camera and to perform data stitching and merging to obtain a 3D surface reconstruction.Type: GrantFiled: October 17, 2012Date of Patent: April 26, 2016Assignee: NANYANG TECHNOLOGICAL UNIVERSITYInventors: Lei Huang, Chi Seng Ng, Hoe Jyh Koh, Anand Krishna Asundi
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Publication number: 20150069247Abstract: There is provided a method and system for real time inspection of a silicon wafer. The method includes using an infrared plane polariscope to obtain an image of a bonded interface of the silicon wafer, the image showing stress patterns; and assessment of the stress patterns. The stress patterns in a form of at least one butterfly pattern indicates a presence of at least one of: at least one trapped particle, trapped gases and at least one de-bonding region. No computer/algorithm processing is carried out to locate defects/de-bondings at the bonded interface. Furthermore, the stress fields being generated can be used to approximate the size of the de-bonding region/trapped particle. The system employs the infrared plane polariscope to obtain an image of a bonded interface of the silicon wafer.Type: ApplicationFiled: April 14, 2013Publication date: March 12, 2015Applicant: NANYANG TECHNOLOGIAL UNIVERSITYInventors: Anand Krishna Asundi, Chi Seng Ng
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Publication number: 20140253929Abstract: An apparatus for 3D surface measurement of a target surface, the apparatus comprising: a first projector configured to project a fringe pattern onto the target surface; a second projector configured to project a fringe pattern onto the target surface; a first camera configured to capture the fringe patterns projected by the first projector and the second projector; a second camera configured to capture the fringe patterns projected by the first projector and the second projector; and a computer configured to perform fringe pattern processing of the fringe patterns captured by the first camera and the second camera and to perform data stitching and merging to obtain a 3D surface reconstruction.Type: ApplicationFiled: October 17, 2012Publication date: September 11, 2014Inventors: Lei Huang, Chi Seng Ng, Hoe Jyh Koh, Anand Krishna Asundi
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Patent number: 8363316Abstract: An optical configuration for a digital holographic microscope and a method for digital holographic microscopy are presented. In one embodiment, digital off-axis holograms are obtained using a cube beam splitter (110) to both split and combine a diverging spherical wavefront emerging from a microscope objective (108). When a plane numerical reference wavefront is used for the reconstruction of the recorded digital hologram, the phase curvature introduced by the microscope objective (108) together with the illuminating wave to the object wave can be physically compensated.Type: GrantFiled: August 21, 2009Date of Patent: January 29, 2013Assignees: Nanyang Technological University, Ngee Ann PolytechnicInventors: Anand Krishna Asundi, Weijuan Qu, Oi Choo Chee
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Patent number: 8194124Abstract: A holographic microscope comprising a source configured to provide a diverging beam of radiation, a beam splitter configured to direct a first portion of the diverging beam towards an object and a second portion of the diverging beam towards a reflector, the beam splitter being further configured to direct an object beam from the object and a reference beam from the reflector towards a transducer, and the transducer being configured to provide a signal indicative of the interference pattern of the object beam and the reference beam incident on the transducer. A method of digital holography is also disclosed.Type: GrantFiled: October 9, 2007Date of Patent: June 5, 2012Assignee: Nanyang Technological UniversityInventors: Anand Krishna Asundi, Vijay Raj Singh
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Publication number: 20110043878Abstract: An optical configuration for a digital holographic microscope and a method for digital holographic microscopy are presented. In one embodiment, digital off-axis holograms are obtained using a cube beam splitter (110) to both split and combine a diverging spherical wavefront emerging from a microscope objective (108). When a plane numerical reference wavefront is used for the reconstruction of the recorded digital hologram, the phase curvature introduced by the microscope objective (108) together with the illuminating wave to the object wave can be physically compensated.Type: ApplicationFiled: August 21, 2009Publication date: February 24, 2011Applicants: Nanyang Technological University, Ngee Ann PolytechnicInventors: Anand Krishna Asundi, Weijuan Qu, Oi Choo
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Publication number: 20090091811Abstract: A holographic microscope comprising a source configured to provide a diverging beam of radiation, a beam splitter configured to direct a first portion of the diverging beam towards an object and a second portion of the diverging beam towards a reflector, the beam splitter being further configured to direct an object beam from the object and a reference beam from the reflector towards a transducer, and the transducer being configured to provide a signal indicative of the interference pattern of the object beam and the reference beam incident on the transducer. A method of digital holography is also disclosed.Type: ApplicationFiled: October 9, 2007Publication date: April 9, 2009Inventors: Anand Krishna Asundi, Vijay Raj Singh
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Patent number: 7477362Abstract: A moiré interferometric strain sensor for detecting strain on a specimen, a diffraction grating being on the specimen, the strain sensor including an array of a plurality of microlenses for receiving at least one reflected beam of at least one incident beam upon the specimen; and a detector array at a focal plane of the array of a plurality of microlenses.Type: GrantFiled: September 27, 2005Date of Patent: January 13, 2009Assignee: Nanyang Technological UniversityInventors: Anand Krishna Asundi, Anish Priyadarshi, Subodh Gautam Mhaisalkar