System for reconstructing surface motion in an optical elastography system
Inventors
Chase, James Geoffrey • Botterill, Tom
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-10244945-B2
Publication Date
2019-04-02
Expiration Date
Abstract
A method for an optical elastography system converts digital images of an actuated breast into a description of surface motion. The surface motion can subsequently be used to ascertain whether the breast has regions of abnormal stiffness, e.g., indicating a significant likelihood of breast cancer. The steps of the method use a model based segmentation to identify profile of the breast in each image, and for each pair of images computing skin surface motion using an optical flow algorithm. This method eliminates a preliminary step of placing fiducial markers on the subject.
Core Innovation
The invention relates to an optical elastography system for analyzing surface motion of body tissue of a subject, including a controller device, a vibration unit, a plurality of cameras, a strobe light, and a computational device. The controller device controls the vibration unit that stimulates body tissue by vibrating the body tissue, and the plurality of cameras are distributed about the tissue to capture a set of images at a plurality of time-steps of a surface of a region of stimulated tissue. A 3D surface model of the tissue region is developed from the set of images captured at the plurality of time-steps.
The system estimates surface motion of the vibrating body tissue region between time-step images and then estimates a 3D surface motion by combining the 3D surface model with the estimated tissue surface motion between time-step images. The captured images are segmented to extract breast contours, a parametric 3D surface model is fitted per time-step, and skin surface motion between consecutive frames is estimated via optical flow with lighting-variation correction. The reconstructed 3D motion is compared to expected healthy motion to identify abnormal stiffness and cancer likelihood.
The approach is described as eliminating fiducial markers while reconstructing 3D breast surface motion using synchronized multi-camera image sets and strobe illumination during vibration. Lighting variation correction is applied, and the processing includes segmentation and breast contour extraction, localized model fitting per time-step, and optical-flow computation to integrate the 3D surface model with estimated motion. An illustrative example includes a system with five cameras and 50 Hz actuation.
Claims Coverage
The partial content identifies one independent claim (clm-00001). Across this independent claim, the claims concentrate on five inventive aspects: multi-camera, multi-time-step capture under stimulation; developing a 3D surface model; estimating surface motion between time-step images; estimating 3D surface motion by combining the 3D surface model with the estimated surface motion; and analyzing the 3D surface motion to identify abnormalities.
Multi-camera image capture at plurality of time-steps
Capturing a set of images at a plurality of time-steps of a surface of a region of stimulated tissue with the plurality of cameras distributed about the tissue while the vibration unit stimulates the body tissue.
Developing a 3D surface model from the captured image sets
Developing a 3D surface model of the tissue region from the set of images captured at the plurality of time-steps.
Estimating surface motion between time-step images
Estimating the surface motion of the vibrating body tissue region between time-step images.
Estimating 3D surface motion by combining the 3D surface model with estimated surface motion
Estimating a 3D surface motion of the vibrating body tissue region by combining the 3D surface model with the estimated tissue surface motion between time-step images.
Analyzing 3D surface motion to identify motion abnormalities
Analyzing the 3D surface motion to identify abnormalities in the motion of the vibrating body tissue region.
Using structured light illumination to develop the 3D surface model
Forming the 3D surface model using a structured light illumination system.
Paired laser-and-grating structured light per camera
Providing, for each camera among the plurality, a structured light illumination system including a paired laser and grating arrangement.
Static light pattern
Configuring the structured light illumination system so that the light pattern remains static.
Time-of-flight camera for 3D surface modeling
Configuring the camera system and the 3D surface model to use a time-of-flight camera.
Segmentation and localized outline profile fitting per time-step
Refining the 3D tissue surface model by segmenting each image to find a tissue region, localizing an outline profile for each time-step, and estimating the tissue-region 3D surface at each time-step by fitting the 3D model to the corresponding localized profile.
The claim coverage is centered on a system that stimulates tissue, captures multi-camera images at multiple time-steps, constructs a 3D surface model, estimates surface motion between frames, combines the 3D surface model with the estimated surface motion to obtain 3D surface motion, and analyzes that motion to identify abnormalities; dependent features further refine 3D modeling via segmentation and localized outline profile fitting and constrain the imaging approach using structured light illumination (including paired laser and grating and a static light pattern) and/or time-of-flight cameras.
Stated Advantages
Reconstructing 3D breast surface motion without fiducial markers.
Identifying abnormalities in the motion of the vibrating body tissue region.
Enabling identification of abnormal stiffness and cancer likelihood by comparing reconstructed 3D motion to expected healthy motion.
Documented Applications
Breast cancer screening using optical elastography to reconstruct 3D breast surface motion and identify motion abnormalities related to cancer likelihood.
Interested in licensing this patent?