NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Real-Time Feature Tracking Using HomographyThis software finds feature point correspondences in sequences of images. It is designed for feature matching in aerial imagery. Feature matching is a fundamental step in a number of important image processing operations: calibrating the cameras in a camera array, stabilizing images in aerial movies, geo-registration of images, and generating high-fidelity surface maps from aerial movies. The method uses a Shi-Tomasi corner detector and normalized cross-correlation. This process is likely to result in the production of some mismatches. The feature set is cleaned up using the assumption that there is a large planar patch visible in both images. At high altitude, this assumption is often reasonable. A mathematical transformation, called an homography, is developed that allows us to predict the position in image 2 of any point on the plane in image 1. Any feature pair that is inconsistent with the homography is thrown out. The output of the process is a set of feature pairs, and the homography. The algorithms in this innovation are well known, but the new implementation improves the process in several ways. It runs in real-time at 2 Hz on 64-megapixel imagery. The new Shi-Tomasi corner detector tries to produce the requested number of features by automatically adjusting the minimum distance between found features. The homography-finding code now uses an implementation of the RANSAC algorithm that adjusts the number of iterations automatically to achieve a pre-set probability of missing a set of inliers. The new interface allows the caller to pass in a set of predetermined points in one of the images. This allows the ability to track the same set of points through multiple frames.
Document ID
20100033562
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other - NASA Tech Brief
External Source(s)
http://www.techbriefs.com/component/content/article/8444
Authors
Clouse, Daniel S. (California Inst. of Tech. Pasadena, CA, United States)
Cheng, Yang (California Inst. of Tech. Pasadena, CA, United States)
Ansar, Adnan I. (California Inst. of Tech. Pasadena, CA, United States)
Trotz, David C. (California Inst. of Tech. Pasadena, CA, United States)
Padgett, Curtis W. (California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 25, 2013
Publication Date
September 1, 2010
Publication Information
Publication: NASA Tech Briefs, September 2010
Subject Category
Man/System Technology And Life Support
Report/Patent Number
NPO-46916
Distribution Limits
Public
Copyright
Public Use Permitted.

Related Records

IDRelationTitle20100033535Collected WorksNASA Tech Briefs, September 2010
No Preview Available