Extracting feature quantities from an image to perform location estimation

Patent metadata

Field	Value
Publication number	US-9020196-B2
Application number	US-201314022368-A
Country	US
Kind code	B2
Filing date	Sep 10, 2013
Priority date	Aug 15, 2012
Publication date	Apr 28, 2015
Grant date	Apr 28, 2015

Abstract

A feature extraction method for extracting a feature from an image includes receiving an image and measured acceleration data from a mobile device; obtaining a gravity vector in the image in a camera coordinate system based on the measured acceleration data; obtaining a vanishing point in the image in a vertical direction in a screen coordinate system using the gravity vector; obtaining differential vectors along two axes for each pixel in the screen coordinate system; obtaining a connection line vector connecting each of the pixels with the vanishing point; identifying a vertical edge based on determining that an angle formed by the differential vector and the connection line vector is within a certain threshold range; obtaining the sum of strengths of vertical edges and writing the sum in a predetermined variable array; extracting a keypoint based on the variable array; and calculating a feature quantity from the keypoint.

First claim

The invention claimed is:

1. A feature extraction system for extracting a feature from an image by computer processing, the system comprising:
means for receiving an image and measured acceleration data from a mobile device including image acquiring means and acceleration measuring means;
means for obtaining a gravity vector in the image in a camera coordinate system on the basis of the measured acceleration data;
means for obtaining a vanishing point in the image in a vertica…

Assignees

• IBM

Inventors

• Takahashi Toshihiro

Classifications

• G06V30/142 Primary

  Physics · mapped topic

• G06K9/4671 Primary

  Physics · mapped topic

• G06T7/0071

  Physics · mapped topic

• G06K9/228

  Physics · mapped topic

• G06T7/0042

  Physics · mapped topic