Browse Definitions:
Definition

photometric stereo

Photometric stereo is a computer vision method of analyzing and detailing the contour and reflectivity of a surface in 3D (three-dimensional) space.  The method involves shining an external light source on that surface, moving the light and gathering multiple images based on the resulting illumination scenarios.

Photometric stereo has diverse applications, most notably facial recognition, industrial product quality assurance / quality control, and analyzing the surfaces of celestial objects, notably the moon. Unlike a 3D scan or hologram, a photometric stereo image allows the observer to remain fixed; only the location of the light source changes. Photometric stereo determines the orientations of vectors (rays in space) that run normal (perpendicular) to a surface at multiple points. As the number of points and normal vectors increases, the quality of the resulting stereo map improves.

The mathematics of photometric stereo include advanced calculus, vector analysis, and differential equations, but the basic concept is easy to imagine. If you photograph an intricate statue from a single vantage point at a certain time of day (say, noon) in direct sunlight, then anyone who looks at the photo will get a fair idea of the statue's contour. However, if you photograph that same statue from that same vantage point at hourly intervals throughout a long, sunny summer day, anyone who sees the collection of photos will get a better idea of the statue's contour because the sun will have illuminated it from several different angles. In photometric stereo, a specialized computer program would combine images resulting from hundreds, thousands or millions of light-source orientations, coming from all possible directions in 3D space, to produce a precision mathematical image of the statue's surface -- but only as seen from a single reference frame.

The concept of photometric stereo is not new; Robert J. Woodham of the University of British Columbia introduced the idea in 1980. Since that time, the advancement of computer technology has vastly improved the precision and expanded the applicability of photometric stereo processes.

 

Continue reading about photometric stereo:

Photometric Stereo: Introduction

A Photometric Stereo Approach to Face Recognition

Photometric Stereo with General, Unknown Lighting

This was last updated in February 2012

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

SearchSecurity

  • black hat

    Black hat refers to a hacker who breaks into a computer system or network with malicious intent.

  • copyright

    Copyright is a legal term describing ownership of control of the rights to the use and distribution of certain works of creative ...

  • keylogger (keystroke logger or system monitor)

    A keylogger, sometimes called a keystroke logger or system monitor, is a type of surveillance technology used to monitor and ...

SearchHealthIT

  • population health management (PHM)

    Population health management (PHM) is a discipline within the healthcare industry that studies and facilitates care delivery ...

  • ICD-10-PCS

    The International Classification of Diseases, 10th Revision, Procedure Coding System (ICD-10-PCS) is a U.S. cataloging system for...

  • U.S. National Library of Medicine (NLM)

    The U.S. National Library of Medicine (NLM) is the largest biomedical library in the world.

SearchDisasterRecovery

  • business continuity plan (BCP)

    A business continuity plan (BCP) is a document that consists of the critical information an organization needs to continue ...

  • call tree

    A call tree -- sometimes referred to as a phone tree -- is a telecommunications chain for notifying specific individuals of an ...

  • mass notification system (MNS)

    A mass notification system is a platform that sends one-way messages to inform employees and the public of an emergency.

SearchStorage

  • hybrid hard drive (HHD)

    A hybrid hard drive (HHD), sometimes known as a solid-state hybrid drive (SSHD), is a mass storage device that combines a ...

  • USB flash drive

    A USB flash drive -- also known as a stick, thumb or pen drive -- is a plug-and-play portable storage device that uses flash ...

  • open source storage

    Open source storage is data storage software developed in a public, collaborative manner that permits the free use, distribution ...

SearchSolidStateStorage

  • RRAM or ReRAM (resistive RAM)

    RRAM or ReRAM (resistive random access memory) is a form of nonvolatile storage that operates by changing the resistance of a ...

  • JEDEC

    JEDEC is a global industry group that develops open standards for microelectronics.

  • M.2 SSD

    An M.2 SSD is a solid-state drive (SSD) that conforms to a computer industry specification written for internally mounted storage...

SearchCloudStorage

  • RESTful API

    A RESTful application program interface breaks down a transaction to create a series of small modules, each of which addresses an...

  • cloud storage infrastructure

    Cloud storage infrastructure is the hardware and software framework that supports the computing requirements of a private or ...

  • Zadara VPSA and ZIOS

    Zadara Storage provides block, file or object storage with varying levels of compute and capacity through its ZIOS and VPSA ...

Close