A self-calibrating, camera-based eye tracker for the recording of rodent eye movements (Zoccolan et al, 2010)

Came across an interesting methods article in "Frontiers in Neuroscience" published in late November last  year which involves the development of a fully automated eye tracking system which is calibrated without requiring co-operation from the subject. This is done by fixing the location of the eye and moving the camera to establish a geometric model (also see Stahl et al, 2000, 2004). Apparently they attempted to use a commercial EyeLink II device first but found it not suitable for rodent eye tracking due to thresholding implementation, illumination conditions and failing corneal reflection tracking when the rodent was chewing. So the authors built their own solution using a Prosilica camera and a set of algorithms (depicted below). Read the paper for implementation details. I find it to be a wonderful piece of work, different  from human eye tracking for sure but still relevant and fascinating.

Schematic diagram of the eye-tracking system

 Illustration of the algorithm to track the eye’s pupil and corneal

reflection spot.

Eye coordinate system and measurements

Horizontal and vertical alignment of the eye with the center of

the camera’s sensor.

Abstract:

"Much of neurophysiology and vision science relies on careful measurement of a human or animal subject’s gaze direction. Video-based eye trackers have emerged as an especially popular option for gaze tracking, because they are easy to use and are completely non-invasive. However, video eye trackers typically require a calibration procedure in which the subject must look at a series of points at known gaze angles. While it is possible to rely on innate orienting behaviors for calibration in some non-human species, other species, such as rodents, do not reliably saccade to visual targets, making this form of calibration impossible. To overcome this problem, we developed a fully automated infrared video eye-tracking system that is able to quickly and accurately calibrate itself without requiring co-operation from the subject. This technique relies on the optical geometry of the cornea and uses computer-controlled motorized stages to rapidly estimate the geometry of the eye relative to the camera. The accuracy and precision of our system was carefully measured using an artificial eye, and its capability to monitor the gaze of rodents was verified by tracking spontaneous saccades and evoked oculomotor reflexes in head-fixed rats (in both cases, we obtained measurements that are consistent with those found in the literature). Overall, given its fully automated nature and its intrinsic robustness against operator errors, we believe that our eye-tracking system enhances the utility of existing approaches to gaze-tracking in rodents and represents a valid tool for rodent vision studies."

• Zoccolan DF, Graham BJ, Cox DD (2010) A self-calibrating, camera-based eye tracker for the recording of rodent eye movements. Frontiers in Neuroscience Methods. doi:10.3389/fnins.2010.00193 [link]

EyeTech Digital Systems

Arizona-based EyeTech Digital Systems offers several interesting eye trackers where the new V1 caught my attention with its extended track-box of 25 x 18 x 50cm. The rather large depth range is provided through a custom auto focus mechanism developed in cooperation with Brigham Young University Dept. of Mechanical Engineering. This makes the device particularly suitable for larger displays such as public displays/digital signage, still the I'd imaging the calibration procedure to remain, ideally you'd want to walk up and interact/collect data automatically without any wizards or intervention. In any case, a larger trackbox is always welcome and it certainly opens up new opportunities. EyeTechs V1 offers 20cm more than most.

Spring eye tracker in action

More videos of the Spring eye tracker is available at the company website.

Taiwanese Utechzone, the Spring gaze interaction system

UTechZone a Taiwanese company have launched the Spring gaze interaction system for individuals with ALS or similar conditions. It provides the basic functionality including text entry, email, web, media etc. in a format that reminds much of the MyTobii software. The tracker can be mounted in various ways including wheelchairs and desks with the accessories. A nice feature is the built in TV tuner which is accessible through the gaze interface. The performance of the actual tracking system and accuracy in gaze estimation is unknown, only specified to a 7x4 grid. Track-box is specified to 17cm x 10cm x 15cm with a working range of 55-70 cm.

The system runs on Windows XP and a computer equipped with an Intel Dual Core CPU, 2GB RAM, a 500GB HD combined with a 17" monitor.
Supported languages are Traditional Chinese, Simplified Chinese, English and Japanese. All countries with pretty big markets. Price unknown but probably less than a Tobii. Get the product brochure (pdf). 

Call for papers: UBICOMM 2011

"The goal of the International Conference on Mobile Ubiquitous Computing, Systems, Services and Technologies, UBICOMM 2011, is to bring together researchers from the academia and practitioners from the industry in order to address fundamentals of ubiquitous systems and the new applications related to them. The conference will provide a forum where researchers shall be able to present recent research results and new research problems and directions related to them. The conference seeks contributions presenting novel research in all aspects of ubiquitous techniques and technologies applied to advanced mobile applications."   All tracks/topics are open to both research and industry contributions. More info.
Tracks:

• Fundamentals
• Mobility
• Information Ubiquity
• Ubiquitous Multimedia Systems and Processing
• Wireless Technologies
• Web Services
• Ubiquitous networks
• Ubiquitous devices and operative systems
• Ubiquitous mobile services and protocols
• Ubiquitous software and security
• Collaborative ubiquitous systems
• User and applications

Deadlines:

• Submission (full paper) June 20, 2011
• Notification July 31, 2011
• Registration August 15, 2011
• Camera ready August 20, 2011

Face tracking for 3D displays without glasses.

A number of manufacturers and research institutes have presented 3D display systems that utilizes real time face and eye region tracking in order to adjust the stereoscopic display in real time. This means that viewers doesn't have to wear any funky glasses to see the 3D content which has been a limiting factor for these displays. Some prototypes and OEM solutions were introduced at CEBIT last year. At CES2011 Toshiba presented a 3D equipped laptop that uses the built-in webcam to track the position of the users face (appears to be built around Seeingmachines faceAPI). It's an interesting development, we're seeing more and more of computer vision applications in the consumer space, recently Microsoft announced that they've sold 8 million Kinect devices in the first 60 days while Sony shipped 4.1 million Playstation Move in the first two months.

3D displays sans glasses at CEBIT2010

Toshibas 3D laptop sans glasses at CES2011.

Obviously, these systems differ from eye tracking systems but still share many concepts. So whats the limiting factor for consumer eye tracking then? 1) Lack of applications, there isn't a clear compelling reason for most consumers to get an eye tracker. It has to provide a new experience with a clear advantage and value. Doing something faster, easier or in a way that couldn't be done before. 2) Expensive hardware, they are professional devices manufactured in low volume with the use of high quality, expensive components 3) No guarantees, doesn't work for all customers in all environments. How do you sell something that only works under specific conditions for say 90% of the customers?

Eye HDR: gaze-adaptive system for displaying high-dynamic-range images (Rahardja et al)

"How can high dynamic range (HDR) images like those captured by human vision be most effectively reproduced? Susanto Rahardja, head of the Signal Processing Department at the A*STAR Institute for Infocomm Research (I²R), hit upon the idea of simulating the human brain’s mechanism for HDR vision. “We thought about developing a dynamic display system that could naturally and interactively adapt as the user’s eyes move around a scene, just as the human visual system changes as our eyes move around a real scene,” he says.

Two years ago, Rahardja initiated a program on HDR display bringing together researchers with a vriety of backgrounds. “We held a lot of brainstorming sessions to discuss how the human visual system perceives various scenes with different levels of brightness,” says Farzam Farbiz, a senior research fellow of the Signal Processing Department. They also read many books on cerebral physiology to understand how receptors in the retina respond to light and convert the data into electric signals, which are then transmitted to retinal ganglion cells and other neural cells through complex pathways in the visual cortex.

The EyeHDR system employs a commercial eye-tracker device that follows the viewer’s eyes and records the eyes’ reflection patterns. Using this data, the system calculates and determines the exact point of the viewer’s gaze on the screen using special ‘neural network’ algorithms the team has developed.

“On top of that, we also had to simulate the transitional latency of human eyes,” says Corey Manders, a senior research fellow of the Signal Processing Department. “When you move your gaze from a dark part of the room to a bright window, our eyes take a few moments to adjust before we can see clearly what’s outside,” adds Zhiyong Huang, head of the Computer Graphics and Interface Department. “This is our real natural experience, and our work is to reproduce this on-screen.”

The EyeHDR system calculates the average luminance of the region where the observer is gazing, and adjusts the intensity and contrast to optimal levels with a certain delay, giving the viewer the impression of a real scene. The system also automatically tone-maps the HDR images to low dynamic range (LDR) images in regions outside of the viewers gaze. Ultimately, the EyeHDR system generates multiple images in response to the viewer’s gaze, which contrasts with previous attempts to achieve HDR through the generation of a single, perfect HDR display image.

Eye HDR from Christian Bloch on Vimeo.

The researchers say development of the fundamental technologies for the system is close to complete, and the EyeHDR system’s ability to display HDR images on large LDR screens has been confirmed. But before the system can become commercially available, the eye-tracking devices will need to be made more accurate, robust and easier to use. As the first step toward commercialization, the team demonstrated the EyeHDR system at SIGGRAPH Asia 2009, an annual international conference and exhibition on digital content, held in Yokohama, Japan in December last year.

Although the team’s work is currently focused on static images, they have plans for video. “We would like to apply our technologies for computer gaming and other moving images in the future. We are also looking to reduce the realism gap between real and virtual scenes in emergency response simulation, architecture and science,” Farbiz says". (source)

• Susanto Rahardja, Farzam Farbiz, Corey Manders, Huang Zhiyong, Jamie Ng Suat Ling, Ishtiaq Rasool Khan, Ong Ee Ping, and Song Peng. 2009. Eye HDR: gaze-adaptive system for displaying high-dynamic-range images. In ACM SIGGRAPH ASIA 2009 Art Gallery & Emerging Technologies: Adaptation (SIGGRAPH ASIA '09). ACM, New York, NY, USA, 68-68. DOI=10.1145/1665137.1665187. (pdf, it's a one page poster)

Call for papers: ACIVS 2011

Acivs 2011 is a conference focusing on techniques for building adaptive, intelligent, safe and secure imaging systems. Acivs 2011 consists of four days of lecture sessions, both regular (25 mns) and invited presentations, poster sessions. The conference will take place in the Het Pand, Ghent, Belgium on Aug. 22-25 2011.

Topics

• Vision systems, including multi-camera systems
• Image and Video Processing (linear/non-linear filtering and enhancement, restoration, segmentation, wavelets and multiresolution, Markovian techniques, color processing, modeling, analysis, interpolation and spatial transforms, motion, fractals and multifractals, structure from motion, information geometry)
• Pattern Analysis (shape analysis, data and image fusion, pattern matching, neural nets, learning, grammatical techniques) and Content-Based Image Retrieval
• Remote Sensing (techniques for filtering, enhancing, compressing, displaying and analyzing optical, infrared, radar, multi- and hyperspectral airborne and spaceborne images)
• Still Image and Video Coding and Transmission (still image/video coding, model-based coding, synthetic/natural hybrid coding, quality metrics, image and video protection, image and video databases, image search and sorting, video indexing, multimedia applications)
• System Architecture and Performance Evaluation (implementation of algorithms, GPU implementation, benchmarking, evaluation criteria, algorithmic evaluation)

Proceedings

The proceedings of Acivs 2011 will be published by Springer Verlag in the Lecture Notes in Computer Science series. LNCS is published, in parallel to the printed books, in full-text electronic form via Springer Verlag's internet platform

Deadlines

February 11, 2011		Full paper submission
April 15, 2011		Notification of acceptance
May 15, 2011		Camera-ready papers due
May 15, 2011		Registration deadline for authors of accepted papers
June 30, 2011		Early registration deadline
Aug. 22-25 2011		Acivs 2011

Santa's been spotted - Introducing the SMI Glasses

What a year it has been in the commercial eye tracking domain. In June we had the Tobii glasses which was their entry into the head-mounted market which created some buzz online. This was followed by a high-speed remote system, the Tobii TX300, which was introduced in November. Both products competed directly with the offering from SMI which countered with the RED500 remote tracker, surpassing the Tobii system by 200 samples per second. Today it's my pleasure to introduce the SMI Glasses which brings up the competition a couple of notches. Being comparable in the neat, unobtrusive form factor they provide binocular tracking with a direct view of both eyes.

Rendered image of the upcoming SMI Glasses.

The small scene camera is located in the center of glasses which gives minimal parallax. Although the hard specs has yet to be released it is rumored to have a high resolution scene camera, long battery lifetime and an advanced IR AOA marker detection system which enables automatic mapping of gaze data to real-world objects. Furthermore, they can be used not only as blackbox system – but may be integrated with SMIs current head mounted devices, including live view, open interface for co-registration etc. Estimated availability is projected to the first half of 2011.

Thanks for all the hard work, inspiration and feedback throughout 2010, it's been an amazing year. By the looks of it 2011 appears to be a really interesting year for eye tracking. I'd like to wish everyone a Merry Christmas and a Happy New Year.

Method for Automatic Mapping of Eye Tracker Data to Hypermedia Content

Came across the United States Patent Application 20100295774 which has been filed by Craig Hennessey of Mirametrix. Essentially the system creates Regions Of Interest based on the HTML code (div-tags) to do an automatic mapping between gaze X&Y and the location of elements. This is done by accessing the Microsoft Document Object Model of an Intenet Explorer browser page to establish the "content tracker", a piece of software that generates the list of areas, their sizes and location on-screen which then are tagged with keywords (e.g logo, ad etc) This software will also keep track of several browser windows, their position and interaction state. 

"A system for automatic mapping of eye-gaze data to hypermedia content utilizes high-level content-of-interest tags to identify regions of content-of-interest in hypermedia pages. User's computers are equipped with eye-gaze tracker equipment that is capable of determining the user's point-of-gaze on a displayed hypermedia page. A content tracker identifies the location of the content using the content-of-interest tags and a point-of-gaze to content-of-interest linker directly maps the user's point-of-gaze to the displayed content-of-interest. A visible-browser-identifier determines which browser window is being displayed and identifies which portions of the page are being displayed. Test data from plural users viewing test pages is collected, analyzed and reported."

To conclude the idea is to have multiple clients equipped with eye trackers that communicates with a server. The central machine coordinates studies and stores the gaze data from each session (in the cloud?). Overall a strategy that makes perfect sense if your differentiating factor is low-cost.