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Eye Tracking Techniques and applications. eie426-EyeTracking-200903.ppt. Outline. Part I :Physiology of the EYE Part II : Mechanism of Eye Movements Part III :Eye Tracking Technology Part IV :Eye Tracking Applications. How does our eye work. Part I :Physiology of the EYE.
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Eye Tracking Techniques and applications eie426-EyeTracking-200903.ppt EIE426-AICV
Outline • Part I :Physiology of the EYE • Part II : Mechanism of Eye Movements • Part III :Eye Tracking Technology • Part IV :Eye Tracking Applications EIE426-AICV
How does our eye work EIE426-AICV
Part I :Physiology of the EYE HOW DOES OUR EYE WORK EIE426-AICV
Part II : Mechanism of Eye Movements CAN YOU BELIEVE YOUR EYE EIE426-AICV
Part III :Eye Tracking Technology HOW EYE TRACKER WORKS EIE426-AICV
Outline • Current State and Application of Eye Gaze Tracking (EGT) Technology • Theory and the Classification of EGT Technology • The Framework of EGT system
Ⅰ. Current State and Application of Eye Gaze Tracking (EGT) Technology
Ⅰ. Current State and Application of Eye Gaze Tracking (EGT) Technology • What is EGT eye gaze——The line from the fovea through the center of the pupil is the line of sight (LoS). Usually, we take the optical axis as line of gaze (LoG). LoG can be approximate to LoS. In fact, LoS determines a person’s visual attention. eye gaze Tracking——By image Processing,if the LoG or LoS can be estimated, the point of regard (POR) is computed as the intersection of the LoG (or LoS) with the object of the scene or space. • History and Development of EGT Interests of Visual attention can be traced back to 1897. At that time, it was a kind of diagnostic research, i.e. the recording of eye movement. Those technologies include ophthalmometer, Mechanical Method, Electro-Oculography (EOG), Optical-based Method , electromagnetic Oculography eye movement initially applied in medical research, such as brain and physiology analysis. with the development of Electronics, Computer and Image processing technology, further research focuses on Eye Gaze Tracking Technology .
Ⅰ. Current State and Application of Eye Gaze Tracking (EGT) Technology • eye tracking techniques: • Direct Observation: ophthalmometer,peep-hole method • Mechanic Method:use level to record eye movement • Optical-based Method:Reflection Method (mirror or prism)、Pupil-Corneal reflection、Purkinje Image • Electro-Oculography (EOG): recorded the difference in the skin potential • Electromagnetic Oculography :The users gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field Except Optical-based Method, the above methods are more or less low accuracy or high intrusiveness . As a result, Modern Eye Gaze Tracking Techniques are mostly based on Optical-based Method.
Ⅱ. Theory and the Classification of EGT Technology • Image-Based EGT Technology • Infrared Light : out of visible light; Paired with filter to eliminate the light of other wavelength; • Eye camera :tracking eye movement and recording eye image sequence • Image Processing: detecting the visual elements • Further Estimation:。Having pre-processed, the data of eye gaze can be get from eye-movement model
Input Image acquisition Feature Estimation Image Processing Output Data Estimation Eye Tracking Calibration Ⅱ. Theory and the Classification of EGT Technology System Framework
Image acquisition: get bright pupil or dark pupil Image Processing :Filtering ,Noise reducing ,difference ,thresholding 1 2 3 4 5 Feature Estimation:Estimating the center of Pupil and corneal reflection Eye Tracking: Estimation of eye gaze Ⅱ. Theory and the Classification of EGT TechnologyFunction of Each Module Data Estimation: Algorithm validation ,eye movement data analysis
Theory of EGT Technology • 2D to detect the Optical Axis (basic) • 2D to detect the Line of Sight (Advanced)
view of humanity • View of appearance Classification of EGT Technology • view of application
Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Humanity Usually By goggle , helmet … features:high accuracy defects:intrusiveness Head MountedEye Tracker Usually on table features:non-intrusive defects:eye and head relative motion Remote Eye Tracker
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. By placing IR light emitting diodes and photo-transistors, respectively, above and below the eye.the resulting voltage difference is proportional to the angular deviation of the eye. Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. This boundary can easily be optically detected and tracked Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement The Limbus is the boundary between the white sclera and the dark iris of the eye. By placing IR light emitting diodes and photo-transistors, respectively, above and below the eye.the resulting voltage difference is proportional to the angular deviation of the eye. The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. 将两对氯化银皮肤表面电极分别置于眼睛左右、上下两侧, 就能引起眼球变化方向上的微弱电信号, 经放大后得到眼球运动的位置信息 Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. This boundary can easily be optically detected and tracked Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. 将两对氯化银皮肤表面电极分别置于眼睛左右、上下两侧, 就能引起眼球变化方向上的微弱电信号, 经放大后得到眼球运动的位置信息 Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. This boundary can easily be optically detected and tracked Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement The Limbus is the boundary between the white sclera and the dark iris of the eye. By placing IR light emitting diodes and photo-transistors, respectively, above and below the eye. the resulting voltage difference is proportional to the angular deviation of the eye. By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. 将两对氯化银皮肤表面电极分别置于眼睛左右、上下两侧, 就能引起眼球变化方向上的微弱电信号, 经放大后得到眼球运动的位置信息 Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. This boundary can easily be optically detected and tracked Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. 将两对氯化银皮肤表面电极分别置于眼睛左右、上下两侧, 就能引起眼球变化方向上的微弱电信号, 经放大后得到眼球运动的位置信息 Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. This boundary can easily be optically detected and tracked Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. 将两对氯化银皮肤表面电极分别置于眼睛左右、上下两侧, 就能引起眼球变化方向上的微弱电信号, 经放大后得到眼球运动的位置信息 Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
The Purkinje images are reflections created at different layers of the eye structure. Eye gaze can be calculated from these relative positions of these reflections The Limbus is the boundary between the white sclera and the dark iris of the eye. This boundary can easily be optically detected and tracked Training images are taken when the user is looking at a specific Calibration markers. Use ANN to decide the eye gaze Use a small coil embedded into a contact lens that is tightly fit over the sclera . The user’s gaze is estimated from measuring the voltage induced in the search coil by an external electro-magnetic field. The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement The IR source can generate a glint on corneal and divide pupil from iris, the difference between can represent the eye gaze movement By placing electrodes around the eye, it is possible to measure small differences in the skin potential corresponding to eye movement. 将两对氯化银皮肤表面电极分别置于眼睛左右、上下两侧, 就能引起眼球变化方向上的微弱电信号, 经放大后得到眼球运动的位置信息 Ⅱ. Theory and the Classification of EGT TechnologyFrom View of Theory Purkinje Image EOG Limbus-Scalar IR Tracking ANN Contact Lens Pupil-Corneal reflection
view of humanity • 从系统应用角度 Ⅱ. Theory and the Classification of EGT TechnologyFeature of Eye Movement
Ⅱ. Theory and the Classification of EGT TechnologyDevelopment • Early stage : Direct Observation ,Mechanical Method • Initial Methods, not used any more for high intrusiveness and poor accuracy • Development:EOG、 Electromagnetic OculographyAlthough have improved a lot and widely used , these method are disappearing because of the intrusiveness • Advanced:Optical Method:Because of its’ high accuracy and low intrusiveness, Optical Method have made rapid progress in recent years. • The Purkinje images are reflections created at different layers of the eye structure. and the eye gaze can be calculated from these relative positions of these reflections • Photo-Oculography : it measures the eye movement during it's translation/rotation. with the IR light source, shape of the pupil ,Limbus or corneal reflection is detected • Limbus-Scalar IR Method: They place IR light emitting diodes and IR light sensitive photo-transistors, respectively, above and below the eye. Several such IR pairs can be mounted on goggles or helmets, a photo-transistor transforms the reflected IR light into a voltage. the resulting voltage difference is proportional to the angular deviation of the eye. • Pupil-Corneal Reflection: The IR source can generate a glint on corneal and divide pupil from iris, the camera can extract the pupil which represent the eye gaze, on the other hand the corneal reflection represent the head motion, as a result, the difference between them represents the real eye gaze movement.。
View of appearance Ⅱ. Theory and the Classification of EGT TechnologyFeature of Remote Eye Gaze Tracker • Robustness • Light Source • Eyelash, Eyelids and Camera Position • System Error • Eye station (dry or wet) • head motion • Lower accuracy than Head Mounted Eye Tracker
Ⅲ A Practical Eye Gaze Tracking SystemFramework of EGT System • Hardware:a Pair of Cameras • eye camera • scene camera • eye camera is for acquisition of pupil corneal reflection image, scene camera is for: 1 mapping from the eye image coordinate to scene image coordinate ;2 Showing the combining result of POR and scene in same image:
Ⅲ A Practical Eye Gaze Tracking Systemappearance of EGT System
Ⅲ Practical Eye Gaze Tracking SystemTheory of a Head Mounted Eye Tracker
Ⅲ Practical Eye Gaze Tracking SystemBright Pupil and Dark Pupil Bright Pupil Dark Pupil Difference Image • When IR source is placed near the optical axis of the camera bright pupil as can be seen ;while IR is placed off the optical axis, a dark pupil can be seen. By Thresholding, a robust pupil contour can be extracted .
Dark Pupil Corneal Reflection Ⅲ Practical Eye Gaze Tracking SystemBright Pupil and Dark Pupil Bright Pupil • The IR source can generate a glint on corneal and divide pupil from iris, the camera can extract the pupil which represent the eye gaze, on the other hand the corneal reflection represent the head motion, as a result, the difference between them represents the real eye gaze movement.
Part IV :Applications HOW FAR YOU CAN FLY EIE426-AICV
Applications • Human Computer Interaction (HCI)—— efficiency, humanity • Intelligent Control —— EGT and Weapon Control • Human Movement Study ——Typing, physical training • Psychology —— Antinational Neuroscience, • Visual attention & Driving ——Aviation, navigation, driving, traffic accidents inspection • Scene and Image Perception—— Web, AD, Designing, Scene EIE426-AICV