TWO MOONS SOFTWARE LTD RISEBETA EYE-TRACKER INSTRUCTION GUIDE V 1.01
CONTENTS 1 INTRODUCTION... 5 2 SUPPORTED CAMERAS... 5 3 SUPPORTED INFRA-RED ILLUMINATORS... 7 4 USING THE CALIBARTION UTILITY... 8 4.1 3D COORDINATE AXIS... 8 4.2 CAMERA PROPERTIES... 8 4.2.1 FX... 8 4.2.2 FY... 9 4.2.3 CX... 9 4.2.4 CY... 10 4.2.5 HORIZONTAL PIXELS... 10 4.2.6 VERTICAL PIXELS... 11 4.2.7 X ROTATION... 11 4.2.8 Y ROTATION... 11 4.2.9 Z ROTATION... 12 4.3 ILLUMINATOR PROPERTIES... 12 4.3.1 X... 12 4.3.2 Y... 12 4.3.3 Z... 13 4.4 SURFACE PROPERTIES... 13 4.4.1 WIDTH... 13 4.4.2 HEIGHT... 13 4.4.3 HORIZONTAL PIXELS... 14 4.4.4 VERTICAL PIXELS... 14 4.4.5 X... 14 4.4.6 Y... 15 4.4.7 Z... 15 4.4.8 X ROTATION... 15 4.4.9 Y ROTATION... 16 4.4.10 Z ROTATION... 16 4.5 TRACK-BOX PROPERTIES... 17 4.5.1 DISTANCE... 17 4.5.2 DEPTH... 17 4.5.3 NEAR RESOLUTION... 18
4.5.4 FAR RESOLUTION... 18 4.5.5 DEPTH RESOLUTION... 18 4.6 USER CALIBRATION PROPERTIES... 19 4.6.1 COLUMNS... 19 4.6.2 ROWS... 19 4.7 CREATING A CALIBRATION FILE... 19 5 USING RISE BETA... 23 5.1 MENU... 23 5.1.1 FILE... 23 5.1.2 CAMERA... 24 5.1.3 USER CALIBRATION... 24 5.1.4 TRACKING... 24 5.1.5 LOGGING... 24 5.1.6 SETTINGS... 25 5.1.7 ABOUT... 25 5.2 TOOLBAR... 25 5.2.1 SELECT CAMERA... 25 5.2.2 TRACK GAZE... 25 5.2.3 SMOOTH GAZE DATA... 25 5.2.4 LOG GAZE DATA... 25 5.2.5 EXPORT GAZE DATA... 25 5.2.6 LAUNCH CALIBRATION UTILITY... 25 5.3 RISE BETA SETTINGS... 26 5.3.1 CASCADE SETTINGS... 26 5.3.2 DETECTION SETTINGS... 29 5.4 CREATING A USER CALIBRATION... 35 5.4.1 DISPLAY SCREEN USER CALIBRATION... 35 5.4.2 GENERIC SURFACE USER CALIBRATION... 36
FIGURES Figure 1: DCC1545M Sensitivity to Near Infrared Wavelengths... 6 Figure 2: Illustration of Corneal Reflection (Glint) Produced by Infra-Red Illuminator... 7 Figure 3: Right Handed Coordinate Axis... 8 Figure 4:Track-Box in which Eye-Tracking Will Take Place.... 17 Figure 5: Creating a System Calibration... 20 Figure 6: Calibration Utility Configured for Desktop Eye-Tracking... 21 Figure 7: User Calibration Settings... 21 Figure 8: Creating a Calibration File with Calibration Utility... 22 Figure 9: RISE BETA Eye-Tracker... 23 Figure 10: RISE BETA Eye-Tracker Connected to Thorlabs DCC1545M Camera with a 16mm Focal Length Lens... 26 Figure 11: RISE BETA Cascade Settings... 27 Figure 12: RISE BETA Loaded with OpenCV Cascades... 28 Figure 13: Detection Settings... 29 Figure 14: User Calibration Window for Display Screen... 35 Figure 15: User Calibration Window for Display Screen with Typical Calibration Results... 36 Figure 16: User Calibration Window for Generic Surface... 37 Figure 17: User Calibration Window for Generic Surface with Typical Calibration Results... 38
1 INTRODUCTION RISE BETA Eye-Tracker is a highly configurable eye-tracking system for the research and early adopter community. RISE BETA uses mathematical modelling of the eye, tracking surface and the camera sensor to produce artificial calibrations. RISE BETA uses an open hardware architecture and can connect to off-the-shelf cameras using either the Microsoft DirectShow or Microsoft Media Foundation interfaces. Like other commercial eye-trackers, RISE BETA uses an adaptation of the pupilcenter-corneal-reflection eye-tracking algorithm which works by detecting a corneal reflection (glint) produced on the surface of the cornea by an infra-red illuminator. Because RISE BETA uses an open-hardware design, it is important to select a suitable camera, lens and infra-red illuminator. 2 SUPPORTED CAMERAS RISE BETA can connect to off-the-shelf cameras using either the Microsoft DirectShow or Microsoft Media Foundation interfaces. Because RISE BETA uses an adaptation of the pupil-center-cornealreflection algorithm, which works by detecting a corneal reflection (glint) produced on the surface of the cornea by an infra-red illuminator, the camera needs to have a high degree of sensitivity to Near- Infrared (NIR) wavelengths.
SUPPORTED CAMERAS: The examples given in this guide uses the Thorlabs DCC1545M CMOS camera. This is a relatively inexpensive machine vision camera. The example uses a SIMA 36 LED infra-red light which has LEDs in the 850nm wavelength. From Figure 1, the DCC 1545M camera has a Quantum Efficiency of approximately 20%. This is sufficient when the camera and illuminator is approximately 60cm (arm s length) from the user s eyes. Figure 1: DCC1545M Sensitivity to Near Infrared Wavelengths
3 SUPPORTED INFRA-RED ILLUMINATORS RISE BETA uses an adaptation of the pupil-center-corneal-reflection eye-tracking algorithm which works by detecting a corneal reflection (glint) produced on the surface of the cornea by an infra-red illuminator. To detect the glint, the camera needs to have a high degree of sensitivity to Near- Infrared (NIR) wavelengths. The infra-red illuminator should emit infra-red light at a NIR wavelength for which the camera has suitable sensitivity. The overall aim is to produce an approximately circular corneal reflection (glint) on the surface of both the user s eyes. Figure 2 below gives an illustration of a glint produced by the infra-red illuminator. Glint Figure 2: Illustration of Corneal Reflection (Glint) Produced by Infra-Red Illuminator SUPPORTED INFRA-RED ILLUMINATORS: The example given in this guide uses a SIMA 36 LED infra-red light which has LEDs in the 850nm wavelength. From Figure 1, the Thorlabs DCC1545M camera has a Quantum Efficiency of approximately 20% at 850nm wavelengths. A 20% Quantum Efficiency is sufficient when the camera and infra-red illuminator are approximately 60cm (arm s length) from the eyes.
4 USING THE CALIBARTION UTILITY Calibration Utility allows for the creation of calibration files (*.rcal) based upon a specific hardware configuration. The created calibration file can then be loaded into RISE BETA Eye-Tracker. To create a calibration file, users must first enter camera (sensor and lens), infrared illuminator, surface, track-box and (optionally) user calibration properties. 4.1 3D COORDINATE AXIS The Calibration Utility uses a right-handed coordinate system (RHS) with the origin centered on the camera s center of projection. The camera is always considered to be centered on the origin. 4.2 CAMERA PROPERTIES Figure 3: Right Handed Coordinate Axis Calibration Utility allows users to enter certain camera and lens properties. These are listed below: 4.2.1 FX F = Lens Focal Length. FX = F HORIZONTAL_PIXELS SENSOR_WIDTH HORIZONTAL_PIXELS = the camera horizontal resolution. SENSOR_WIDTH = the width of the camera sensor in millimeters.
SETTINGS CAMERA PROPERTIES: FX The camera sensor s dimensions are obtained from the camera specification. In this example the sensor dimensions are 6.66mm 5.32mm. The sensor resolution is 1280 pixels 1024 pixels. The lens focal length is 16mm. FX = 16 1280 6.66 FX = 3075.075 pixels 4.2.2 FY F = Lens Focal Length. FY = F VERTICAL_PIXELS SENSOR_HEIGHT VERTICAL_PIXELS = the camera vertical resolution. SENSOR_HEIGHT = the height of the camera sensor in millimeters. SETTINGS CAMERA PROPERTIES: FY The camera sensors dimensions are obtained from the camera specification. In this example the sensor dimensions are 6.66mm 5.32mm. The sensor resolution is 1280 pixels 1024 pixels. The lens focal length is 16mm. FY = 16 1024 5.32 FX = 3079.699 pixels 4.2.3 CX CX = horizontal coordinate of the optical center of the camera.
CX can be approximated as: CX = HORIZONTAL_PIXELS 2 www. riseeyetracker.com However, more accurate estimates may be possible using camera calibration techniques. SETTINGS CAMERA PROPERTIES: CX The camera sensor properties are obtained from the camera specification. In this example the sensor resolution is 1280 pixels 1024 pixels. CX = 1280 2 CX = 640 pixels 4.2.4 CY CY = Vertical coordinate of the optical center of the camera. CY can be approximated as: CY = VERTICAL_PIXELS 2 However, more accurate estimates may be possible using camera calibration techniques. SETTINGS CAMERA PROPERTIES: CY The camera sensor properties are obtained from the camera specification. In this example the sensor resolution is 1280 pixels 1024 pixels. CY = 1024 2 CY = 512 pixels 4.2.5 HORIZONTAL PIXELS Horizontal Pixels = the horizontal resolution of the sensor.
SETTINGS CAMERA PROPERTIES: Horizontal Pixels The camera sensor properties are obtained from the camera specification. In this example the sensor resolution is 1280 pixels 1024 pixels. Horizontal Pixels = 1280 pixels 4.2.6 VERTICAL PIXELS Vertical Pixels = the vertical resolution of the sensor. SETTINGS CAMERA PROPERTIES: Vertical Pixels The camera sensor properties are obtained from the camera specification. In this example the sensor resolution is 1280 pixels 1024 pixels. Vertical Pixels = 1024 pixels 4.2.7 X ROTATION X Rotation = rotation of camera about X-axis expressed in degrees. SETTINGS CAMERA PROPERTIES: X Rotation If the camera is axis-aligned, then the X Rotation = 0. In our example, the camera is rotated about the X-axis by -10. X Rotation = -10 4.2.8 Y ROTATION Y Rotation = rotation of camera about Y-axis expressed in degrees.
SETTINGS CAMERA PROPERTIES: Y Rotation If the camera is axis-aligned, then the Y Rotation = 0. In our example, the camera is not rotated about the Y-axis. Y Rotation = 0 4.2.9 Z ROTATION Z Rotation = rotation of camera about Z-axis expressed in degrees. SETTINGS CAMERA PROPERTIES: Z Rotation If the camera is axis-aligned, then the Z Rotation = 0. In our example, the camera is not rotated about the Z-axis. Z Rotation = 0 4.3 ILLUMINATOR PROPERTIES Calibration Utility allows users to enter certain illuminator properties. These are listed below: 4.3.1 X X = the illuminator X position with respect to the origin in millimeters. SETTINGS ILLUMINATOR PROPERTIES: X In our example, the illuminator is positioned at coordinates (-75, -18, 10). X = -75.0 mm 4.3.2 Y Y = the illuminator Y position with respect to the origin in millimeters.
SETTINGS ILLUMINATOR PROPERTIES: Y In our example, the illuminator is positioned at coordinates (-75, -18, 10). Y = -18.0 mm 4.3.3 Z Z = the illuminator Z position with respect to the origin in millimeters. SETTINGS ILLUMINATOR PROPERTIES: Z In our example, the illuminator is positioned at coordinates (-75, -18, 10). Z = 10.0 mm 4.4 SURFACE PROPERTIES The Calibration Utility allows users to enter certain properties of the tracking surface. These are listed below: 4.4.1 WIDTH Width = the width of the surface in millimeters. SETTINGS SURFACE PROPERTIES: WIDTH In our example, the surface has dimensions 520 mm by 294 mm. WIDTH = 520 mm 4.4.2 HEIGHT Height = the height of the surface in millimeters.
SETTINGS SURFACE PROPERTIES: HEIGHT In our example, the surface has dimensions 520 mm by 294 mm. HEIGHT = 294 mm 4.4.3 HORIZONTAL PIXELS HORIZONTAL PIXELS = the horizontal tracking resolution of the surface. Note that when the tracking surface is a display screen then HORIZONTAL PIXELS should match the horizontal resolution of the display. However, if the surface is a generic surface such a wall then the HORIZONATL PIXELS should be set to a value that represents the desired horizontal tracking resolution on the surface. SETTINGS SURFACE PROPERTIES: HORIZONTAL PIXELS In our example, the surface is a display screen with resolution 1920 1080. HORIZONTAL PIXELS = 1920 4.4.4 VERTICAL PIXELS VERTICAL PIXELS = the vertical tracking resolution of the surface. Note that when the tracking surface is a display screen then VERTICAL PIXELS should match the vertical resolution of the display. However, if the surface is a generic surface such a wall then the VERTICAL PIXELS should be set to a value that represents the desired vertical tracking resolution on the surface. SETTINGS SURFACE PROPERTIES: VERTICAL PIXELS In our example, the is a display screen with resolution 1920 1080. VERTICAL PIXELS = 1080 4.4.5 X X = the X position of the lower left corner of the surface with respect to the origin in millimeters.
SETTINGS SURFACE PROPERTIES: X In our example, the position of the lower left corner of the display screen with respect to the origin is at coordinates (-260 mm, 40 mm, -185 mm). X = -260.0 mm 4.4.6 Y Y = the Y position of the lower left corner of the surface with respect to the origin in millimeters. SETTINGS SURFACE PROPERTIES: Y In our example, the position of the lower left corner of the display screen with respect to the origin is at coordinates (-260 mm, 40 mm, -185 mm). Y = 40.0 mm 4.4.7 Z Z = the Z position of the lower left corner of the surface with respect to the origin in millimeters. SETTINGS SURFACE PROPERTIES: Z In our example, the position of the lower left corner of the display screen with respect to the origin is at coordinates (-260 mm, 40 mm, -185 mm). Z = -185.0 mm 4.4.8 X ROTATION X ROTATION = rotation of the surface about the X-axis expressed in degrees where the center of rotation is the lower left corner of the surface (X, Y, Z). SETTINGS SURFACE PROPERTIES: X ROTATION In our example, the surface is a display screen aligned to the coordinate axis such the X ROTATION is 0. X ROTATION = 0
4.4.9 Y ROTATION Y ROTATION = rotation of the surface about the Y-axis expressed in degrees where the center of rotation is the lower left corner of the surface (X, Y, Z). SETTINGS SURFACE PROPERTIES: Y ROTATION In our example, the surface is a display screen aligned to the coordinate axis such the Y ROTATION is 0. Y ROTATION = 0 4.4.10 Z ROTATION Z ROTATION = rotation of the surface about the Z-axis expressed in degrees where the center of rotation is the lower left corner of the surface (X, Y, Z). SETTINGS SURFACE PROPERTIES: Z ROTATION In our example, the surface is a display screen aligned to the coordinate axis such the Z ROTATION is 0. Z ROTATION = 0
4.5 TRACK-BOX PROPERTIES The Calibration Utility allows users to enter certain properties of the track-box. The track-box is a segment of the camera s field-of-view within which eye-tracking will take place. These properties are listed below: Y Track-Box x Z Figure 4:Track-Box in which Eye-Tracking Will Take Place. 4.5.1 DISTANCE DISTANCE = the position of the Near-Plane of the track-box with respect to the camera s line of sight. SETTINGS TRACK-BOX PROPERTIES: DISTANCE In our example, the track-box is located at a DISTANCE of 280 mm along the camera s line-of-sight. DISTANCE = 280 mm 4.5.2 DEPTH DEPTH = the depth of the track-box along the camera s line-of-sight.
SETTINGS TRACK-BOX PROPERTIES: DEPTH In our example, the track-box has a DEPTH of 400 mm along the camera s line-of-sight. DEPTH = 400 mm 4.5.3 NEAR RESOLUTION NEAR RESOLUTION = the number of divisions of the width and height of the near-plane of the trackbox. SETTINGS TRACK-BOX PROPERTIES: NEAR RESOLUTION In our example, the with and height of the track-box near-plane will be divided by 30 to create 30 30 = 900 cells. NEAR RESOLUTION = 30 4.5.4 FAR RESOLUTION FAR RESOLUTION = the number of divisions of the width and height of the far-plane of the track-box. SETTINGS TRACK-BOX PROPERTIES: FAR RESOLUTION In our example, the with and height of the far-plane of the track-box will be divided by 60 to create 60 60 = 3,600 cells. FAR RESOLUTION = 60 4.5.5 DEPTH RESOLUTION DEPTH RESOLUTION = the number of divisions of the depth of the track-box. SETTINGS TRACK-BOX PROPERTIES: DEPTH RESOLUTION In our example, the depth of the track-box will be divided by 60 to create 60 track-box divisions. DEPTH RESOLUTION = 60
4.6 USER CALIBRATION PROPERTIES The Calibration Utility allows users to define the number of calibration points to include in the optional user-calibration. These properties are listed below: 4.6.1 COLUMNS COLUMNS = the number of calibration points on a row. SETTINGS USER CALIBRATION PROPERTIES: COLUMNS In our example, the user calibration will use 4 rows of calibration points with each row having 4 columns. COLUMNS = 4 4.6.2 ROWS ROWS = the number of rows of calibration points. SETTINGS USER CALIBRATION PROPERTIES: ROWS In our example, the user calibration will use 4 rows of calibration points with each row having 4 columns. ROWS = 4 4.7 CREATING A CALIBRATION FILE After entering the properties for the camera, illuminator, surface, track-box and (optionally) user calibration, it is possible to create a calibration file (*.rcal) by clicking the CALIBRATE button.
Click Calibrate Button Figure 5: Creating a System Calibration CREATING SYSTEM CALIBRATION: CALIBRATE In our example, the Calibration Utility Settings are as show in Figure 6, Figure 7 and Figure 8.
Figure 6: Calibration Utility Configured for Desktop Eye-Tracking Figure 7: User Calibration Settings
Figure 8: Creating a Calibration File with Calibration Utility www. riseeyetracker.com
5 USING RISE BETA Select Camera Track Gaze User Calibration Smooth Gaze Data Log Gaze Data Export Gaze Data Launch Calibration Utility 5.1 MENU 5.1.1 FILE Figure 9: RISE BETA Eye-Tracker 5.1.1.1 LOAD SETTINGS Load eye-tracker settings from previously saved file. 5.1.1.2 SAVE SETTINGS AS Save current eye-tracker settings file (*.rset) to disk. 5.1.1.3 LOAD SYSTEM CALIBARTION Load system calibration file (*.rcal). 5.1.1.4 LOAD USER CALIBARTION Load user calibration file (*.rucal). 5.1.1.5 SAVE USER CALIBRATION AS Save current user calibration as (*.rucal) file to disk. 5.1.1.6 LOAD DETECTION CASCADE Load XML detection cascade file.
5.1.1.7 LOAD USER VIDEO Load a user video (*.avi) file. 5.1.1.8 EXIT Exit RISE BETA, 5.1.2 CAMERA 5.1.2.1 SELECT CAMERA Launch the camera selection dialog window. 5.1.2.2 START CAMERA Start previously stopped camera. 5.1.2.3 STOP CAMERA Stop camera. 5.1.2.4 START RECRODING Start recording user video as (*.avi) file. 5.1.2.5 STOP RECORDING Stop recording user video. 5.1.3 USER CALIBRATION 5.1.3.1 DISPLAY CALIBRATION Launch user calibration window for display screen. 5.1.3.2 SURFACE CALIBRATION Launch user calibration window for generic surface. 5.1.4 TRACKING 5.1.4.1 START TRACKING Start gaze tracking. 5.1.4.2 STOP TRACKING Stop gaze-tracking. 5.1.4.3 SMOOTH TRACKING Perform Gaussian smoothing on gaze data. 5.1.4.4 SHOW CROSSHAIR Toggle gaze-tracking crosshair on and off. 5.1.4.5 USE SECONDARY MONITOR Toggle use of secondary screen on and off. 5.1.5 LOGGING 5.1.5.1 LOG CSV GAZE DATA Start logging gaze data as (*.csv) file. 5.1.5.2 LOG XML GAZE DATA Start logging gaze data as (*.xml) file.
5.1.5.3 PAUSE LOGGING Pause logging gaze data. 5.1.5.4 STOP LOGGING Stop logging gaze data and prompt user to save gaze data log to disk. 5.1.6 SETTINGS Launch eye-tracker settings dialogue window. 5.1.7 ABOUT Launch the about dialog window. 5.2 TOOLBAR 5.2.1 SELECT CAMERA 5.2.2 TRACK GAZE Launch the camera selection dialog window. Toggle gaze-tracking on and off. Launch the user calibration window. Note: the user calibration window will only launch if the current selected tracking screen (primary or secondary) has the same horizontal and vertical resolution as the specified by HORIZONTAL PIXELS (Section 4.4.3) and VERTICAL PIXELS (Section 4.4.4) in the CALIBRATION UTILITY when generating the loaded calibration file (*.rcal). 5.2.3 SMOOTH GAZE DATA Perform Gaussian smoothing on gaze data. 5.2.4 LOG GAZE DATA Toggle gaze data logging on and off. 5.2.5 EXPORT GAZE DATA Save gaze data to disk. 5.2.6 LAUNCH CALIBRATION UTILITY Launch the Calibration Utility.
Figure 10: RISE BETA Eye-Tracker Connected to Thorlabs DCC1545M Camera with a 16mm Focal Length Lens 5.3 RISEBETA SETTINGS 5.3.1 CASCADE SETTINGS RISE BETA will detect the user s eyes using cascade files. RISE BETA requires a cascade file for the left and right eyes, both eyes, and nose. Suitable cascade files are obtained with the OpenCV image processing library and are available for download from our website. www.riseeyetracker.com/resources/ To load the cascade files, click File->Load Detection Cascade and navigate to the folder where the OpenCV Cascades files were downloaded and select all the cascade files.
Cascades Assigned to Left Eye Loaded Cascades Cascades Assigned to Right Eye Assign/Unassigned Cascade Cascades Assigned to Eye Pair Cascades Assigned to Nose Figure 11: RISE BETA Cascade Settings RISE BETA SETTINGS: CASCADEs In our example, load the cascade files by clicking File->Load Detection Cascade and navigate to the folder where the OpenCV cascades were downloaded and select the following cascade files: haarcascade_mcs_lefteye haarcascade_mcs_righteye haarcascade_eye_tree_eyeglasses.xml haarcascade_mcs_eyepair_big.xml haarcascade_mcs_nose.xml Once loaded the cascade files are assigned as presented in Figure 12 below.
Figure 12: RISE BETA Loaded with OpenCV Cascades www. riseeyetracker.com
5.3.2 DETECTION SETTINGS Figure 13: Detection Settings 5.3.2.1 MINIMUM EYE WIDTH MINIMUM EYE WIDTH = the minimum width of an eye in pixels. Eyes with a width less than MINIMUM EYE WIDTH will not be detected. SETTINGS DETECTION PROPERTIES: MINIMUM EYE WIDTH Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM EYE WIDTH = 130 pixels 5.3.2.2 MINIMUM EYE HEIGHT MINIMUM EYE HEIGHT = the minimum height of an eye in pixels. Eyes with a height less than MINIMUM EYE HEIGHT will not be detected.
SETTINGS DETECTION PROPERTIES: MINIMUM EYE HEIGHT Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM EYE HEIGHT = 90 pixels 5.3.2.3 MINIMUM EYE PAIR WIDTH MINIMUM EYE PAIR WIDTH = the minimum width of a pair of eyes in pixels. An eye pair with a width less than MINIMUM EYE PAIR WIDTH will not be detected. SETTINGS DETECTION PROPERTIES: MINIMUM EYE PAIR WIDTH Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM EYE PAIR WIDTH = 460 pixels 5.3.2.4 MINIMUM EYE PAIR HEIGHT MINIMUM EYE PAIR HEIGHT = the minimum height of a pair of eyes in pixels. An eye pair with a height less than MINIMUM EYE PAIR HEIGHT will not be detected. SETTINGS DETECTION PROPERTIES: MINIMUM EYE PAIR HEIGHT Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM EYE PAIR HEIGHT = 80 pixels 5.3.2.5 MINIMUM NOSE WIDTH MINIMUM NOSE WIDTH = the minimum width of a nose in pixels. Noses with a width less than MINIMUM NOSE WIDTH will not be detected.
SETTINGS DETECTION PROPERTIES: MINIMUM NOSE WIDTH Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM NOSE WIDTH = 150 pixels 5.3.2.6 MINIMUM NOSE HEIGHT MINIMUM NOSE HEIGHT = the minimum height of a nose in pixels. Noses with a height less than MINIMUM NOSE HEIGHT will not be detected. SETTINGS DETECTION PROPERTIES: MINIMUM NOSE HEIGHT Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM NOSE HEIGHT = 120 pixels 5.3.2.7 MINIMUM PUPIL DIAMETER MINIMUM PUPIL DIAMETER = the minimum diameter of a pupil in pixels. Pupils with a diameter less than MINIMUM PUPIL DIAMETER will not be detected. SETTINGS DETECTION PROPERTIES: MINIMUM PUPIL DIAMETER Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM PUPIL DIAMETER = 14 pixels 5.3.2.8 MAXIMUM PUPIL DIAMETER MAXIMUM PUPIL DIAMETER = the maximum diameter of a pupil in pixels. Pupils with a diameter greater than MAXIMUM PUPIL DIAMETER will not be detected.
SETTINGS DETECTION PROPERTIES: MAXIMUM PUPIL DIAMETER Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MAXIMUM PUPIL DIAMETER = 26 pixels 5.3.2.9 MINIMUM GLINT DIAMETER MINIMUM GLINT DIAMETER = the minimum diameter of a glint in pixels. Glints with a diameter less than MINIMUM GLINT DIAMETER will not be detected. SETTINGS DETECTION PROPERTIES: MINIMUM GLINT DIAMETER Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MINIMUM GLINT DIAMETER = 1 pixel 5.3.2.10 MAXIMUM GLINT DIAMETER MAXIMUM GLINT DIAMETER = the maximum diameter of a glint in pixels. Glints with a diameter greater than MAXIMUM GLINT DIAMETER will not be detected. SETTINGS DETECTION PROPERTIES: MAXIMUM GLINT DIAMETER Our example uses a THORLABS DCC1545M camera with a 16mm focal length lens for desktop eyetracking where the camera is approximately 60cm (arm s length) from the eye. MAXIMUM GLINT DIAMETER = 14 pixels 5.3.2.11 INTERPUPILARY DISTANCE INTERPUPILARY DISTANCE = the distance in millimeters between the center of the pupil in the left eye to the center of the pupil in the right eye.
SETTINGS DETECTION PROPERTIES: INTERPUPILARY DISTANCE Our example assumes that the INTERPUPILARY DISTANCE is 65 mm. INTERPUPILARY DISTANCE = 65 mm 5.3.2.12 DETECTION SCALE DETECTION SCALE = the amount by which camera/video images will be scaled before eye/nose detection takes place. A DETCTION SCALE < 1 will reduce the size of the image while a DETECTION SCALE > 1 will increase the size of the image before detection takes place. SETTINGS DETECTION PROPERTIES: DETECTION SCALE Our example assumes that the DETECTION SCALE = 0.25 such that camera/video images are reduced to 25% of their original size before detection. DETECTION SCALE = 0.25 5.3.2.13 DU DU = the horizontal pixel displacement applied to the estimated gaze coordinates. DU can be used for uniform drift correction where estimated gaze coordinates need to be displaced horizontally on the tracking surface. SETTINGS DETECTION PROPERTIES: DU Our example assumes that the DU = 0 such that there is no horizontal drift correction applied to estimated gaze coordinates on the tracking surface. DU = 0
5.3.2.14 DV DV = the vertical pixel displacement applied to the estimated gaze coordinates. DV can be used for uniform drift correction where estimated gaze coordinates need to be displaced vertically on the tracking surface. SETTINGS DETECTION PROPERTIES: DV Our example assumes that the DV = 0 such that there is no vertical drift correction applied to estimated gaze coordinates on the tracking surface. DV = 0 5.3.2.15 FLIP CAMERA IMAGE FLIP CAMERA IMAGE = checkbox indicating whether the image received from the camera needs to be flipped vertically (turned upside down). This is because camera images received using the DirectShow and Media Foundation interfaces are sometimes flipped vertically compared to the image received using the camera s native driver. SETTINGS DETECTION PROPERTIES: FLIP CAMERA IMAGE Our example connects to the THORLABS DCC1545M camera via the Microsoft DirectShow interface and images received do not need to be flipped vertically. FLIP CAMERA IMAGE = unchecked
5.4 CREATING A USER CALIBRATION The Calibration Utility allows users to define the number of calibration points to include in the optional user calibration. Once the system calibration file (*.rcal) is loaded into RISE BETA, there are two possible ways to launch a user calibration depending upon whether the surface is a connected display screen or a generic surface. 5.4.1 DISPLAY SCREEN USER CALIBRATION From the menu select User Calibration -> Display Calibration. Alternatively, click the User Calibration button on the toolbar. The user Calibration window for a display screen will open provided the currently selected display (see Section 5.1.4.5) has the same resolution as in the System Calibration file (*.rcal) created with the Calibration Utility. Figure 14 below shows an example of a User Calibration window. Figure 14: User Calibration Window for Display Screen To calibrate the user must focus his/her gaze on a pink calibration target and then click the target with the mouse pointer. The user must maintain focus on the center of the calibration target for a minimum of one second then click the target a second time. The calibration target will then become disabled. The user must repeat for all targets. Figure 15 below shows a typical user calibration.
Figure 15: User Calibration Window for Display Screen with Typical Calibration Results 5.4.2 GENERIC SURFACE USER CALIBRATION From the menu select User Calibration -> Surface Calibration. The user calibration window for generic surfaces will open. Figure 16 below shows an example of a User Calibration window.
Figure 16: User Calibration Window for Generic Surface To calibrate the user must focus his/her gaze on the center of a calibration target on the surface and click on the corresponding pink calibration target in the calibration window. This requires that the coordinates of the calibration targets specified within the Calibration Utility when creating the system calibration file (*.rcal) are accurately marked on the surface. The user must maintain focus on the center of the calibration target on the surface for a minimum of one second then click the pink calibration target within the calibration window a second time. The calibration target will then become disabled. The user must repeat for all surface targets. Figure 17 below shows a typical user calibration for a surface.
Figure 17: User Calibration Window for Generic Surface with Typical Calibration Results