ETPhone App for ETVision

Eye Tracker Systems Manual

ETPhone for use with ETVision

MANUAL VERSION 1.1

November 2022

techsupport@argusscience.com

Web site: www.argusscience.com

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Table of Contents

1 GENERAL DESCRIPTION ......................................................................................................................... 3

2 INSTALLATION .......................................................................................................................................... 4

3 ETPHONE OPERATION ............................................................................................................................. 5

3.1 Display Auto Calibration Target .............................................................................................................. 5

3.2 Establish WiFi communication between ETPhone and the ETVision Controller ........................................ 5

3.3 Monitor ETVision cameras and performance ............................................................................................ 7

3.4 Auto Calibrate ......................................................................................................................................... 7

3.5 Set “Profile” name .................................................................................................................................. 7

3.6 Control SD card recording ....................................................................................................................... 8

3.7 Record eyetracking data files on the iPhone ............................................................................................. 8

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1 General Description

ETPhone is an iPhone app that can assist in the use of the Argus Science ETVision eyetracker. It can

be used simply to display the AutoCalibration target used by ETVision, but can also be used to

substitute for functions normally performed by the ETVision PC when it is not convenient for the PC

to be in WiFi range.

In addition to simply displaying the ETVision AutoCalibration target, the ETPhone app can:

• Establish a WiFi connection to the ETVision Controller.

• Display eye and scene camera images with superimposed eye feature recognition overlays

and a superimposed point-of-gaze cursor.

• Start and stop SD card recording by the ETVision Controller.

• Perform Auto Calibration and record 30 Hz digital data, as well as scene camera video files to

iPhone memory.

If using ETVision in an environment where it is not convenient to bring the ETVision PC, ETPhone

can be used to verify that head mounted cameras are properly aimed, that eye features will be properly

recognized, and that a subject auto calibration will be successful before starting SD card recording on

the Controller. It can also be used to adjust the camera gain and compression ratio, and subject head

phone and microphone volumes, if necessary. The video data recorded on the SD card can later be

played back through the ETVision PC to produce 180 Hz eye tracking data (see ETVision manual,

section 7.8.3).

Alternately, if only 30 Hz data is required (rather than 180 Hz data) and recording period will be

reasonably short, data can be recorded directly on the iPhone by the ETPhone app.

The ETPhone app will run on iPhone 8 or above with IOS 16.0 or above.

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2 Installation

Search for “ETPhone” on the iPhone App Store.

Touch the download icon to download and install the app.

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ETPhone

Operation

3.1 Display Auto Calibration Target

Open the ETPhone App and touch the calibration target icon. A full size calibration target image will

fill the iPhone screen as shown on the right image below. Touch the center of large target to return to

the home screen.

ETPhone home screen (no Wi-Fi connection) Full screen Auto Calibration target

3.2 Establish WiFi communication between

ETPhone

and the

ETVision

Controller

• Close the ETPhone app if already opened.

• Be sure that the ETVision controller is connected to the head mounted optics, and that it is

powered on (green power light if controller is connected to a power outlet; blue power light if

running on battery power).

• Be sure no other device is connected to ETVision controller (the controller will only connect to

one device at a time).

Auto

Calibration

Icon

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• Go to iPhone “Settings > Wi-Fi”. If the phone is within Wi-Fi range of the ETVision

Controller, the Networks list should include the ETVision serial number listed on the

Controller back panel label. Touch this item to connect. If asked for a password, use the

password listed on the Controller back panel label. A check mark will appear next to the

network name to indicate a successful connection.

• Close "Settings" and open the ETPhone app. An ETVision interface screen should appear

showing the eye and scene images from the head mounted cameras.

Holding the Phone horizontally produces the display shown below. This display can be scrolled to

expose the additional items shown at the bottom of the vertical display.

Left eye

video

Right eye

video

Eye camera gain

Eye camera quality

Scene camera quality

Set Profile button

Profile name

SD card record

iPhone record

Scene Video

Microphone Gain: 15

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3.3 Monitor

ETVision

cameras and performance

The Eye image displays show the same feature recognition overlays for the pupil, corneal reflections,

and eyelid positions as the standard ETVision PC display. These are explained in section 7.8 of the

ETVision manual. The slider under the left eye image controls eye camera gain for both eyes (default

= 10), and the slider under the right eye image controls the quality ratio for both eye cameras (default

= 70).

The slider under the scene camera image controls image quality (default = 70). If the eye features are

being successfully recognized, the scene image will show a superimposed point-of-gaze cursor. On

ETPhone, the point of gaze cursor is always a green circle as shown on the sample images. Unlike the

cursor on the ETVision PC application, it is not configurable.

The Microphone Gain slider can be used to adjust the volume of audio that will be picked up by the

head gear microphone and recorded on either SD card recordings or phone recordings.

3.4 Auto Calibrate

To perform a subject Auto Calibration, touch the target icon at the top of the ETPhone screen to

produce the full screen target display. Hold the target still at about an arms length in front of the

subject (or have the subject hold it themselves), and ask the subject to fixate the center of the target.

When ETPhone detects that calibration has been successful (target recognized in scene camera image,

and eye position stable for about a second) the full screen target will disappear and the standard

display will reappear. Touching the center of the full screen target will cause the standard screen to

return even if the calibration criteria have not been met.

Calibration results will be reflected in 30 Hz recordings saved on the iPhone, but will not be saved by

SD card recordings.

In the case of SD card recordings, only the raw video information is saved. The calibration must be

done during the off-line process when the SD recordings are played back through the ETVision PC

application. Nevertheless, if recording to an SD card, it is recommended that an ETPhone Auto

Calibration be done after SD card recording begins. This section of video data can then be used to

do an Auto Calibration (or manual single point calibration) during off- line SD card file playback.

Auto Calibration is the only subject calibration procedure available on ETPhone. Manual and multi

point calibration procedures available on the ETVision PC application are not supported by ETPhone.

Assuming appropriate video data was collected (periods where the subject was know to be fixating

target points) these options will still be available during SD card file playback using the ETVision PC

application.

3.5 Set “Profile” name

Files recorded either by the controller on an SD card or directly on the iPhone will have a file name

consisting of the “Profile” name followed by a date and time code corresponding to the controller

clock value when recording begins. To set the “Profile” name type the desired file name in the

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“Profile” name field on the ETPhone app, and touch the profile symbol to the right of the name field

to set the profile name.

3.6 Control SD card recording

To control SD card recording with ETPhone, first establish a Wi-Fi connection as previously

described. If an SD card is detected by the ETVision Controller the SD card record button on

ETPhone will be active. If this button is “grayed out” ensure that an SD card is correctly inserted in

the ETVision Controller. The SD card record button should then appear active.

Start recording by touching the SD card record button. An SD card file, with a name consisting of the

profile name followed by a date and time code, will start recording, and the SD card record button will

change to a pause symbol. The iPhone record button will be disabled, and turn gray. It is not

possible to simultaneously record both to an SD card and directly to the phone.

As mentioned in the previous section, it is recommended that an ETPhone Auto Calibration be done

after SD card recording begins. This section of video data can then be used to do an Auto Calibration

(or manual single point calibration) during off- line SD card file playback.

To stop recording to the SD, touch the pause symbol. The button will revert to showing the record

symbol (and the phone record symbol will once again become active). To record another file to the

SD card, touch the SD card record button again. A new file will begin recording. Each file recorded

will be named with the current profile name and a time code corresponding to the Controller clock

value when recording started. After each recording starts, it is recommended that the subject fixate the

Auto Calibration target, as previously described, to provide a period of video data that can be used for

Calibration during SD card file playback.

To process recorded SD card files and create eye-tracking data, follow instruction in section 7.8.3 of

the ETVision manual.

3.7 Record eyetracking data files on the iPhone

A fixed digital data set along with the scene camera video can be recorded 30 times per second

directly on an iPhone running ETPhone. Note: Rather than recording directly to the iPhone, we

normally recommend recording to the SD card for subsequent processing or directly to a PC since

these options produce data with the most robust feature recognition and highest update rate (180 Hz).

If the subject is not already calibrated, perform a subject Auto Calibration as previously described in

section 3.4.

To start recording 30 Hz data to the iPhone, touch the phone record button. The record symbol will

change to a pause symbol. Even if there is an SD card in the controller, the SD card record button will

become inactive and will turn gray when recording to the phone begins (it is not possible to

simultaneously record both to an SD card and directly to the phone). Stop recording by touching the

pause button on ETPhone.

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A digital data file and a scene camera video file will be recorded, both at 30Hz. Both files will have a

file name consisting of the Profile name followed by a date and time code. The data file will have a

“csv” extension, and the video file will have a “mov” extension. The data file format will be the csv

file format described in the ETVision manual, but with 30 samples per second rather than 180 samples

per second.

The size of the digital data file will usually be just over 8 KB/sec. The size of the video file will

depend on scene camera “quality” value and video content, but will usually be about 0.8 MB/sec.

The data items recorded on the digital data file are listed below.

Time

Status

overtime_count

mark_value

CU_video_field_num

left_pupil_pos

right_pupil_pos

left_pupil_diam

right_pupil_diam

left_pupil_height

right_pupil_height

left_ellipse_angle

right_ellipse_angle

left_eyelid_upper_vert

right_eyelid_upper_vert

left_eyelid_lower_vert

right_eyelid_lower_vert

left_cr_pos

right_cr_pos

left_cr_diam

right_cr_diam

left_cr2_pos

right_cr2_pos

left_cr2_diam

right_cr2_diam

horz_gaze_coord

vert_gaze_coord

vergence_angle

verg_gaze_coord

left_eye_location

right_eye_location

left_gaze_dir

right_gaze_dir

An explanation of each data item can be found in Appendix C of the ETVision manual.

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To view files recorded by ETPhone, open the “Files” app on the iPhone. Under “Browse”, select “On

my iPhone”, then select the “ETPhone” folder to see the list of recorded ETVision files. Swipe a file

name to the left and touch the “trash” icon to delete the file. Touch the file name to view the file; and

then touch the “send” icon to send files to other devices via email, air drop, etc. (Note that some files

might be too large to send via email). Alternately, connect the iPhone to a PC and use the PC iTunes

app to transfer files.

Files recorded by ETPhone can be processed by ETAnalysis in the usual fashion, but of course need to

be first transferred to a PC running ETAnalysis. Because of the low temporal resolution (30 Hz

update rate), data recorded on ETPhone is usually not appropriate for the saccade analysis available on

ETAnalysis.