What The Polygraf is?

Polygraf was primarily developed to provide an access for hearing and visually impaired students of university (consequently, it is typically used at lectures and seminars). However, given the fact that requirements for a technical equipment on a location are minimal, it can also be used outside of school facilities (such as at presentations and business meetings) when participation of persons with the disabilities is expected. Polygraf enables:

  1. Visualisation of the synchronous transcription (speech-to-text) on handheld displays (tablet, mobile phone, notebook). Service is primarily focused on the users with hearing impairment dependent on speech-to-text visualization.
  2. Presentation screen mirroring (on handheld displays) enhancing the readability for users with visual impairment.

Polygraf is based on a technology which can be used independently of commonly considered technical parameters of an environment such as wireless network signal coverage. It only requires access to electricity. All this makes it quite a universal system and as experience showed not only students with disabilities can take an advantage of the service but any users can do, as well.

Description of the System

  1. It does NOT require Internet connection nor its own server.
  2. It uses mobile devices what secures a basic user comfort:
    • a touch-screen user interface,
    • long battery life,
    • portability comfort,
    • quick and simple start-up.
  3. It enables customizable view of the content:
    • text reports and closed captions: font family, size and colour, line-spacing;
    • presentation screen mirroring: magnification, color-inverting.
  4. It is compatible with commonly used soft- and hardware:
    • MS Windows environment used often by speech-to-text reporters;
    • any device (as a source of presentation) connected through VGA or DVI interface.
  5. The software solution also enables to show a report as dynamic closed captions on a speaker’s computer and thus immediately supplement the speaker’s presentation when there is one.
  6. The content can be displayed for individual purpose in hand and for public purposes on a large screen using the handheld device.
  7. It is possible to send text messages from handheld displays to a reporter’s laptop, such as technical comments, further questions about contents of a report (the reporter is the only receiver of the message), or the reporter’s own contributions to a current discussion (here, the reporter’s role is a mediator among debating partners).

Uniqueness of Polygraf

  • simple and quick technical preparation
  • independence on a local technical infrastructure as well as on presentation technologies
  • speech-to-text report is synchronized with a reporter’s typing
  • basic parameters of a reported text are customizable (font size, colours) 
  • a possibility of a basic two-way communication (the interface enables user to send text messages)
  • magnification of the presentation content and adding subtitles
  • compatible with handheld devices of users
  • nearly real-time update of the mirroring without consuming too much battery power

Components of Polygraf


  • A laptop or PC with the Microsoft Windows operating system. This computer is for the text reporter.
  • A screen capturing device for the presenting speaker – a broadcasting device capturing the video signal and providing it, apart from the output for data projectors, through network interface. (Optionally, this hardware can be substituted by the software – Polygraf Broadcaster.)
  • WiFi access point to create a wireless network connecting all devices together and transfer the content among them. There is no need of Internet connectivity for this wireless network.
  • Any handheld device with iOS or Android operating system (typically, a smartphone, tablet or laptop). This device works as a handheld display for users to follow a report and/or mirrored screen.


ikona Polygraf WriterPolygraf Writer (for the reporter’s computer) 
A special text editor for Microsoft Windows; its purpose is to write and “share” the text report to the users’ devices.

Polygraf - ikonaPolygraf (for the users’ handheld devices) 
It handles the reception of the text report as well as the mirrored screen and it continuously updates and displays according to the user’s custom setting.

Polygraf Broadcaster - ikonaPolygraf Broadcaster (for the speaker’s computer) 
The application captures the screen of speaker’s computer and provides it through network to the users’ devices. (This software can be substituted by the hardware broadcasting device.)

Polygraf Caption - ikonaPolygraf Captions (for the speaker’s computer) 
An optional application to display the reported text in the form of continuously updated subtitles displayed as closed captions, which can be attached to a speaker’s presentation. The application will soon be replaced with a multi-purpose application Polygraf for Windows.


Polygraf Writer (a component for the reporter’s computer)
for Windows 7/8/10/11 operating system

Polygraf Writer for Polygraf Online (a component for the reporter’s computer)
for Windows 7/8/10/11 operating system

Polygraf (a component for the users’ handheld devices)
for iOS operating system (e.g. Apple iPad, iPod, iPhone)
for Android operating system (e.g. tablets and smartphones with this operating system)

Polygraf Broadcaster (for the speaker’s computer)
for Windows 7/8/10/11 operating system
for mac OS operating system
(These applications have been developed with the assistance of the Czech Radio Endowment Fund.)


Information leaflet on Polygraf system: English, Czech