At Charles de Gaulle Airport while waiting to go through security, there is a monitor describing the security protocol at the airport. The instructions on the 52’’ monitor are impossible to read and have awful contrast. See the image below, which is taken using a camera with a zoom. The task was to better convey the instructions to those in line by redesigning the display.
In addition, the birds-eye or top-down layout of the security check is as follows. The monitor is 10 feet off of the ground and the width of the room is 60x50 feet. Note that there are two lines. The approximate time from that location to the front of the line is given.
For 20/20 vision, the Human Factors Design Standard (HFDS) recommends that the height of characters occupy a visual angle of 16 to 24 minutes of arc.
In order to suffice the above requirement, visual angle of 19.10 minutes of arc is chosen. This translates to 1 inch of text size for every 180 inches, i.e., 15 feet of viewing distance. The following table calculates the required font size according to the viewing distance, keeping the visual angle constant.
Assumptions for calculation:
Monitor Resolution: 1920 x 1080
Minutes of Arc: 19.1
|Total Pixels||Font Size|
Considering the content to be displayed and the legibility of the content when viewed from a distance, I decided to split the content in 3 slides in all. Following is the content of the slides:
- Additional information
This content split makes the screen more legible as the content size can be scaled up. Grouping relevant content together reduces the dependence on user’s long-term memory.
Font size of 197 is used for the title. This will ensure that even from a distance of 60 feet, user will be able to read the text.
Font size of 98 is used for the content. This will ensure that even from a distance of 30 feet, user will be able to read the text. This is half the distance of the total line and ensures that the text remain legible for the users closest to the screen to the users till a distance of 30 feet.
Info Requirement: User needs to know what are the important tasks – what is allowed and what isn’t allowed.
Font size of 65 is used for the content. This will ensure that even from a distance of 20 feet, user will be able to read the text. This is a third of the distance of the total line and ensures that the text remain legible for the users closest to the screen to the users till a distance of 20 feet.
Info Requirement: User needs to know what are the details of the tasks – specifications of tasks.