Enhancing your AOI analysis: A helpful tool for researchers

Precise definition and management of Areas of Interest (AOIs) is often crucial for accurate analysis of eye tracking data. While Tobii Pro Lab already offers powerful functionality, some researchers may have the need for more efficient comparison of AOI sizes and coverage across multiple files, as well as improved customization of labels for clearer and easier reporting on AOI definitions specifically tailored for publication and commercial presentations. 

To help with that, I created a small complementary tool I called AOI Area Calculator that works with AOI files exported from Tobii Pro Lab. You can export AOIs by right-clicking them in Pro Lab and selecting "Export AOIs." These exported files can be shared across projects or with colleagues, but they can also be used for deeper analysis outside Pro Lab. The AOI Area Calculator tool reads this data (.aois files) and lets you compare, analyze, and visualise AOIs beyond what Tobii Pro Lab currently offers.

How can this tool help with your analysis? 

I built this tool with a little help from ChatGPT (because not all of us are developers!) While this tool was initially built with researchers in mind, it's also meant to showcase what's possible when working with Exported AOI data from Tobii Pro Lab. Whether you're exploring its capabilities out of curiosity or looking to build something new, the tool serves as a starting point for experimentation and innovation. That´s why the source code is available and open-source. 

This tool is designed to help researchers more effectively check, analyze, and visualize AOIs and their labels. It tackles a common challenge: understanding how much of the stimulus each AOI covers — whether in pixels or as a percentage. This matters because attention tends to be naturally biased toward larger areas, which can skew gaze metrics if not accounted for.

By providing this coverage data, the tool allows researchers to weigh their metrics more accurately. Another key feature is the flexibility it offers in formatting and positioning AOI labels. Users can easily adjust label placement, font, size, and color, making it much easier to create clear, uncluttered visuals for presentations or reports. 

Researchers may ask: 

• How much of the stimulus does each AOI cover? 

• Can I adjust AOI labels for better presentation use? 

• How do I ensure consistency across AOIs? 

This tool was created to help answer those questions. 

Key Features 

• 🔄 Batch processing of multiple AOI files for side-by-side comparisons 

• 📏 Calculates AOI size and coverage in both pixels and percentage 

• 📊 Summarizes total AOI coverage per file 

• 🔍 Sort and inspect AOIs by name or file across conditions 

• 📤 Export results to Excel, with one sheet per AOI file 

• 🌅 Preview AOIs on the original snapshot 

• 📄 Adjust label position, font, size, and color, drag labels even outside the image 

• 📸 Save clean and scaled visuals as PNG or JPG for reports and publications 

Note: This tool is designed for static AOIs only. Dynamic AOIs vary in shape and size over time and are not currently supported. 

Try it out 

Download the tool. It’s a self-executable file, no installation or dependencies required, but it´s designed for Windows. Defender may warn about running this (select “Run anyway”) as it´s not an officially signed software, this is expected behavior. The Python script is fully Open Source and included in the ZIP file for inspection and modification or other use of the code.  

Please read the included ReadMe file for full instructions.  

Keep in mind: This is an experimental tool, not an official Tobii product. While it’s available for use, we can’t offer formal support, and users should be mindful of potential bugs. 

Takeaways and tips 

This tool is especially useful for researchers who want to: 

• Compare AOIs across different conditions 

• Weight gaze metrics based on AOI size 

• Create clear, customizable AOI visuals for presentations or publications 

It’s a small addition to your toolkit, but one that can make a big difference in allowing you more control over how to interpret and communicate your findings. 

And if you’re new to AOIs or want to sharpen your skills, don’t forget:
Tobii Academy has several great courses to help you get started!