Apr 10, 2026

Comparative Assessment protocol of readability Using RTI and VRTI

DOI
https://dx.doi.org/10.17504/protocols.io.kqdg3m1mzl25/v1
  • Luisa Ammirati1,
  • Alice Bordignon1,
  • Michela Contessi1,
  • Francesca Fabbri1
  • 1University of Bologna
Francesca Fabbri
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DOI: https://dx.doi.org/10.17504/protocols.io.kqdg3m1mzl25/v1
Protocol Citation: Luisa Ammirati, Alice Bordignon, Michela Contessi, Francesca Fabbri 2026. Comparative Assessment protocol of readability Using RTI and VRTI. protocols.io https://dx.doi.org/10.17504/protocols.io.kqdg3m1mzl25/v1
License: This is an open access  protocol  distributed under the terms of the  Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: March 25, 2026
Last Modified: April 10, 2026
Protocol  Integer ID: 313892
Keywords: Reflectance Transformation Imaging, RTI, Virtual Reflectance Transformation imaging, VRTI, cultural heritage, assessment, readability of paleontological footprint, comparative assessment protocol of readability, impact of reflectance transformation imaging, reflectance transformation imaging, paleontological footprint, readability, vrti, using rti, rti, virtual rti, annotation process, assessment, comparative assessment protocol, vrti this protocol, generated annotation
Abstract
This protocol describes a workflow for assessing the impact of Reflectance Transformation Imaging (RTI) and Virtual RTI (VRTI) on the readability of paleontological footprints. The procedure replicates the annotation process of a domain expert and compares participant-generated annotations against a predefined ground truth.
Materials
**Hardware**
- Tablet with RTI Viewer installed
- iPad with Apple Pencil with Adobe Photoshop

**Software**
- RTI Viewer
- RelightLab
- Adobe Photoshop

**Data**
- RTI and VRTI (.ptm) files of paleontological footprints
Ground truth definition
Material required:
  • 1 Ipad with apple pencil
  • Adobe Photoshop
Software
Adobe Photoshop
NAME
Adobe
DEVELOPER
https://www.adobe.com/products/photoshop.html
SOURCE LINK

Media preparation:

  • Capture two snapshots of the RTI and VRTI footprint surveys in RTI viewer
  • Spatially align the images to ensure pixel-level correspondence
  • Place the aligned images onto a neutral background within the Adobe Photoshop workspace.
  • Create a preconfigured Photoshop workspace in which the footprint image is set as a locked background layer.

Open the RTI snapshot in Adobe photshop, ask the domain expert to draw in two separate levels with 3 px trait:
  • perimeter of the footprint in green (0, 255, 0)
  • footprint detail fingerpad of the second finger in yellow (255, 255, 0)


Ground truth by domain expert

Experiment Set up
Material required for the experiment:

  • 2 Android tablets-Station A
  • 2 iPads with 2 Apple Pencils- Station B

Station A preparation

Devices: 2 Android tablet

  • Tablet 1: open RTI file on RTI viewer
Software
Relight
NAME
CNR-ISTI
DEVELOPER
http://github.com/cnr-isti-vclab/relight/releases
REPOSITORY
https://vcg.isti.cnr.it/vcgtools/relight/
SOURCE LINK

RTI footprint in rti viewer
Tablet 2: open VRTI file on RTI viewer

VRTI footprint in rti viewer

Station B preparation:

  • On iPad 1, open the workspace containing the RTI footprint.
  • On iPad 2, open the workspace containing the VRTI footprint.
Software
Adobe Photoshop
NAME
Adobe
DEVELOPER
https://www.adobe.com/products/photoshop.html
SOURCE LINK


Create Participant Layers
In each iPad for each participant (n), create two transparent layers:
  • Student n (a)
  • Student n (b)
Set Brush and Color Parameters
-Set brush size to 3 px.
-Apply colors based on the layer label:
  • All layers labeled “(a)” (e.g., Student 1 (a), Student 2 (a), …) → Green (RGB: 0, 255, 0)
  • All layers labeled “(b)” (e.g., Student 1 (b), Student 2 (b), …) → Yellow (RGB: 255, 255, 0)


photoshop workspace

Participant Recruitment and Grouping
Recruit at least 30 participants with a homogeneous background in paleontology and knowledge about footprints. (e.g., fourth-year geology students).
Pre-experiment demonstration
Show an example of the expected result on a separate footprint before the experiment

example of perimeter

example of detail

Divide participants into two groups:
  • RTI group
  • VRTI group
Experimental environment

The experiment should be conducted in a large room to allow the space to be divided into two distinct sections, each assigned to one of two groups. Each section will include two seating stations:
  • Station A: equipped with an Android tablet
  • Station B: equipped with an iPad and Apple Pencil.

The experiment will be conducted simultaneously for both groups. Participants will begin in turn at Station A and then proceed sequentially to Station B. The experiment should take place in a controlled session (e.g., during class) to ensure comparable training conditions.
Station A—Interactive Exploration Task
2m
each participant explores the RTI viewer on the tablet and adjust the light direction.

  • RTI group explore RTI footprint
  • VRTI group expore VRTI footprint

2m
The participant captures a screenshot of the lighting condition they consider optimal for morphological interpretation.



Station B – Annotation Task
4m
Each participant, in turn, is asked to identify and draw the footprint perimeter and a specific detail, in this case, the digit pad of the second finger in the Photoshop workspace.

  • RTI group draw on RTI footprint
  • VRTI group draw on VRTI footprint
Equipment
apple pencil
NAME
Apple
BRAND

Equipment
Ipad
NAME
Apple
BRAND
The specific model is not critical; what is essential is compatibility with the Apple Pencil.
SPECIFICATIONS

Instruct participants to:
  1. Trace the footprint perimeter on layer Student n (a) in green (RGB: 0, 255, 0)
  2. Mark the digit pad of the second finger on layer Student n (b) in yellow (RGB: 255, 255, 0)

Note
The thickness and the colour of the trait must be consistent at 3 px during the entire experiment.

Note
  • It's important to annotate only features they consider reliable.
  • The perimeter does not necessarily require closed contours.

4m
Export and Organization of Annotation Layers
Open the completed Adobe Photoshop file containing all participant annotations.

Expected result
For each participant, the assigned pair of layers:
  • Student n (a) Footprint perimeter
  • Student n (b) Digit pad annotation

Export each layer individually as a separate .png file, ensuring that:
  • Only the selected layer is visible during export
  • The original image resolution is preserved
  • The background remains transparent or neutral
Organize the exported files into two groups based on annotation type:
  • Group A (Perimeter annotations)
  • Group B (Digit pad annotations)
Within each group, structure the files using a consistent naming convention, for example:
  • Student n_(a).png
  • Student n_(b).png