This application is very simple (but it does not yet work on mobile devices). When you participate, the platform will load a photograph of an archaeological artefact. Once the image has been loaded, you will be asked to click or tap around the edge of the artefact in order to define a polygon outline. Click once every time you wish to add a point along the edge of the polygon and your final point will snap back onto the one you started with. You can draw one polygon around the entire object or instead draw a series of overlapping polygons if you prefer. In general, we would like you to draw your polygon(s) very slightly inside the actual edge of the artefact. This is because we don't want background pixels near this edge to create a fuzzy border, and we don't need to worry so much about losing a bit of the artefact edge, as the missing few pixels are very likely to appear in one of the other photographs (at least 40 overlapping photographs are likely to exist for each object to support the construction of the 3D model). An example of a successful outline is shown below:
This specific photo-masking application includes very delicate gold ornaments. The bracelets presented here have minute details such as hooked fastenings, which may be challenging to mask. We recommend masking these details by drawing an outline around them, including some of the backround as well, as in the example below:While the resulting masks would be less accurate, it is better not to risk losing these types of small details.
How to use the applilcation's photo-masking toolbar:
Outline: This button is selected and enabled by default, indicating that your following actions, i.e. drawing and editing, will relate to the outline of the object.
Holes: This button is usually not available, but will be a part of the photo-masking toolbar whenever you are presented with an object that has 'holes', such as bracelets. In these cases, the background should be masked out and excluded from the object's final mask. Click on 'Holes' before starting to draw or edit a hole in the object.
Draw: This option is selected by default, at the beginning of a task. Click on 'Draw' whenever you want to start drawing an outline of the object. Once you complete an outline polygon, the delineating line will turn from blue to yellow.
Edit: This option is enabled once there is at least one complete polygon drawn. After clicking on 'Edit', choose the polygon you wish to edit by clicking once anywhere inside the polygon. It's line will turn blue, and become available for editing by re-positioning the blue nodes.
Remove all polygons: Use this option if you wish to start over. Clicking this button will remove all drawn polygons.
Save the drawings: Click on this button when you are done photo-masking the object - it will save and submit your mask.
Tip: You could draw a relatively rough polygon around the object to begin with, and then zoom in and click on the 'Edit' button. Then you could edit your polygon much more carefully, moving along the object's outline and fixing your initial polygon to create an accurate mask.
During the task, you can always return to this tutorial via the "Tutorial" button.
An example of a finished 3D model has now been completed.
To find out how the project is progressing, to suggest changes to this application or to propose new research ideas based what you have photo-masked, please have a look at our community forum.