Segmentation & generation of thickness maps of contact lenses
Project Description

The project was made for AM2M sp. z o.o. from Torun - spin-off company which works as a liaison between Nicolaus Copernicus University and companies interested in using science in their business.

One of the projects implemented by AM2M sp. z o.o. was to build an optical device which can measure parameters of contact lenses produced by a collaborated company.
After assembling an optical setup and acquiring the data by another part of the group, my job was to create a segmentation algorithm and to analyse such an object with it.

The whole project was done in Silverlight (image). Design of application was based on the application for retina segmentation.
Segmentation results can be view as a 2D image and as a 3D model (1st), a 3D model (2nd).

After completing the segmentation algorithm I created algorithms for calculation of thickness maps of a contact lens.
The first step which was required was a creation of a 2D ray tracing algorithm. Ray tracing is required because the light that passes from a medium of a given refractive index to the medium of different index of refraction bends at a different angle in this medium than it has in the first one (except for the perpendicular illumination). As a result of it, we observe the different shape of an object in the 2nd medium than it really is. In case of contact lenses in my work, a shape of the contact lens was changed because of ultra lipid.
The image shows ray tracing results in comparison to the previously showed image.
Next step was the creation of an algorithm for calculating the thickness maps of a contact lens. Such calculation can be done in two ways, either vertically to contact lens position or in normal vector surface of contact lens direction.
Both ways were implemented. The first image presents vertical and second normal vector direction.

Our work was presented at SPIE Photonics West which took place on 1-6.01.2014 in San Francisco, California (USA). The title of the presentation was "Swept Source Optical Coherence Tomography for soft contact lens measurements".

Project Details