Specimen mounting and orientation

The mounting is adjusted to the center of rotation of a two-axis motorized gimbal and allows a free view on the specimen from virtually all sides. During an insect scan, the specimen undergoes a preassigned ‘pose program’ with an approximately constant angular distance between neighboring poses.

Illumination

Many insect surfaces are glossy and show bright reflections (‘hotspots’) when illuminated directly by a point-shaped light source as an LED. For that reason, we use a hemispherical illumination dome with a dimmable white LED stripe attached to its inner circumference.

Optics and Focus Stacking

A video stream of images is captured under front light as the macro rail moves the camera forward. After that, another video stream is taken under back-light resulting in back-light image used for masking. The image sequences are used for EDOF-calculations.

Image Acquisition and Processing

The complete process of image acquisition and processing is controlled by a PC under MATLAB. Camera configuration and start, as well as the readout of the images are accomplished via the USB3 Vision interface standard.

3D modelling

After the end of the scan, the masked EDOF images of all poses are transferred to the SfM software Agisoft PhotoScan Pro to generate 3D surface models.