The PlanktoScope is an affordable, compact, digital microscope made of different simple modules.

The computing module is made of the latest Raspberry Pi 4 (4GB of LPDDR4 SDRAM) coupled with its Pi Camera (v2.1 - 8 megapixels). The optic is simplified using two reversed M12 lenses, the tube lens is fixed when the objective lens can be swapped offering a variety of optical configuration. A motorized stage (~30 µm/step) allows a fine focus calibration of the swappable stage on which it’s possible to mount either µ-Slide I Luer or traditional glass slide depending on the mode (fluidic or static observation). A peristaltic pump driven by a stepper motor owning an order of precision ~ 0.1ml/min is used to drag the fluid into the flow-cell if needed.

Workflow used to segment the objects imaged in a frame and to extract features. Several operations are applied on the raw images acquired in fluidic mode. MorphoCut first applies a running median to approximate the background image based on 5 frames, a Canny Edge Detection via OpenCV is performed, followed by a dilation, closing and erosion functions also from OpenCV. From the binary image, MorphoCut extracts the vignette/ROI for each present object.