A tremendous technological progress in both digital image acquisition and processing has occurred in recent years with the development of new tools for automatic plankton detection and recognition. Nevertheless, considerable challenges persist because body sizes and morphologies are extremely variable within plankton communities. It is virtually impossible to acquire plankton images covering a wide size range with a single optical system, due to inherent physical constraints.
Nowadays the techniques based on the 2D imaging for characterizing size and shapes of organisms are fast, but suffer from limited depth of focus imposed by the required magnification. Consequently, captured images contain blurred and out of focus objects limiting the successful application of image analysis. Digital in-line lens less holography is a promising tool for monitoring sample in liquid environment.
From the hardware point of view, the compactness of the setup and the deep of focus free represent the major advantages in comparison with all the microscopy techniques. Many cameras with different recording speed, pixel resolution and size of the detector available on the market can satisfy the customer application requirements. All these features converge in the direction of a compact on board instrument and on site preliminary analysis. In this context, a key point is the software for the 3D reconstruction.
Miming a commercial digital camera, we firstly engineered our optical setup. In parallel, we developed a novel ergonomic interface to provide scientist not fully experienced in the field of holography with a user-friendly observation tool for oceanographic applications. We present here our preliminary promising results in terms of resolution (focal distance) and processing speed.
