Subsections

• Pollen grain detection and localisation
• Pollen grain extraction
• Man-machine interface

Pollen grain extraction

This module is developped at LASMEA.

Pollen grain detection and localisation

An automatic pollen grain extraction is done following these steps:

• Automated image focusing on pollen grains: In microscopy, the conception of a process for automated analysis of samples implies that the reading device is able to rectify image sharpness in real time. Here, it is demonstrated that the association of the relative sharpness criterion SML (Sum Modified Laplacian) and a maximum search strategy ensuing from Fibonaci's paradigm, leads onto a fast and robust algorithm for automated sharpness rectification.
• Localisation of pollen grains from colour information: In order to sort particles on the samples and localise the pollen grains, an algorithm based on a split and merge scheme with markovian relaxation, has been developed for joint segmentation of a luminance plane and a chrominance plane, coming from the principal components analysis of specific RGB data of the application. Automated interpretation of the segmentation results completes the colour analysis module and also enables an efficient localisation of the grains (more than 90 the strong variations of coloration among the different pollen types). The repetitive aspects of the sample slide analysis is totally automated.
• Digitization of pollen grains in three dimensions: The pollen grain is automatically digitize from its central section into a sequence of 100 images with a step of 0.5 microns between sections.

Pollen grain extraction

We perform a 3D acquisition of the pollen grains, resulting in a set of images at different depths (focus).

For each pollen grains:

• 100 optical sections are digitized
• the step between images is 0.5 microns

Man-machine interface

The system can work in supervised or in automatic mode. An interface allows the user to manipulate the system in supervised mode and to see the content of the microscopic slide.