Detecting microscopic objects in fluids by optical sensing

A method for detecting microscopic objects of foreign origin present in a fluid, the method comprising:

• receiving a hologram digital image frame captured by an image sensor receiving light propagated across a sample volume, containing a fluid possibly comprising microscopic objects of foreign origin, while illuminating the sample volume by coherent light to create prepared image data, whereby the possible microscopic objects scatter part of the light, the scattered and non-scattered light interfering so as to form interference fringes behind the microscopic objects, resulting in a hologram pattern with spatially alternating intensity formed by the interference fringes;
• generating filtered image data, comprising automatically filtering the prepared image data as such without further processing, the filtering being performed by an edge enhancing filter to create the filtered image data, the filtered image data comprising a filtered holograph pattern resulting from the filtering of the hologram pattern;
• and
• automatically detecting, on the basis of the filtered hologram pattern, the presence of the microscopic object associated with the filtered hologram pattern in the sample volume of the fluid.