The area of an object is expressed in pixels and represents the total number of pixels that have been activated when detecting the particle as can be seen in the figure.
An area classification routine is used to determine which pixels belong to a specific particle. This algorithm works by scanning pixel by pixel from the top left to the bottom right corners of the image. During this scan, the software analyzes each pixel above and to the left of the current pixel to determine if the pixel belongs to an existing particle or whether it is a new particle.
The equivalent circular diameter of an object is expressed in microns and represents the diameter of a sphere that occupies the same two dimensional surface area as the particle. The MFI product platform converts the area of an object into an ECD value using proprietary conversion techniques to avoid the error inherent with performing direct calculations based on field of view dimensions. The conversion techniques are based on a mapping of the entire instrument size range using NIST traceable polystyrene beads. Although the conversion is based on polystyrene beads, the unique operation of the MFI product platform will guarantee the results obtained from the instrument are insensitive to the particle material properties. Therefore, the instrument does not require calibration against specific sample types for proper operation.
The intensity parameters of an object are expressed in illumination intensity levels. The number of levels available is directly related to the bit depth of the camera sensor used in the imaging sub-system. In the case of MFI, a 10 bit sensor is used which provides 1023 levels of intensity resolution. Due to the automatic and stable control of the illumination source, the intensity levels can be used as a relative metric for comparing particle absorption characteristics. Intensity Mean, Standard Deviation, Min and Max are provided.
