Spectral bandwidth in automated leukocyte classification

Abstract

Investigators have repeatedly pointed out the importance of spectral information in the automated classification of white blood cells. In general, monochromatic images recorded through two or three color filters are used to extract this information. Although it has generally been thought that the use of narrow band filters provides "cleaner" color information than is obtainable through wide band filters, the choice has not been fully investigated and the question is far from being settled. The use of wide band filters has the clear practical advantage of increased light levels at the detector, resulting in higher signal-tonoise ratio with less demand on light source design.In order to investigate this issue, a series of 681 leukocytes of the most frequently occurring types were digitized by the use of both narrow (10 nm) and wide (90 nm) band filters. Parameters were extracted independently from both sets of images. These parameters were then used to develop a classifier for each set of images. The choice of features and classifier results indicate that there are no major performance differences between the two types of filters.

Dynamic Impedance Spectroscopy of Nickel Hexacyanoferrate Thin Films

“…By using quadrature filters, it is possible to simultaneously evaluate the dynamic impedance in a broad range of frequencies as a function of the time domain. In contrast to that, in classic electrochemical impedance spectroscopy (EIS), different frequencies perturb the system successively, rendering this tool unsuited for time evolving electrochemical systems.…”

Accurate label-free 3-part leukocyte recognition with single cell lens-free imaging flow cytometry

“…Several studies demonstrated new imaging technologies that provide both spatial and spectral information to support cell identification and can also potentially be integrated into on-chip blood analysis systems. Examples include hyperspectral imaging [ [5] , [6] , [7] , [8] , [9] ], multispectral imaging [ 10 ] or Raman spectroscopic imaging [ 11 ]. However, these studies were limited to the examination of blood smear samples, the preparation of which has been shown to yield different cell morphologies when compared to cells in suspension [ 12 ].…”