The size-of-source effect in thermography

In thermometry, the displayed temperature value of an object depends on the size of the object. This behaviour, also known as the size-of-source effect (SSE), might be a major cause of measurement uncertainty in a thermoscene. The SSE is caused by diffraction, scattering, reflection, aberration and digitization in the optoelectronic propagation path. The influence of diffraction and digitization (sampling and pixelization) can be described advantageously with the modulation transfer function MTF. The system MTF of an uncooled camera is determined by the diffraction in the lens (optical MTF) and the averaging of the radiation over the pixel area (pixel MTF). If the system MTF is known, the contrast reduction and, thus, the SSE can be calculated. Especially with very small objects, e.g. hotspots creating an image covering less than 4 pixel × 4 pixel on the focal plane, the displayed temperatures are much too low. When imaging large objects, such as area blackbodies, not only the edge areas are affected, but also the entire image. Finally, the contrast reduction by the MTF is explained by means of a complex scene (Siemens star).

Summary Tables

The three tables that follow provide an easily accessible comparative summary of the key points and features of the major characterization methods discussed in the text. The techniques are classified into three broad groups/methods: spectroscopy/chemical, diffraction/scattering, and imaging. For each technique, a concise description of the method and its use is followed, in bullet form, by its salient details and other characteristics, such as resolution, sensitivity etc., as well as specimen requirements that determine its practice. A general estimate of cost and space requirements is also included, but needless to say, this is only a snapshot for comparison and is definitely subject to change with time.

DIFFRACTION EXPERIMENTS WITH KOSSEL PHOTONS

In the paper an attempt was made to obtain some information about the characteristics of photons as separate objects with the properties of localization in ordinary coordinate space. Experiments of various complexity with Kossel photons were carried out on a multiaxial diffractometer. A diffraction spectrometer with perfect calcite crystals was used to register the photons. The bidirectional angular measurements were carried out with sufficient angular and energy resolution to detect the influence of the coherent volume of the photons on the measurement results. The measurements showed some correlations that had not been paid enough attention before. Those effects were measured separately for Kα1 and Kα2 photons to allow their comparison. Such approach corresponds to the modern quantum mechanics of the photon; that mechanics showed the possibility of existence of wave functions of photons in their usual standard sense. Data on spatial parameters Kα1 and Kα2 of Kossel photons were obtained by comparing the effects of their diffraction scattering

MODEL BIOMEMBRANES AS TEST OBJECTS FOR THE DETERMINATION OF CONCENTRATION RANGES OF HARMFUL CHEMICAL SUBSTANCES IN BIOLOGICAL MEDIUMS AND OBJECTS OF EXTERNAL ENVIRONMENT

The paper presents data on changes in model biomembranes (liposomes, erythrocyte shadows, erythrocytes) used as test objects to determine those ranges of concentrations of biologically active substances in which there is no violation of the structure or function of experimental objects. Melaphene, plant growth regulator used in small doses in seed pre-treatment, and antioxidant phenosan derivatives, phenoxane and IHFANs, have been used as biologically active substances. It was shown by DSC that phenosan derivatives at concentrations equal to 10-5 M and higher destroy the microdomain organization in the bilayers of phospholipid multilamellar liposomes and reshape protein microdomains in the shadows of red blood cells. Melaphene in small and large concentrations changes polymodal the microdomain organization in the bilayers of phospholipid multilamellar liposomes without destroying the structure and does not affect the protein microdomains in the shadows. An increase in the membrane permeability in isolated intact erythrocytes in the presence of melaphene in large and small concentrations has been revealed by means of spectral anaslysis. The method of small-angle diffraction scattering showed the absence of the effect of melaphene in a wide range of concentrations on the thickness of phospholipid bilayers and the order of their packaging in multilamellar liposomes.