Browsing by Author "Machikhin A."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Dynamic speckle imaging with SVD compression
    (2022-01-01) Stoykova E.; Levchenko M.; Ivanov B.; Madjarova V.; Nazarova D.; Nedelchev L.; Machikhin A.; Park J.
    Dynamic speckle imaging (DSI) of areas with different speed of processes ongoing in industrial or biological objects relies on statistical processing of a large number of images of the speckle patterns formed on the objects surface under laser illumination. The DSI visualizes the speed spatial distribution as an activity map. We propose compression of the raw DSI data by applying singular value decomposition (SVD). A specific feature of speckle images for DSI is lack of a structure with areas of close intensity values. The gain from the direct SVD application may be modest in cases when a great number of non-zero singular values is needed to build an activity map comparable in quality to the ground truth map from bitmap images. For higher compression, we propose SVD to be applied to the 2D arrays containing the differences between the successive images. The SVD compression has been verified by using synthetic and experimental data.
  • No Thumbnail Available
    Item
    Visualization of pathologic changes in liver tissue via polarized light
    (2022-01-01) Stoilova A.; Blagoeva B.; Nazarova D.; Stoykova E.; Berberova-Buhova N.; Nedelchev L.; Machikhin A.
    In this work, we applied two polarized light based approaches to visualize histological patterns of liver pathologies. The first one involves acquisition of two images through a polarizing microscope, one image (Ppar) acquired with the analyzer oriented parallel to the polarization of illumination and the other (Pper) acquired with the analyzer oriented perpendicular to the illumination. The final image is based on the polarization ratio, Preconstructed = (Ppar - Pper)/(Ppar + Pper). Using the second technique, the histological specimens were illuminated with a polarized laser beam with wavelength of 635 nm. Polarimetric parameters as azimuth, angle of ellipticity, degree of polarization and reflected power have been measured to quantify the change in the polarization state of the incident light after interaction with the sample of the healthy tissue and of the tissue with abnormal morphological changes.