ABSTRACT
Many imaging applications deal with the detection of small targets or spots embedded within an inhomogeneous background. We present a method that accomplishes a multiresolution detection on the wavelet-transformed image. The targets are separated from the background by the exploitation of Renyi's information, which is evaluated at the different decomposition levels of the wavelet transform. The scale-dependent candidate detections are successively combined by means of majority voting for final detection. Connections with results provided in different fields such as multifractal analysis, generalized information measures in scale-space, and cross-entropy analysis in fine-to-coarse transformations are discussed. Detection performance is investigated through an example from medical image analysis.
Subject(s)
Diagnostic Imaging , Entropy , Differential Threshold , Female , Humans , Mammography , Models, TheoreticalABSTRACT
Microcalcification detection is widely used for early diagnosis of breast cancer. Nevertheless, mammogram visual analysis is a complex task for expert radiologists. In this paper, we present a new method for computer aided detection of microcalcifications in digital mammograms. The detection is performed on the wavelet transformed image. The calcifications are separated from the background by exploiting the evaluation of Renyi's information at the different decomposition levels of the wavelet transform. Experiments are performed on a standard and publicly available dataset and the results are evaluated with respect to recent achievements reported in the literature.
Subject(s)
Breast Neoplasms/diagnostic imaging , Calcinosis/diagnostic imaging , Diagnosis, Computer-Assisted/methods , Mammography/methods , Radiographic Image Enhancement/methods , Algorithms , Biometry , Female , Humans , Image Processing, Computer-Assisted/methods , Mammography/statistics & numerical dataABSTRACT
Changes in lymphocyte subsets in whole blood of normal pregnant women were examined by flow cytometry. From the first trimester and throughout pregnancy, the count of B cell subset remain unchanged. On the contrary, the percentage of "helper" lymphocytes decreased in the first trimester, increase in the third. These changes of lymphocyte subsets may indicate suppression of immunological activity during pregnancy.
