Analysis of influence of cell nuclei segmentation in Papanicolaou smears on fractal dimension measurements

W artykule badano wrażliwość metody pryzm trójkątnych (TPM - Triangular Prism Method) do estymacji wymiaru fraktalnego dla różnych rozmiarów jądra komórkowego w cytologii ginekologicznej wybarwionej metodą Papanicolaou. Zmiana obszaru analizy pozwala na zmniejszenie wpływu algorytmu segmentacji na wynik. Wykorzystanie kanału zielonego gęstości optycznej i zmian wymiaru fraktalnego dla par skal: 1-2 oraz 2-3 pozwala na otrzymanie wyników dla systemu klasyfikacji z małą wrażliwością na segmentację.In the paper the influence of segmentation algorithms on estimation for the fractal dimension is analyzed. The Papanicolaou smears are very complex images and their automatic analysis is very hard. Segmentation algorithms of cell nuclei should support blurred and noised edges between cytoplasm and cell nucleus. The estimation of the cell nuclei image parameters is necessary, but the edge related parameters are not sufficient. The classification of the cells (correct/atypical) needs surface related parameters. Fractal based estimators are important for classification. The Papanicolaou images are colourful but only the green channel is important [9]. The TPM (Triangular Prism Method) is applied to the square area (2N+1 edge size) [5]. Multiple box selection variants occur and the multiple TPM analysis is applied and the mean value is calculated. The fractal dimension is calculated for a pair of scales (1-2, 2-3, 3-4). The correct and atypical cell nuclei are known and the analysis is separated. The histograms of difference between the known and reduced cell area are shown (Figs. 6-11). The atypical cells are less sensitive due to a larger size of the analysis area in comparison to the correct ones. Two scales (1-2) and (2-3) are useful, especially for smaller reduction parameter (erosion up to 9 pixels of original cell nuclei). Both scales are used in the classification system [9]. The fractal dimension changes are less than +/- 1%

From the slit-island method to the Ising model: Analysis of irregular grayscale objects

The Slit Island Method (SIM) is a technique for the estimation of the fractal dimension of an object by determining the area– perimeter relations for successive slits. The SIM could be applied for image analysis of irregular grayscale objects and their classification using the fractal dimension. It is known that this technique is not functional in some cases. It is emphasized in this paper that for specific objects a negative or an infinite fractal dimension could be obtained. The transformation of the input image data from unipolar to bipolar gives a possibility of reformulated image analysis using the Ising model context. The polynomial approximation of the obtained area-perimeter curve allows object classification. The proposed technique is applied to the images of cervical cell nuclei (Papanicolaou smears) for the preclassification of the correct and atypical cells

Adaptive method of contrast enhancement for digital images of cytological smears

Wstęp i cel: Zwiększenie kontrastu między jądrem komórkowym a cytoplazmą zapewnia poprawę wizualizacji cytologicznych cech komórki. Celem pracy jest poprawa wizualizacji jądra komórkowego. Materiał i metody: Automatyzacja doboru progu z wykorzystaniem algorytmu adaptacyjnego progowania dla rozkładów dwumodalnych została przeprowadzona dla obrazów rozmazów cytologicznych. Wyniki: Uzyskano zwiększony kontrast dla jądra komórkowego, dzięki czemu osiągnięto poprawę wizualizacji struktury chromatyny. Wniosek: Adaptacyjna metoda poprawy kontrastu może być użyteczna w diagnostyce cytologicznej, ale potrzebna jest weryfikacja w oparciu o większą bazę danych obrazów cytologicznych.Introduction and aim: Contrast enhancement between nucleus and cytoplasm ensures improvement of cytological features visualisation. The aim of study is improvement of nucleus visualisation. Material and methods: Automation of threshold estimation with the use of adaptive tresholding algorithm for bimodal distributions was provided for images of cytological smears. Results: Improved contrast for cell nuclei was obtained and therefore the enhancement of chromatine structure visualisation is achieved. Conclusion: Adaptive method of contrast enhancement could be useful in cytological diagnosis, but requires verification with the use of large database of cytological images