Evaluations of Auto-Focusing Methods under a Microscopic Imaging Modality for Metaphase Chromosome Image Analysis

Abstract

Background: Auto-focusing is an important operation in high throughput imaging scanning. Although many auto-focusing methods have been developed and tested for a variety of imaging modalities, few investigations have been performed on the selection of an optimal auto-focusing method that is suitable for the pathological metaphase chromosome analysis under a high resolution scanning microscopic system.Objective: The purpose of this study is to investigate and identify an optimal auto-focusing method for the pathological metaphase chromosome analysis.Methods: In this study, five auto-focusing methods were applied and tested using metaphase chromosome images acquired from bone marrow and blood specimens. These methods were assessed by measuring a number of indices including execution time, accuracy, number of false maxima, and full width at half maximum (FWHM).Results: For the specific condition investigated in this study, the results showed that the Brenner gradient and threshold pixel counting methods were the optimal methods for acquiring high quality metaphase chromosome images from the bone marrow and blood specimens, respectively.Conclusions: Selecting an optimal auto-focusing method depends on the specific clinical tasks. This study also provides useful information for the design and implementation of the high throughput microscopic image scanning systems in the future digital pathology.

An algorithm selection methodology for automated focusing in optical microscopy

“…These criteria have an optimal value equal to zero because they are defined by mimicking the features of an ideal function, which has an unequivocal maximum (Osibote et al, 2010; Qiu et al, 2013). Figure 3 shows an example of each criteria, which are defined as follows. Accuracy : Number of images between the maximum of the contrast function and the focus position determined by an expert.…”

“…These criteria have an optimal value equal to zero because they are defined by mimicking the features of an ideal function, which has an unequivocal maximum (Osibote et al, 2010;Qiu et al, 2013). the clarity with which it shows the maximum value.…”

Comparativa de métodos de segmentación para el análisis automático de cromosomas humanos

“…Estos 23 pares se organizan en 22 pares, denominados autosomas y un par de cromosomas sexuales (X e Y) que diferencia ambos sexos (hombre XY y mujer XX). El análisis de las anomalías cromosómicas (ya sean de tipo numéricas y estructurales) se realiza a través del cariotipo, el cual es obtenido a partir de muestras de sangre periférica, muestras de médula ósea (Qiu et al, 2014) y en las embarazadas, del líquido amniótico (Qiu et al, 2013); a estas muestras se le aplica una tinción con un colorante fluorescente y se cultivan para estimular la división celular, después de un tiempo óptimo en cultivo, las células se encuentran en metafase y mediante el microscopio es posible visualizar y obtener imágenes de los cromosomas, ver Figura 1.…”

Surface determination of 3D confocal Raman microscopy imaging of the skin

“…Also, different image analysis methods of a microscopic overview image can be used for auto focusing [30,31]. In this case, the surface can be determined at the position with the highest contrast of recorded sample structures and the out-offocus images are detected by a lower amount of high frequency content in the image data.…”