An objective lens of X40, a projective lens of X1.25, and a tube factor of X6.12 were used to obtain a final magnification of X306 on the video monitor. The position of the glass slide was fixed on the microscope stage, and each gray-scale image, consisting of 512 X 480 picture elements (pixels), was obtained for computer analysis by averaging 32 successive video frames from the video camera according to the manufacturer’s instructions. Illumination was set for optimal uniform brightness throughout the microscopic field of view and was unchanged throughout the analysis period. In addition, the background subtraction technique was used to account for any visually undetectable nonuniformity of light in different areas of the microscopic field. antibiotics levaquin
Moreover, the position of the measuring box was kept constant in relation to the microscopic field of view so that the same part of the field was measured for all images. Gray-scale values (mean and standard deviation) were measured on a scale ranging from 0 (pure black) to 255 (pure white) in a 140 X 140 pixel-area box representing 0.25 mm2 of the original section for the corpus luteum, and in a 34 X 167 pixel-area box representing 0.06 mm2 of the original area for the follicle wall (Fig. 2).