Abstract: A method for determining capacitance includes alternately charging a capacitor to a first voltage and discharging the capacitor to a second voltage, generating an output signal having a frequency that is a function of a time period, and determining the capacitance based on the frequency of the output signal. The time period is selected from at least one of: (a) a time period needed to charge the capacitor from the second voltage to the first voltage and (b) a time period needed to discharge the capacitor from the first voltage to the second voltage.

Abstract: An image analysis apparatus comprises a microscope (102) arranged to capture an image of a sample (122), a processor unit (114) arranged to process the image and a drive mechanism (108). The drive mechanism (108) is arranged to effect relative motion between the sample (122) and the microscope (102) typically along an optical axis of the microscope (102). The microscope (102) is arranged to capture a plurality of images (402a-404c) of the sample (122) at a plurality of points, typically, along the optical axis. Relative motion of between the sample (122) and the microscope (102) typically, along the optical axis is effected by the drive mechanism (108) and the processor unit (114) is arranged to divide each of the plurality of captured images (402a-404c) into a plurality of sub-images and select one of each of the plurality of sub-images having the best focus characteristics.