Patent ID: 7706632

Claim:
A method of producing a multiple focus stack image of a target, the stack image comprising a plurality of images of at least a same area of the target, each image having a distinguished focus position or range of focus positions, the method comprising: causing, by a scanning device, relative scanning movement between the target and an array of light detectors, the array being used to repeatedly receive image information from the target during the scan in the form of scan lines; and causing, by a focusing device, a relative focus between the target and the array to be modified between said focus positions or ranges of focus positions of the respective images during the scan so as to obtain scan lines corresponding to each focus position or range of focus positions during the scan, thereby obtaining the images in the stack, wherein each image is formed from the image information obtained as scan lines at the respective focus position or range of focus positions during the scan; wherein the relative focus is cycled between two extreme focus positions or ranges of focus positions during the relative scanning movement and at least one scan line is obtained at a focus position or range of focus positions located between subsequent extreme focus positions or ranges of focus positions during the scan, each scan line being used to form one of the images of the target.