In a confocal imaging system, the image is built up point by point and is therefore well suited for image digitization and processing. A confocal system also allows range information to be obtained which facilitates an understanding of the 3D ·structure of the object. The results of several digital image processing techniques applied to images from a confocal scanning optical microscope aTe presented. In order that an image may be processed accurately and effectively, it is necessary to know the properties of image formation of the particular system, i.e. whether the system is coherent or incoherent, the transfer function of the imaging system, etc. In many applications such informa tion is unknown and it is therefore necessary to estimate the imaging properties. At other times the transfer func tion may be known but so complex that simplifYing approximations are applied, e.g. for optical microscopy incoherent imaging may be assumed even though for high resolution the imaging is necessarily partially coherent. In a confocal imaging system' , the object is illuminated by focussing a coherent source and the signal is received by a point detector, the back projected image of which is arranged to coincide with the illumination on the object as shown in Figure 1. Confocal imaging has several desirable properties for digital image processing. These include • purely coherent imaging • range information of the object may be obtained, i.e. the relative distance of its surface from the observer • improved resolution over a conventional imaging system using the same aperture and wavelength is attainable A confocal system, by its very nature, must scan the object in order to produce an image. Thus the image may be digitized very simply. This paper describes the results of applying simple digital processing algorithms to a confocal scanning optical microscope. In a confocal microscope the object is usually scanned relative to a finely focussed laser beam as shown in Figure 1 rather than vice versa' . Because the