Multi-channel imagesFluorescence microscopes can usually register different emission wavelengths (almost) simultaneously, allowing you to image different dyes on the sample. In the terminology of the Huygens Software, one channel in a 3D image refers to the intensity distribution recorded at a given fixed wavelength, independently of what device made the acquisition. Thus, it is a logical channel of stored data, and not necessarily a physical channel (as all the image channels could have been measured by a single photomultiplier, for instance).
In the Huygens Software, every channel is therefore deconvolved independently, using specific microscopic parameters (in an ideal cross talk free situation there's no correlation between channels). A multi-channel image requires a multi-channel point spread function.