The invention relates to an observation apparatus (1) and method for visually enhancing the observation of an object (2). The observation apparatus (1) comprises an output color image projector (8) for projecting a time sequence (31) of output color images (32) onto a projection area (40) on the object (2). The output color image projector has an output spectrum (60) consisting, at least in the visible-light range, of a set of output spectral bands (60). The observation apparatus (1) further comprises a multispectral camera system (4) for capturing a time sequence (21) of input color images (22) from the projection area (40) in at least two input spectral bands (42). The input spectral bands (42) differ from the output spectral bands (62). The observation apparatus (1) is further configured to derive the output color images (32) from the input color images (22) and to project the output color images (32) onto the projection area (40) in real time. In that the input spectral bands differ from the output spectral bands, the output color images (32) can be processed by the observation apparatus (1) to deviate arbitrarily from the input color images (22) without impacting the operation of the camera system (4). This allows for example to replace any fluorescence input spectral bands by pseudo-colors and to modify colors, add symbols and letters and to change contrasts and brightness in the output color images (32) although they are projected directly onto the object on the same projection area which is captured by the camera system (4).
