[Cognitive processes in perception: perceptive knowledge]

In an information processing approach, this paper attempt to show how different levels of processing visual information can be organized Sensory processing makes local coding of some dimensions. Then comme a step of structuration consisting in "putting together" these locally coded dimensions. These informations have finally to be interpreted on the basis of cognitive representations. Several examples are presented illustrating how ambiguities can appear between sensory information and various cognitive interpretations.