International audienceThis article presents a binary position encoding method for extended two-dimensional surfaces. Position encryption is based on linear feedback shift register sequences inserted within a periodic frame of spots. The position and orientation of any local view is retrieved accurately with respect to the encrypted surface. Image processing combines phase computations with binary image feature analysis. Measurement resolution is in the range of 10-2 pixel in position and 10-3 degree for in-plane orientation. The method is used as a visual sensor in a position control loop applied to fluorescence optical microscopy for the recovery of cells of interest within culture dishes