... productivity.REFERENCES 1. EL Hall. Computer Image Processing and Recognition.Academic Press, Orlando, FL, 19 79.2. CF Hall, EL Hall. A nonlinear model for the spatialcharacteristics of the human visual system. ... Wiley, NY, 19 92, pp 204±263. 11 . WS McCulloch and WH Pitts, ``A Logical Calculus of the Ideas Imminent in Nervous Behavior,'' Bulletin of Mathematical Biophysics, Vol. 5, 19 43, pp. 11 5 13 3. 12 . ... accidental. In particular, the focus and F-stop characteristic of cameras should usuallybe dif®cult to adjust once installed. A corollary of this is clearly that it should not need manualadjustment.6....