Dear Everybody,

I read recently a very fascinating story in G Wyszecki and W S Stiles book on Colour Science, which was attributed to Redhead, who had attributed it to H R Post: Once upon a time there was a farmer who often had to construct gates for his fields. Over the years he noticed, that to construct the gate he needed two pieces of wood of length x, for the horizontal beams of the gate, two pieces of wood of length y, for the vertical beams of the gate, and one piece of wood of length l to put across the diagonal. He was a clever farmer and he noticed that the larger x and y were, the larger l should be. However, he did not know Maths and he had never heard of Pythagoras. Over the years, he worked out that 1 should be a little shorter than x+ y and in fact he defined an (unknown) function f(x + y) to express their relationship. During the long winter nights when work in the farm was not possible, he amused himself by working out, using his experience, plots of f(x + y) versus x, plots of f(x + y) versus x + y and so on. All very complicated, but carefully done to help him and his descendants be able to work out from the graphs what size pieces of wood they would need in order to construct a gate of a certain size.

This story is fascinating because it echos a lot of what often goes on in Science: Ptolemy developed an elaborate theory on epicycles to explain the movement of the planets around the Sun, based on the premise that the Earth was at the centre of the planetary system. If he could only had paid attention to Aristarchus who 360 years earlier had argued that the Sun must be at the centre of the planets, things would have been so much easier! It took another 1400 years before Copernicus came along to re-discover Aristarchus theory and make redundant the elaborate epicycles of Ptolemy. The story repeated itself with Maxwell's equations and Lorentz transforms. It took Einstein to put the whole issue right, by making a simple conjecture: The mass of an object changes when it moves.

I was recently in a workshop in Belize and there I heard Rama Chellapa saying the unforgetable: "In Computer Vision, we do not solve the problems; we just get tired of them!" Is it because our Copernicus has not come along yet? Or is it even worse, our Aristarchus has not been born yet? How far do we have to go before something clicks and all falls into place? Perhaps the farmer's son will do Pythagoras at school, go home tell his father and all will be straightforward from there and on! And perhaps the farmer will find something else to fill up his long winter nights, hopefully another mathematical game!

Maria Petrou

PS: I come to think now, that as the editor of IAPR I really ought to say that the farmer himself should actually attend the 13th ICPR in Vienna where ALL issues of Pattern Recognition will finally be sorted out!