Method and device for focussing in a camera, and camera comprising such a device

Abstract

Abstract 1. A method for adjusting the objective of a television camera in using the values of N=SIGMA g(i,j), (i,j)epsilon F where F is an analysis window contained in the analyzed picture, where (i,j) is a point of the analysis window situated on the line i and on the column j of the picture, and where g(i,j) is a gradient of the value X(i,j) of the television field video signal delivered by the camera, said method consisting in effectuating systematic unitary displacements of the lenses of the objective, in comparing for each position of these lenses the value N with the value N of the preceding position, and in searching for a maximum value of N, characterized in that the method consists in selecting the considered gradient among at least two of the four gradients X(i,j)-X(i,j-1), X(i,j)-X(i-1,j), X(i,j)-X(i-1, j-1), X(i,j)-X(i-1, j+1) and, when a maximum value of N has been found, with a first one of the gradients around a given position of the lenses, in examining whether or not said given position is the final one, by searching around the given position an other maximum value of N with at least one of the other gradients than the first gradient.

Inventors

• 👤 Alain Ferre
• 👤 Pierre Delsarte

Bibliographic Details