Patent ID: 6704054
Filing Date: 2004-03-09
Classification: G06K,H04N

Abstract:
An autofocusing system for focusing an image of a subject in an electronic image pickup apparatus, said autofocusing system comprising:an imaging optical system which receives said image of said subject, said imaging optical system including a focus lens group; an image pickup device which performs a photoelectric conversion of said image of said subject to produce an electronic image signal; a driving circuit which controls said focus lens group to move through one of a first range and a second range of positions, said first range being larger than said second range; an auto-focus processing circuit which detects a high-frequency component of said electronic image signal and detects additional high-frequency components of additional electronic image signals produced due to movement of said focus lens group caused by said driving circuit; said driving circuit controls said focus lens group based on an output of said auto-focus processing circuit; a light source which radiates infrared light toward said subject; a light receiver which receives reflected light produced by reflection of said infrared light on said subject, said light receiver producing an output signal corresponding to a distance between said electronic image pickup apparatus and said subject; a controller which controls said driving circuit to move said focus lens group through said first range of positions when said distance to said subject is shorter than a predetermined distance and controls said driving circuit to move said focus lens group through said second range of positions when said distance to said subject is greater than said predetermined distance.