초록 ▼

In an automatic focusing apparatus which detects sharpness signals from high-frequency components of brightness signals contained in video signals from video cameras and which stops a focusing lens of the video camera at a position at which its peak value is obtained, the movement of the focusing le

In an automatic focusing apparatus which detects sharpness signals from high-frequency components of brightness signals contained in video signals from video cameras and which stops a focusing lens of the video camera at a position at which its peak value is obtained, the movement of the focusing lens is started by detecting received light signal levels by performing projection-reception operations with a specified amount of infrared light and detecting their variations with a received light signal level detector or with a micro-computer. Furthermore, depending upon the focal depth of the focusing lens, priority is given to processing of distance information based on sharpness signals or distance information determined by the infrared light projection-reception operation in the lens driving controller for performing the focusing operation. According to the automatic focusing apparatus of the present invention, movement of the lens only due to variations of contrasts can be avoided, and stable image pictures are thus obtainable. Also, the most suitable focusing operation mode for a particular focal depth of a lens in use can be selected.

대표청구항 ▼

An automatic focusing apparatus with a lens movement termination means, comprising: a sharpness signal generation means which detects a sharpness signal from high-frequency components of a brightness signal contained in a video signal corresponding to an object; a maximum value detection means which

An automatic focusing apparatus with a lens movement termination means, comprising: a sharpness signal generation means which detects a sharpness signal from high-frequency components of a brightness signal contained in a video signal corresponding to an object; a maximum value detection means which generates a lens movement termination signal which stops movement of a focusing lens when said sharpness signal has a peak value; a distance variation detection means comprising a light projection means which projects a specified amount of infrared light onto said object, a light reception means which receives reflected lights caused by projection of said specified amount of infrared light onto said object, and a received light signal level variation detection means which detects variations of the light level of said reflected infrared light for issuing a lens movement start signal; and a lens driving means including a driving source for controlling the movement of a lens in response to said lens movement termination signal and said lens movement start signal.