Patent ID: 11882364
Assignee: HANWHA VISION CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. A focusing apparatus comprising:
a determiner configured to determine whether a region of interest set in a surveillance area is included in a first image obtained in the surveillance area by a camera performing a pan-tilt-zoom (PTZ) operation;
a mode selector configured to convert a mode according to a result of the determination by selecting a first mode in which focusing is performed using a first focusing algorithm or a second mode in which focusing is performed using a second focusing algorithm that is different from the first focusing algorithm; and
a focusing unit configured to focus the camera with respect to the first image according to the first mode or the second mode,
wherein the first focusing algorithm comprises an algorithm in which focusing is performed by automatically setting a focus area and moving a focus lens step-by-step such that the focus area is focused,
wherein the second focusing algorithm comprises an algorithm in which focusing is performed by setting the region of interest as the focus area and moving the focus lens to a preset position of the focus lens for the region of interest,
wherein the determiner calculates the ratio of a portion in the first image, the portion corresponding to a second image which is a previously stored image of the region of interest, and the mode selector converts the mode by selecting the first mode or the second mode according to the ratio,
wherein the determiner determines whether a pan value and a tilt value of the camera corresponding to the first image are in a preset range of pan values and a preset range of tilt values including a reference pan value and a reference tilt value of the camera corresponding to a second image, which is a previously stored image of the region of interest, and the mode selector converts the mode from the first mode to the second mode when the pan value and the tilt value of the camera are in the range of pan values and the range of tilt values, and
wherein, in the second mode, the focusing unit calculates a position of a focus lens set at a zoom magnification of the camera before the conversion of the mode, based on a relationship between a zoom magnification predefined with respect to the region of interest and a position of the focus lens, and moves the focus lens to the calculated position of the focus lens.