IMAGE DEVICE, SURVEILLANCE CAMERA, AND MASK METHOD OF CAMERA SCREEN

• US 20130070092A1
• Filed: 08/10/2012
• Published: 03/21/2013
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: Hitachi Industry & Control Solutions, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: MIYAHARA, Hiroyuki, Shiozawa, Akinori, Asuka, Makoto
• Granted Patent: US 8,721,197 B2
• Time in Patent Office: Days
• US Class Current: 348/143
• CPC Class Codes: G08B 13/19686 Interfaces masking personal details for privacy, e.g. blurring faces, vehicle license plates
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/661 Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/695 Control of camera direction for changing a field of view, e.g. pan, tilt or based on tracking of objects

Abstract

In a microcomputer included in an image device, a mask 2D 3D converting section expresses coordinates of a 2-dimensional image plane defined by an imaging element having a rectangular contour in a 3-dimensional coordinate system. The image plane is positioned in the state that a focal length corresponding to a zoom position is adopted as a Z coordinate value of the image plane in the 3-dimensional coordinate system. A mask display position calculating section 165 calculates a 2-dimensional position of a mask on a camera screen by utilizing a similarity of the size of the image plane and the size of the camera screen when a position of a mask on the image plane in the 3-dimensional coordinate system after PAN, TILT rotations and a zooming is converted into the 2-dimensional position of the mask on the camera screen.

Claims

1. An image device including an imaging element which image device is mountable to a rotative table and for masking a partial area of a picture to be displayed on a camera screen so as not to be seen which picture has been captured by the imaging element, comprising:

a control position information obtaining section configured to obtain PAN and TILT rotation angles of said rotative table and a zoom position;

a mask generating section configured to calculate coordinates of corners of a first mask area disposed on an image plane defined by said imaging element, the coordinates being in a 3-dimensional coordinate system having an origin through which a central axis of a rotation for the PAN rotation angle and another central axis of a rotation for the TILT rotation angle pass;

a mask display position calculating section configured to calculate coordinates of corners of a second mask area on said camera screen in a 2-dimensional coordinate system from said coordinates of the corners of said first mask area calculated by said mask generating section by using a relation that distances between a plurality of corners of said camera screen and each corner of said second mask area are proportional to distances between a plurality of corners of said image plane and each corner of said first mask area with a constant ratio, respectively; and

a mask signal output section configured to be able to add a masking signal to a signal of the picture to be displayed on said camera screen so that the picture in said second mask area is not able to be seen.

2. An image device as claimed in claim 1, wherein said mask generating section comprises:

a mask 2D 3D converting section configured to calculate a first information of coordinates of the corners of said first mask area on said image plane positioned in the state that one coordinate axis of three coordinate axes in said 3-dimensional coordinate system passes through a center of and perpendicular to said image plane and when said zoom position is a preset position said image plane is positioned at a position with a coordinate value on said one coordinate axis which coordinate value is corresponding to said preset position;

a mask rotation processing section configured to calculate and store a second information to a memory section which second information is coordinates of the corners of said first mask area which coordinates are calculated by converting said first information into said second information for rotations based on PAN and TILT rotation angles of said imaging element as a result of a PAN rotation and a TILT rotation; and

a mask projected position calculating section configured to calculate coordinates of the corners of said first mask area which coordinates are those of intersections at each of which intersections each straight line connecting said origin and each corner of said first mask area with said second information derived from said memory section, and said image plane at a present time after a zooming and PAN and TILT rotations, intersect.

3. An image device as claimed in claim 1, further comprising a mask coordinate modifying section configured to convert said second mask area into a rectangular area having two sides each of which is parallel with each coordinate axis in said 2-dimensional coordinate system of said camera screen and circumscribes a contour of said second mask area in case that said contour is not a rectangle having a side parallel with a coordinate axis in said 2-dimensional coordinate system.

4. A surveillance camera having a camera including an optical lens unit, an imaging element and an image processing section for processing a signal of a picture captured by said imaging element and outputting a processed signal of the picture to a camera screen, and a rotative table supporting the camera rotatively, comprising:

a control position information obtaining section configured to obtain PAN and TILT rotation angles of said rotative table and a zoom position;

a mask generating section configured to calculate coordinates of corners of a first mask area disposed on an image plane defined by said imaging element, the coordinates being in a 3-dimensional coordinate system having an origin through which a central axis of a rotation for the PAN rotation angle and another central axis of a rotation for the TILT rotation angle pass;

a mask display position calculating section configured to calculate coordinates of corners of a second mask area on said camera screen in a 2-dimensional coordinate system from said coordinates of the corners of said first mask area calculated by said mask generating section by using a relation that distances between a plurality of corners of said camera screen and each corner of said second mask area are proportional to distances between a plurality of corners of said image plane and each corner of said first mask area with a constant ratio, respectively; and

a mask signal output section configured to be able to add a masking signal to a signal of the picture to be displayed on said camera screen so that the picture in said second mask area is not able to be seen,

whereby masking can be carried out in a partial area of the picture to be displayed on said camera screen.

5. A surveillance camera as claimed in claim 4, wherein said mask generating section comprises:

a mask 2D 3D converting section configured to calculate a first information of coordinates of the corners of said first mask area on said image plane positioned in the state that one coordinate axis of three coordinate axes in said 3-dimensional coordinate system passes through a center of and perpendicular to said image plane and when said zoom position is a preset position said image

plane is positioned at a position with a coordinate value on said one coordinate axis which coordinate value is corresponding to said preset position;

a mask rotation processing section configured to calculate and store a second information in a memory section which second information is coordinates of the corners of said first mask area which coordinates are calculated by converting said first information into said second information for rotations based on PAN and TILT rotation angles of said imaging element as a result of a PAN rotation and a TILT rotation; and

a mask projected position calculating section configured to calculate coordinates of the corners of said first mask area which coordinates are those of intersections at each of which intersections each straight line connecting said origin and each corner of said first mask area with said second information derived from said memory section, and said image plane at a present time after a zooming and PAN and TILT rotations, intersect.

6. A surveillance camera as claimed in claim 4, further comprising a mask coordinate modifying section configured to convert said second mask area into a rectangular area having two sides each of which is parallel with each coordinate axis of said 2-dimensional coordinate system of said camera screen and circumscribes a contour of said second mask area in case that said contour is not a rectangle having a side parallel with a coordinate axis of said 2-dimensional coordinate system.

7. A mask method of masking a camera screen by using an image device including an imaging element which image device is mountable to a rotative table and for masking a partial area of a picture to be displayed on the camera screen so as not to be seen which picture has been captured by the imaging element, comprising:

a first step of obtaining PAN and TILT rotation angles of said rotative table and a zoom position;

a second step of calculating coordinates of corners of a first mask area on an image plane defined by said imaging element which coordinates is in a 3-dimensional coordinate system having an origin through which a central axis of a rotation for the PAN rotation angle and another central axis of a rotation for the TILT rotation angle pass;

a third step of calculating coordinates of corners of a second mask area on said camera screen in a 2-dimensional coordinate system from said coordinates of the corners of said first mask area calculated by said second step by using a relation that distances between a plurality of corners of said camera screen and each corner of said second mask area are proportional to distances between a plurality of corners of said image plane and each corner of said first mask area with a constant ratio, respectively; and

a fourth step of adding a mask signal to a signal of the picture to be displayed on said camera screen so that the picture in said second mask area calculated by said third step is not able to be seen.

8. A mask method of masking a camera screen as claimed in claim 7, wherein said second step comprises:

a step of calculating a first information of coordinates of the corners of said first mask area on said image plane positioned in the state that one coordinate axis of three coordinate axes in said 3-dimensional coordinate system passes through a center of and perpendicular to said image plane and when said zoom position is a preset position said image plane is positioned at a position with a coordinate value on said one coordinate axis which coordinate value is corresponding to said preset position;

a step of calculating and storing a second information to a memory section which second information is coordinates of the corners of said first mask area which coordinates are calculated by converting said first information into said second information for rotations based on PAN and TILT rotation angles of said imaging element as a result of a PAN rotation and a TILT rotation; and

a step of calculating coordinates of the corners of said first mask area which coordinates are those of intersections at each of which intersections each straight line connecting said origin and each corner of said first mask area with said second information derived from said memory section, and said image plane at a present time after a zooming and PAN and TILT rotations, intersect.

9. A mask method of masking a camera screen as claimed in claim 7, further comprising the following step between said third and fourth steps, which following step is of converting said second mask area calculated by said third step into a rectangular area having two sides each of which is parallel with each coordinate axis in said 2-dimensional coordinate system of said camera screen and circumscribes a contour of said second mask area in case that said contour is not a rectangle having a side parallel with a coordinate axis in said 2-dimensional coordinate system.