JP3036898B2 - Apparatus and method for generating key signal for image synthesis - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image synthesizing key signal generating apparatus for generating, as a key signal, a difference between a picked-up output image signal of a foreground subject and a previously stored wide-angle foreground image. The method of occurrence.

[0002]

SUMMARY OF THE INVENTION The present invention relates to an apparatus and a method for generating a key signal for extracting an arbitrary moving object captured by a camera. It is stored in the frame memory, the changed visual field area is read from the frame memory in accordance with the camera operation when the subject is imaged by the camera, and the difference is compared with the subject image to obtain a difference, thereby following the camera operation. The key signal of the subject can be generated.

[0003]

2. Description of the Related Art Generally, in a difference method using a video mat, an image synthesizing key signal is generated by the configuration shown in FIG. In the conventional technique shown in FIG. 3, a foreground image A, which is a reference in the studio camera 1, is taken into a frame memory 2.

Next, a video B containing a subject is captured from the camera 1 under the same imaging conditions as the reference foreground image A, and the difference from the reference foreground image A in the frame memory 2 is determined by a key signal processing circuit 3.
Is obtained for each pixel unit. In this key signal processing circuit 3,
A key signal C is generated by determining an appropriate threshold value and binarizing the result.

[0005]

As described above, in the above-described key signal generation method using the video mat of the conventional configuration,
The camera could not be operated and had to be stationary.

[0006] However, in general, when a subject is imaged, if the camera is restricted, the degree of freedom of the imaging conditions with respect to the motion of the subject is significantly reduced, and only limited video expression is possible.

It is therefore an object of the present invention to provide an apparatus and a method capable of generating a key signal of an arbitrary subject following a camera operation.

[0008]

According to the present invention, a key signal is output by cutting out a reference foreground image interlocked with the rotation angle of the camera and the magnification of the lens without particularly requiring a blue panel or the like as the background of the foreground subject. And the degree of freedom in imaging is greatly increased.

That is, an image synthesizing key signal generating apparatus according to the present invention comprises: an image storing means for storing wide-angle foreground image information without a subject; and a detecting means for detecting a rotation angle and a lens magnification of an imaging camera. A basic foreground image processing unit that performs a predetermined enlargement, reduction, and cutout process on the wide-angle basic foreground image based on an output of the detection unit and extracts a basic foreground image corresponding to an operation of the imaging camera; A key signal generating means for inputting a foreground image with a subject and a basic foreground image corresponding to the operation of the imaging camera, and outputting a key signal.

Further, according to the method for generating an image synthesizing key signal according to the present invention, a foreground image having no subject is taken in advance.
The reference image is stored in the frame memory, and then the subject is introduced into the foreground image, imaged by the camera, and a difference between the image on the frame memory and the subject is generated. In synthesizing the image, cut out the area corresponding to the change field of view of the frame memory according to the change of the rotation angle of the camera and the lens magnification,
By subjecting the area to enlargement / reduction processing and calculating the difference between this area and the captured image of the foreground object, only the signal of the object part is extracted and a key signal is generated.

[0011]

According to the present invention, a reference foreground image having a wide angle of view is stored, and image processing means such as an enlargement / reduction scroll circuit is used to perform cutout / enlargement / reduction processing according to the pan, tilt, and zoom of the camera. The key signal is obtained by obtaining the key signal by comparing the image with the image including the subject and obtaining the difference.

Therefore, according to the present invention, the camera can be arbitrarily panned, tilted and zoomed in image synthesis by the difference method.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. First, a foreground without a subject is captured by a foreground imaging camera 5.
The image is divided and imaged over a wider range, and these are joined by the frame memory 7 to obtain a basic foreground image A having a wide angle of view.

The pan, tilt, and zoom data are detected by a detection circuit 6 for detecting the rotation angle of the camera 5 and the lens magnification, and are sent to the host computer 8 as needed.

On the other hand, in order to obtain a basic foreground image A 'corresponding to a camera operation from the frame memory 7, an enlargement / reduction scroll / perspective conversion circuit 9 supplies an address signal for accessing the frame memory 7.
That is, the enlargement / reduction scroll / perspective conversion circuit 9 cuts out the image area A ′ in which the reference foreground image is made to correspond to the current field of view under the control of each data relating to the change of the field of view of the camera supplied from the computer 8. ,
It is supplied to the key signal processing circuit 10.

The key signal processing circuit 10 supplies an output image signal B of the foreground imaging camera into which the subject has been introduced. In this key signal processing circuit 10, after performing subtraction for each pixel,
The binarization is performed, and a key signal C is output.

Next, with reference to FIG. 2, a detailed operation of the enlargement / reduction scroll / perspective conversion circuit 9 will be described.

From the wide foreground basic foreground image A to the region image A '
In extracting the data, the horizontal (H) and vertical (V) memory addresses of the image A in the frame memory 7 corresponding to the rotation angle of the camera are stored in the H start address register 12 and the H start address register 12 via the computer bus 11 from the computer 8. Supply to V start address register 13.

Further, an enlargement ratio by the zoom of the camera is supplied to an enlargement ratio register 14. Further, since a perspective is applied to the image A according to the rotation angle of the camera, the horizontal perspective amount and the vertical perspective amount are supplied to the H perspective register 15 and the V perspective register 16 according to the rotation angle, and are used for the perspective conversion. Input to the address calculation circuit 17,
A conversion coefficient corresponding to the rotation angle is obtained.

Each data corresponding to the field of view of the camera is supplied to an address generation circuit 18, and an address signal generated based on these data is supplied to an address input of the frame memory 7 and cut out according to the operation of the camera. A basic foreground image A 'is obtained.

[0022]

As is apparent from the above description, according to the present invention, the difference between the reference foreground image and the foreground subject image when there is no subject previously stored in the frame memory is extracted, and a key signal is generated. Panning the camera when capturing the foreground subject when combining it with other background images
By cutting out the wide-angle reference foreground image on the frame memory in conjunction with the tilt and zoom operations, it is possible to take the difference between the foreground subject image and the reference foreground image,
There is a remarkable effect that a key signal of a subject can be generated without being limited by camera work.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a key signal generation system for image synthesis according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of an enlargement / reduction scroll / perspective conversion circuit.

FIG. 3 is a block diagram schematically showing a conventional image synthesizing key signal generation system.

[Explanation of symbols]

 Reference Signs List 5 imaging camera 6 rotation angle, lens magnification detection circuit 7 frame memory 8 host computer 9 enlargement / reduction scroll / perspective conversion circuit 10 key signal processing circuit 11 computer bus 12 H start address register 13 V start address register 14 enlargement ratio register 15 H perspective Register 16 V Perspective register 17 Perspective conversion address calculation circuit 18 Address generation circuit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaki Hayashi 1-10-11 Kinuta, Setagaya-ku, Tokyo Japan Broadcasting Corporation Research Institute of Broadcasting Technology (56) References JP-A-60-190078 (JP, A) Hei 2-198281 (JP, A) JP-A-3-29472 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/262-5/275

Claims (2)

(57) [Claims] An image storage unit configured to store foreground image information of a wide angle of view without a subject; a detection unit configured to detect a rotation angle and a lens magnification of an imaging camera; and the wide angle of view based on an output of the detection unit. Basic foreground image processing means for subjecting the basic foreground image to predetermined enlargement / reduction / cutout processing to extract a basic foreground image corresponding to the operation of the imaging camera; and a foreground image with a subject and operation of the imaging camera. A key signal generating means for inputting a basic foreground image and outputting a key signal. 2. A foreground image having no subject is captured in advance, its reference image is stored in a frame memory, and then the subject is introduced into the foreground image and captured by a camera. In synthesizing the foreground subject image and the background image by the obtained key signal of the subject, an area corresponding to the changed field of view of the frame memory is cut out according to the change in the rotation angle of the camera and the change in the lens magnification. A method for generating a key signal for image synthesis, wherein a key signal is generated by extracting only a signal of a subject portion by performing a process of enlargement / reduction and calculating a difference between this region and a captured image of a foreground subject.