Window Generating Apparatus for Use in a Video Camera

The present invention relates to an editing apparatus for use in a video camera; and, more particularly, to a picture editing apparatus for use in a video camera for producing a window and a blank area within a picture.

As well known, video cameras carry a small screen TV monitor through which all four edges of a picture can be seen by the camera operator, referred to as a viewfinder, and a recording unit. The viewfinder is driven directly from the video output of the video camera, which permits the operator to see what the camera sees for the purpose of target framing and optical focus adjustment.

With the increasingly wide use of video cameras, there have been need felt to have a device provided in the camera which would allow the operation to edit the picture to be recorded in the recording unit is edited, i.e., edge portions of the picture are covered or moved for the purpose of accentuating a particular area within the picture and the covered area is whitened or blackened as if viewing a moving picture through a picture frame. Such editing, however, is difficult to be performed since a high level of skill is required.

It is, therefore, an object of the invention to provide an apparatus for use in a video camera for editing a picture by providing a window for a particular area and a blank area within the picture.

It is another object of the invention to provide an apparatus for controlling the size of the window within the picture.

It is a further object of the invention to provide an apparatus for presenting the blank area in a white or a black makeup.

In accordance with the present invention, there is provided a picture editing apparatus capable of providing a window and a blank area within a picture for use in a video camera generating a video signal with successive video lines, which comprises a selection button for generating a selection signal to select a vertical length and a horizontal width of the window; a synchronization signal generator for generating synchronization signals; a control unit, in response to the selection signal, for processing the synchronization signals to generate a window signal; a window generator, in response to the window signal, for processing the video signal to derive the window and the blank area.

The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a schematic block diagram of an apparatus for editing a picture to be televised or recorded by way of producing a window and a blank area within the picture in accordance with the present invention;

FIG. 2 shows exemplary patterns for the window and the blank area;

FIG. 3 illustrates the selection button block of FIG. 1 detail;

FIG. 4 represents a flow diagram explaining the operation the control unit shown in FIG. 1;

FIG. 5 describes the switch circuit shown in FIG. 1; and

FIGS. 6A-6C offer an exemplary window signal generated from the control unit shown in FIG. 1 .

Referring to FIG. 1, there is shown a block diagram of an apparatus for use in a video camera, having a viewfinder (not shown) and a recording unit (not shown), which is capable of editing a picture from the video camera in accordance with the present invention. In a video camera, a video signal is generated from a pick-up device, a CCD (charge coupled device) imager and an appropriate scanning device which scans an object projected on the pick-up device to produce successive video lines constituting the video signal.

The video signal is provided through line 2 to a window generator 100 for the processing thereof in accordance with the present invention. The resultant edited video signal from the editing apparatus is supplied through line 6 to the viewfinder for the viewing of the edited picture and the recording unit for recording the edited picture. For explanatory purpose, the picture to be seen through the viewfinder is exemplarily shown in FIG. 2. As depicted, the picture within the viewfinder has a particular area or window 33 with video information and a blank area 36 without any video information. The window 33 has a vertical length from a top position ("H.sub.start ") to a bottom position ("H.sub.end ") and a horizontal width from a left side position ("T.sub.start") to a right side position ("T.sub.end"). In accordance with the present invention, the vertical length may be determined by the number of video lines from the H.sub.start to the H.sub.end. And the horizontal width may be determined by a running time taken to sweep a video line between the T.sub.start and the T.sub.end. That is, when the time taken to generate a video line is divided into a plurality of time intervals, the running time corresponds to the number of the intervals between the T.sub.start to the T.sub.end. The vertical length and the horizontal width are optionally selected by a selection button block 50.

FIG. 3 shows the selection button block 50 which provides a selection signal to arbitrarily settle the size of the window. The selection button block 50 has a plurality of selection keys 51 to 55. The top position and bottom position selection buttons 51 and 52 are used to select the values of the H.sub.start and the H.sub.end from an upper end and a lower end of the picture by depressing the buttons 51 and 52 for a require number of times. The left side position and right side position selection buttons 53 and 54 are used to select the values of the T.sub.start and the T.sub.end from a left end and a right end of the picture by depressing the buttons 53 and 54 for a require number of times. In this connection, the H.sub.end and T.sub.end are calculated by subtracting the number of depression times of the buttons 52 and 54 from default values, respectively. For example, the default value for the H.sub.start, in case of NTSC format, may be a value of "262" which corresponds to the number of video lines consistituting a half frame. Similarly, the default value for T.sub.end may be the number of pixels in a video line. Accordingly, each of time intervals may correspond to the number of the pixels. The selected values from the selection block 50 are provided to a control unit 70.

A synchronization ("sync") signal generator 80 generates horizontal and vertical sync signals and then supplies them to the control unit 70. The control unit 70, in response to the selection signal from the selection button block 50, derives a window signal from the sync signals, wherein the window signal is used to define the window and the blank area. The operation of the control unit 70 will now be described with reference to FIG. 4 as follows.

In step 401, the control unit 70 begins to count the number of the horizontal sync signals, H.sub.n, for each vertical sync signal as shown in FIG. 6A. And then, in steps 402 and 404, it is determined that the counted number H.sub.n is within or outside the range between the H.sub.start and H.sub.end by comparing it with each of the values H.sub.start and H.sub.end. Thereafter, control goes to step 403 where the control unit 70 issues a first blank signal of a logic low level ("L") to the window generator 100 if the counted number H.sub.n is outside the range between the H.sub.start and H.sub.end, whereas control flows to step 405 if the counted number H.sub.n is within the range between the H.sub.start and H.sub.end.

In step 405, the control unit 70 begins to count the number of time intervals, T.sub.n, for each horizontal sync signal as shown in FIG. 6B. And then, in steps 406 and 407, it is determined that the counted number T.sub.n is within or outside the range between the values Tstart and T.sub.end by comparing it with the values T.sub.start and T.sub.end. Thereafter, the control unit 70 provides a second blank signal of the logic low level as in step 403 to the window generator 100 if the counted number T.sub.n is other than the values of the T.sub.start and the T.sub.end. If the counted number T.sub.n is within the range between the values Tstart and T.sub.end, control flows to step 408 where the control unit 70 issues a picture selection signal of a logic high level ("H") to the window generator 100. The first and the second blank signal are logically combined along with the picture selection signal to produce the window signal which alternates the blank signal section "B" and the picture selection section "P" as shown in FIG. 6C.

Referring back to FIG. 1, the window generator 100 is shown to include a color and luminance separator 10. The color and luminance separator 10 separates a color signal and a luminance signal from the video signal on line 2. The color signal is supplied to a color gain controller 22 and the luminance signal is supplied to a luminance gain controller 24 and then a set-up adjustor 26. The color gain controller 22 serves to control the color signal by varying the amplitude level thereof and the luminance gain controller 24 serves to control the luminance signal by varying the amplitude level thereof. The set-up adjustor 26 serves to control the luminance signal from the luminance gain controller by adjusting the so-called set-up level thereof. On the other hand, the window signal from the control unit 70 is applied through line 8 to the color gain controller 22 and a switch circuit 30. In response to the window signal, the color gain controller 22 controls the amplitude level to a lowest level so that the color component of the color signal is attenuated at each section B with a logic low level of the window signal. The switch circuit 30, as shown in FIG. 5, is switched by a white and black selection button 32 which provides a switching control signal (W/B) to the switch circuit 30 and thereby selectively provides the window signal to the luminance gain controller 24 or the set-up adjustor 26. When the window signal is applied to the luminance gain controller 24 through the switch circuit 30, e.g., at the "off" state of the white and black selection button 32, the luminance gain controller 24 attenuates the amplitude level of the luminance signal to a lowest level at each section B of the window signal, whereby the blank area is blackened. However, if the window signal is provided to the set-up level adjustor 26 through the switch circuit 30, e.g., at the "on" state of the white and black selection button 32, the set-up level adjustor 26 increases the set-up level of the luminance signal to a highest level at each section B of the window signal, which results in a white makeup of the blank area.

The horizontal and vertical synchronization signals from the sync signal generator 80 are also provided to a mixer circuit 40 in which the sync signals are mixed with the gain controlled luminance signal from the luminance gain controller 24 or the set-up adjusted luminance signal from the set-up adjustor 26. The output of the mixer circuit 40 and the gain controlled color signal from the color gain controller 22 are combined at an adder 45 which then provides a composite video signal to the viewfinder or the recording unit, resulting in the edited picture as shown in FIG. 2.

While the present invention has been shown and described with respect to the preferred embodiments, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.