JPH073743B2 - Frame search device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is more desirable than a video signal (video signal) in frame units reproduced from a helical scan type magnetic recording / reproducing apparatus such as a video tape recorder. Related to a frame search device that searches for frames of
The present invention relates to a frame search device suitable for additional use in a video printer.

(Technical background) In recent years, a video printer that prints and outputs an image from a video tape recorder (VTR) or a television receiver (TV) has been researched, developed, and commercialized. As shown in FIG. 8, this video printer converts a video signal supplied from a VTR or TV into digital data and stores the data for one frame (consisting of two feeds) in a frame memory in one hour. . Next, the data is sequentially read from the frame memory line by line (returned to an analog signal), and an image for one screen is printed on the recording paper by the printing means.

That is, the video signal is one frame in two fields,
That is, one screen is configured, the operating speed of the printing means is extremely slow compared to the transmission frequency of the video signal, and when the video signal is a composite signal,
Separated into luminance and color components, R, G, and
As described above, the frame memory is provided in the video printer from the viewpoint of generating the B signal.

Then, while monitoring images (moving images) that are continuously reproduced, a desired frame is searched for and the image is taken into the frame memory (as a still image) by operating a write switch or the like.

(Prior arts and problems to be solved by the invention) As frame search methods, (a) conventional VT for business use
In R, the video signal is a VITC signal (frame address signal)
When additionally recorded, the frame of the image was searched by the address data obtained from the VITC signal during playback.

On the other hand, the above V for consumer VTRs used in ordinary households
The addition of the ITC signal function increases the cost and cannot be adopted. In addition, since it is necessary to add a VITC signal to a magnetic tape that has already been recorded and re-record it, it is troublesome and the image is deteriorated.

(B) It is also possible to search for a desired frame by a reproduction method such as so-called frame advance / still (still). However, in an image obtained by a reproduction method such as frame advance or still (still), as is clear from the explanatory diagram shown in FIG. 9, the inclination of the track during recording is different from the inclination of the head scan during reproduction. Therefore, only an image with poor image quality containing noise can be obtained.

Therefore, a desired frame is searched while monitoring a moving image obtained by normal reproduction, but the timing of loading into the frame memory is difficult and the search accuracy is extremely poor.

(Means for Solving the Problems) In order to solve the above problems, the present invention relates to a frame-based video signal reproduced by a helical scan type magnetic recording / reproducing apparatus in which a control pulse is recorded in the longitudinal direction of a magnetic tape. A frame retrieval device for retrieving a desired frame and storing it in a frame memory, means for rewriting a duty ratio of a control pulse on a magnetic tape to set a reference point, and storing the reference point in the frame memory Means for measuring the number of frames up to, a means for generating the number of search frames by inputting the number of frame differences between the frames stored in the frame memory and a desired frame, and the number of search frames from the reference point. And a means for storing the video signal in the frame memory in the frame memory. .

(Embodiment) An embodiment of the frame search device according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an example in which a frame search device is realized by a system controller (microcomputer) and added to a video tape recorder, and FIG. 2 is a flowchart showing the operation of the frame search device executed by the system controller. FIG. 3 is an explanatory diagram showing the operation of the video tape recorder by the frame search device.

First, the configuration of the frame search device will be described with reference to FIG.

Reference numeral 1 is a video tape recorder (hereinafter referred to as VTR) to which a frame search device is added. Video signals are recorded and reproduced on a magnetic tape by a known helical scan method, and audio signals and control signals are provided in the longitudinal direction of the magnetic tape. (Control pulse) is recorded and reproduced. Reference numeral 2 denotes a system controller (for example, a micro computer, hereinafter referred to as a syscon) that executes the operation of the frame search device, and has an input port group In and an output port group.
Has On. The VTR1 side of the frame search mode switch S _m, is switched from the normal mode to the frame search mode, VTR1 enters under the control of the system controller 2, VTR1 by a control signal from the output port of the system controller 2 is reproduced,
(Pause) Operations such as stop, rewind, and fast forward are performed. Furthermore, the control pulse from VTR1 is
The presence / absence of the control pulse (and the duty ratio) is input to the syscon 2 and is input to the syscon 2.
The control signal of VTR1 is rewritten by the control signal of (1) (a control pulse having a new duty ratio, for example, a VISS signal described later is superimposed).

On the other hand, the video output from the VTR 1 is converted from an analog signal to a digital signal by the AD converter 4 and written in the frame memory 5, and the video signal stored in the frame memory 5 is constantly read out at a constant cycle and is switched. It is input to the DA converter 7 via 6. The DA converter 7 converts the digital signal into an analog signal again, reproduces it as an image on the monitor 8, and sends it to a printing device (not shown). The switch 6 is a reproduction screen switching switch of the monitor 8. The memory side reproduces the image stored in the frame memory 5, and the video side reproduces the video output from the VTR 1 as it is. The writing timing to the frame memory 5 and the switching of the switch 6 are performed by the system controller 2
It is controlled by a control signal from the output port of the.

Further, the video output of VTR1 is input to the frame detector 9, the sync signal in the video signal is detected, and is input to the counter of the syscon 2 as a frame pulse. switch
SW ₁ and SW ₂ are frame search switches input to the system controller 2, and 10 is a keyboard for inputting numerical values.

Here, the control pulse of VTR1 will be described.

Fig. 4 shows the magnetic tape format of the helical scan type VTR. An inclined video track 112 is formed on the magnetic tape 111, an audio track 113 is formed on the upper side in the longitudinal direction, and a control track 114 is formed on the lower side in the longitudinal direction.

A control pulse is recorded on the control track 114. The control pulse (CTL pulse) is a 30 Hz pulse synchronized with the fall of the vertical synchronizing signal of the input video signal as shown in FIG. 5, and is recorded on the magnetic tape 111 at the same time as the video / audio signal. Magnetic tape 111
At the time of reproduction from, the control pulse is also reproduced at the same time, and the rising portion of the pulse is detected and used for tape feed phase control (servo control).

Furthermore, the duty ratio is changed as shown in FIGS. 6 (A) and (B) at the trailing edge of the control pulse, and the control pulse with a duty ratio of 60% is set to "0".
A control pulse having a duty ratio of 27.5% is used as "1" pulse data in the pulse data, and is also used for inserting data for cueing the magnetic tape 1.

As a position reference signal using such data, there is already the VISS format as shown in FIG.

A control pulse (that is, data "0") having a duty ratio of 60% has already been written in the control track on the magnetic tape on which the video signal is recorded. The rewriting of the control pulse is to rewrite only the falling portion of the control pulse while reproducing the rising portion of the control pulse for use in servo control.

That is, when the syscon 2 turns on the VISS terminal and the MARK terminal of the VTR 1, the VISS signal is superimposed on the magnetic tape.
When the VISS signal is superimposed, the write signal to the magnetic head is RE
It is input to the detector 3b as a C control pulse, and the writing timing of the VISS signal is sent to the syscon 2 by the output of the detector 3b.

During normal reproduction, the control pulse demodulated by VTR1 is input to the detector 3a, and the output of this detector 3a causes
Data of "0" and "1" based on the number of control pulses and the duty ratio of the control pulse is sent to the syscon 2, and the VISS signal at the time of normal reproduction is detected. further,
From VTR1, VISS signal detection pulse at reverse playback is sent to syscon.

When the VISS signal is used as the reference signal, the entire VISS signal or only a part of the VISS signal may be used.

The operation of the frame search device configured as described above will be described. The following operations are executed under the control of the syscon 2.

When the search mode switch S _m of VTR1 is set in the search mode, VTR1 the normal playback operation and become (step 100), for example, in the NTSC system is 30 frames of video per second are reproduced. At this time, the changeover switch 6 is on the video side, and VT
The video signal from R1 is sent to the monitor 8 as it is.

After the running is stabilized for 2 to 3 seconds, the operator looking at the playback screen of the monitor 8 is in front of the target frame.
When SW ₁ is pressed, the reference signal (VISS signal) is written on the magnetic tape and the reference point is set (steps 101, 10).
2). That is, a predetermined number (61) of data "1" having a duty ratio of 25% is superimposed on the already written control pulse (data "0" having a duty ratio of 60%).

At the same time, the reference signal being written is (REC DUTY) detector 3b.
The timing of writing the reference signal is detected by this, and counting of the number of frame pulses is started by the output from the frame detector 9 in accordance with this timing (step 10).
3).

When the operator presses SW ₂ near the desired frame on the playback screen of monitor 8, the frame immediately after is written to frame memory 5, VTR 1 is paused, and the counting of the number of frame pulses is stopped (count Value A), the selector switch 6 is switched to the memory side, and the memory written in the frame memory 5 is sent to the monitor 8 as a still image (steps 104, 105, 106).

Based on the reproduction screen of the monitor 8, the operator determines how many frames the searched frame is before and after the reproduction screen (frame), and inputs the corrected frame number B using the keyboard 10 (step 107). .

For example, if the frame being searched for is about 3 frames later than the frame on the monitor, +3 is input, and if it is about 2 frames before, -2 is input. The count value A and the corrected frame number B are added to obtain the search count value C (step 108).

The VTR1 is reversely reproduced until the reference signal is detected, and the normal reproduction is started from before the reference point (the position where the VISS signal is written) (steps 109, 110, 111). When the reference signal is detected, the number of frame pulses is started to be counted, and when the search count value C is reached, the frame immediately after that is written to the memory and the VTR is temporarily stopped. The changeover switch is changed over to the memory side again, and the frame written in the memory is sent to the monitor as a still image (steps 112, 113,
114,115). If this frame is the desired frame,
The frame search is completed, and the frame (image) in the memory is sent to the next printing device. If it is not the desired frame, the process returns to step 107 and the search is repeated (step 117).

In the above embodiment, the frame pulse number from the frame detector 9 is used as the count value from the reference signal.
The number of control pulses from the detector 3a may be used.

In addition, frame search devices such as Syscon 2 and memory 5
A printing device (printer) not shown, even if it is built into the VTR1
It may be built in or configured as an adapter interposed between the two. If the frame memory 5 is incorporated in the printing apparatus, the frame memory 5 can also be used as a buffer memory of the printing apparatus.

(Effects of the Invention) As described in detail above, according to the frame search device of the present invention, an arbitrary frame of a VTR playback video signal is searched and extracted from the normal playback state without making the VTR still playback. Since it can be stored in the memory, the video signal of the desired frame can be surely retrieved with high accuracy.

Even if the frame of the video signal initially selected is not the desired one, it is possible to search for the frame again by operating the switch or the like based on the recorded reference point (reference signal). Easy to search frames.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an embodiment of a frame search device according to the present invention, in which the frame search device is realized by a system controller (microcomputer) and is added to a video tape recorder. 2 and 3 are flowcharts showing the operation of the frame search device executed by the system controller, FIG. 3 is an explanatory view showing the operation of the video tape recorder by the frame search device, and FIGS. 4 to 7 are control pulses. FIG. 8 and FIG. 9 are views for explaining the conventional problems. 1 ... Video tape recorder (VTR), 2 ... System controller, 5 ... (frame) memory, 10 ... Keyboard.

Claims (1)

[Claims] 1. A frame search in which a desired frame is searched for from a video signal of a frame unit reproduced by a helical scan type magnetic recording / reproducing apparatus in which a control pulse is recorded in a longitudinal direction of a magnetic tape and is stored in a frame memory. A device for rewriting the duty ratio of a control pulse on a magnetic tape to set a reference point, a unit for measuring the number of frames from the reference point to storing in the frame memory, and a unit for storing in the frame memory And a means for generating a search frame number by inputting the number of frame differences between the selected frame and a desired frame, and a means for storing the search frame number of video signals from the reference point in the frame memory. A frame search device.