JPH0149237B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a still image reproducing method for an optical video disc player.

(b) Prior Art Conventionally, an optical video disc player records one frame of video signal per revolution. Therefore, when playing still images, it is sufficient to skip one track for each frame. Jumping over one track is relatively easy, as it only requires detecting the next track center and stopping.

However, the high-definition video signal to be input to a high-definition television has a wide recording band and cannot be recorded in one recording track. Therefore, a video disc record that records a high-quality video signal records one frame worth of video signal over two or three revolutions.

Therefore, in a video disc player that plays back such a video disc record, it is necessary to jump two or three tracks per frame when playing a still image, making it difficult to jump tracks quickly.

(c) Purpose of the Invention Therefore, the present invention provides a novel still image that realizes rapid track skipping when playing still images from a video disk record in which one frame of video signal is recorded over two or more tracks. This paper proposes a method for reproducing images.

(D) Structure of the Invention The present invention provides a recording track that records one frame of a video signal over n revolutions of a spiral recording track (n is an integer of 2 or more) while rotating a video disk record n times per frame. In an optical video disk player that optically reproduces a track jump, a starting pulse for track jumping is supplied to the tracking means in synchronization with a playback vertical synchronizing signal, and a zero cross of the tracking error detection output is detected after the track jump starts. The apparatus is characterized in that a predetermined number of outputs are counted, and after the counting is completed, a braking pulse is applied to the tracking means to reproduce a still image by jumping over n tracks.

(e) Embodiment Hereinafter, an embodiment will be described in which the present invention is applied to an optical video disc player that reproduces one frame of high-quality video signal over two revolutions of a spiral recording track.

The video disc player of this embodiment has a ±1
The optical system includes an optical system that irradiates both sides of the recording track with the following diffracted light to detect the tracking state and reproduces the center of the recording track using the zero-order light, but such an optical system is not explained by those skilled in the art. Since the configuration is well known, illustrations and explanations will be omitted. Further, the tracking mechanism for electromagnetically rotating the tracking mirror in the width direction of the track based on the tracking error detection output is also well known and will not be illustrated and described here.

In this embodiment, the light receiving outputs of tracking sensors S ₁ and S ₂ that receive ±1st-order light are amplified by amplifiers A ₁ and A ₂ and then inputted to a comparison circuit 1, and the comparison outputs are used as tracking outputs and sent to the tracking means. supply to
This is the same as the conventional example in that tracking of the irradiation beam is realized.

In this embodiment, in consideration of the relationship between the irradiation position of the beam relative to the track and the tracking error as shown in FIG. 2, the track records the zero cross of the tracking error from positive to negative after the start of the jumping operation. This method is characterized in that it is detected as the passing of the center of two recording tracks, and this 0-cross point is counted to detect a jump between two recording tracks.

That is, in this embodiment, the detection output of the reproduction sensor So is amplified by the amplifier Ao and then input to the video signal processing circuit 2, and the resulting video signal is input to the vertical synchronization separation circuit 3. Jump command signal detection circuit 4 that inputs a vertical synchronization signal and a video signal
detects the skip command signal inserted in the blanking period immediately after the vertical synchronization signal and issues a skip command output for each frame. In response to this jump command output, the starting pulse generation circuit 5 supplies the tracking means with a starting pulse whose level is sufficiently higher than the tracking error output. The tracking means that receives this starting pulse starts to track inward as schematically shown in FIG.

The 0 cross detection circuit 6, which is activated at the start of still image playback, receives the tracking error output and detects only the 0 cross from positive to negative in the tracking error output. The output is input to a counting circuit 7 which uses the jump command output as a reset input. When this counting circuit 7 counts "2", it supplies a count-up pulse to the braking pulse generating circuit 8. When the count-up pulse is input, the braking pulse generating circuit 8 supplies the tracking means with a braking pulse having a polarity opposite to that of the starting pulse.

In this way, if track jumping is completed after counting two 0-cross points, it becomes possible to jump two recording tracks. In this embodiment, the 0-crossing point from positive to negative, which is the track center, is detected, but when detecting both 0-crossing points, the count-up value of the counting circuit 7 is set to 4 (=2× 2) should be set. Furthermore, instead of recording one frame of video signal on two recording tracks as in this embodiment, a still image can be recorded on a video disk record on three or four recording tracks. When playing back, the count-up value may be set to 3 or 4.

In this example, optical tracking errors are detected, but the output fluctuations (AC component ) may be used as the tracking error detection output, and it goes without saying that such a configuration is included in the present application.

(f) Effects of the Invention Therefore, according to the present invention, it is possible to quickly and reliably jump between a plurality of recording tracks during still image reproduction, and stable still image reproduction is possible.

[Brief explanation of drawings]

Each of the figures shows an embodiment of the present invention. Fig. 1 is a main circuit block diagram, Fig. 2 is an explanatory diagram of tracking position and tracking error output level, and Fig. 3 is a schematic explanation of tracking and track jumping. Figures, respectively, are revealed. Explanation of main drawing numbers, 5... Starting pulse generation circuit,
8... Braking pulse generation circuit, 7... Counting circuit.

Claims (1)

[Claims] 1. One frame of video signal is recorded on a spiral recording track n.
In an optical video disk player that optically reproduces a recorded track while rotating a video disk record recorded over a period of one frame (n is an integer of 2 or more), the recording track is synchronized with a playback vertical synchronization signal. Then, a starting pulse for track jumping is supplied to the tracking means, and after the tracking jump starts, the zero cross detection output of the tracking error detection output is counted, and track jumping is continued until the counted value reaches n, and the track jumping is continued until the counted value reaches n. 1. A still image reproducing method for an optical video disk player, characterized in that when the number of tracks reaches n, a braking pulse is applied to the tracking means to complete jumping over n tracks, thereby reproducing the still image.