JPH04320242A - Reproduction device for optical digital sound recording - Google Patents

Abstract

PURPOSE:To read and reproduce an optically and digitally recorded sound during the traveling of a film by detecting accumulated charges as a time-series signal by transferring them in order. CONSTITUTION:The reproduction device has a pulse-lit light source 8, an irradiation optical system 9, a charge storage type image pickup tube 11 such as a CCD, and an objective 10. A data block which is recorded between perforations is lighted and projected by pulse lighting and accumulated charges are read as the time-series signal until a next block is projected. A digital sound signal which is recorded at intervals is detected as a still image during the traveling of the film and read out as a continuous sound signal. Further, a reader can easily be fitted to a conventional projector and reads and reproduces an analog sound track at the same time, so the reader can be utilized to not only digitize sound recording, but also increase sound recording channels.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reproducing optical digital recordings, and more particularly to an apparatus for reproducing audio signals digitally recorded on motion picture film.

0002

2. Description of the Related Art Conventionally, audio signals recorded on motion picture films have been optically or magnetically recorded as analog signals on the soundtrack between the video and the perforations. However, it is natural that the playback quality of the audio signals recorded on these soundtracks cannot be prevented from deteriorating from the time the film is first screened due to dirt, scratches on the film, etc. I could not do it.

0003

It is clear that in order to prevent such deterioration of sound quality, it is desirable to record and reproduce audio signals as digital signals. However, most movie projectors now have built-in optical or magnetic analog audio signal reproduction devices. For this reason, it is practically impossible to record audio signals on motion picture film as digital signals to the current soundtrack section, as this requires modification of these projectors. Furthermore, it is impossible to provide a digital recording track separate from the conventional soundtrack due to film space limitations.

For this reason, attempts have begun to optically record digital signals using black and white dots arranged two-dimensionally in the spaces between the perforations used to drive the film. This audio signal is recorded as discrete signals separated by perforations, and in terms of the amount of information, signals arranged one-dimensionally along the film running direction do not have enough capacity. There is no choice but to create a two-dimensional record that is also arranged in a direction perpendicular to the running direction. The present invention
The present invention aims to provide a device for reproducing such recorded signals, which has not been seen in the past.

[0005]

[Means for solving the problem] In order to achieve the above purpose,
In the present invention, in order to reproduce the digital signals optically recorded between the perforations, the signal recording section of the continuously running film is illuminated with a pulsed light source such as a xenon discharge tube, and the data block image is transferred to a CCD or the like. The accumulated charge is projected onto the photosensitive surface of a charge storage type image pickup tube and detected as a time-series signal by sequentially transferring the accumulated charge until the next block is projected.

[0006]

[Operation] First, let us consider the recording of the signal to be reproduced. FIG. 2 shows the case of digital recording on a 35 mm film, and the dimensions of the digital data block 3 recorded between the perforations 2 of the film 1 are maximum 2.0×1.
It can be seen as 8mm. The spacing between perforations is approximately 2.
Although it is 9 mm, the edge of the perforation is easily damaged by the feed dog, and if the block size is larger than this, the data may be damaged due to damage. When recording dots of size 10μ x 10μ in this area, 1
It is possible to record 36 Kbit in a block. if,
Even if the block size is set to 1.7 x 1.4 mm for safety, if the dot size is narrowed down to 5 μ x 5 μ, the result will be 95.2 mm.
Kbit recording is possible, and in any case, the amount of information that can be recorded in one block is about this amount, and it can be sufficiently handled by a CCD or the like with nearly 200,000 pixels. and,
In a movie, 24 frames are projected per second, and each frame has four perforations, so 96 data blocks must be detected and reproduced per second. Therefore, the repetition time for block detection is 10.4 ms. In addition, in FIG. 2, 4 is a video part, and 5 is a soundtrack. To read such two-dimensionally arranged data, it is common to scan with a light beam, but assuming that the film is running continuously, the time it takes for the above data block to pass the reading position is about 3. The scanning time is 9 ms, and it is impossible to scan all the data in the block within the above time because the reading light beam must be narrowed down and the amount of light is insufficient. For this reason, a continuously running data block is illuminated by a pulsed light source with a light emission time of 1 to 2 ms or less, and the data block image is projected onto the photosensitive surface of a charge storage type image pickup tube such as a CCD, and the data block image is projected onto the photosensitive surface of a charge storage type image pickup tube such as a CCD. A continuous audio signal can be obtained by sequentially transferring the accumulated electricity in between and detecting it as a time-series signal.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reproducing apparatus of the present invention will be explained in detail below by way of embodiments. FIG. 1 is a conceptual diagram showing an example of a data block detection section. Most movie projectors advance the film intermittently, but outside the loop provided before and after the aperture gate, the film is continuously advanced.The audio reading section is located in this continuous advance section, which is different from conventional soundtracks. Same as reading. The film 1 is placed at a gate 6 in order to prevent it from shifting to the left or right in the reading section.
run inside. The shoe 7 is closed after the film is loaded to prevent the film from escaping from the gate. The gates and shoes are provided with windows 6', 7' for reading data block corresponding positions.

The reading optical system includes a xenon discharge tube 8 which is a light source, a condensing lens 9 which condenses light from the light source to illuminate the data block, a reading objective lens 10, and a CC.
It consists of a charge accumulation type image pickup tube 11 such as D or Vidicon (trademark). The pulsed light emission time of a xenon discharge tube is 1 to 2 ms.
However, when a shorter light emission time is required, an appropriate light source such as a pulsed light emitting laser can be used. Further, by enlarging the image formed by the objective lens 10 to fill the entire photosensitive surface of the image pickup tube 11, small data can be easily read. However, considering the displacement of data blocks due to damage to the edges of the perforations, it is better to set the size to leave an appropriate margin.

In the figure, reference numeral 12 denotes a constant speed sprocket for transporting the film, and a position detection device 13 magnetically detects teeth 14 of the sprocket to control the light emission timing of the light source 8. It goes without saying that this timing may be detected by other methods, such as optically detecting the position of the perforation. For this position detection, tooth 1
Although some errors occur due to errors in the shape of No. 4, damage to the edges of the perforations, etc., no problems occur because reading is started by the reading start signal input at the beginning of the data block. Further, although there is a problem that the amount of data is halved, in consideration of data reliability, bi-phase may be adopted in which inversion at the middle of the signal is set to 1.

0010

As described above, the optical digital recording playback apparatus of the present invention can detect digital audio signals recorded intermittently as still images while the film is running, and read them as continuous audio signals. What's more, the reader can be easily attached to conventional projection equipment and can be read and played simultaneously with a conventional analogue soundtrack, making it possible to not only digitize conventional audio recordings but also increase recording channels. It can also be used for.

[Brief explanation of drawings]

FIG. 1: 1 of the data block detection unit of the playback device of the present invention.
Conceptual diagram showing an example

[Figure 2] Conceptual diagram of data blocks when digitally recorded on 35mm film

[Explanation of symbols] 1 Film 2. Perforation 3 Digital data block 4 Video department 5 Soundtrack 6 Gate 7 Shoe 6’, 7’ reading window 8. Xenon discharge tube 9 Condensing lens 10 Reading objective lens 11 CCD 12 Constant speed sprocket 13 Position detection device 14 Teeth

Claims (2)

[Claims] Claim 1: In order to reproduce the digital signals optically recorded between the perforations, the signal recording section of the continuously running film is illuminated by a pulsed light source, and the data block image is exposed to the light of a charge storage type image pickup tube. An optical digital recording playback device characterized by detecting a time-series signal by projecting it onto a surface and sequentially transferring accumulated electricity until the projection of the next block. 2. A pulse lighting light source, an irradiation optical system that illuminates the perforation, a charge storage type image pickup tube, an objective lens that images the perforation on a photosensitive surface of the image pickup tube,
2. The reproduction of optical digital recording according to claim 1, comprising a perforation position detection device and a lighting control circuit for the pulsed lighting light source, and illuminates data blocks recorded between the perforations by pulsed lighting in response to a perforation position signal. Device