GB2036369A

GB2036369A - Sub-titling Cinematograph Films

Info

Publication number: GB2036369A
Application number: GB7942589A
Authority: GB
Original assignee: ORNSBY CO Ltd
Current assignee: ORNSBY CO Ltd
Priority date: 1978-12-13
Filing date: 1979-12-11
Publication date: 1980-06-25
Also published as: GB2036369B

Abstract

Sub-titles are added to a finished cinematograph film (print) by the action of an energy beam e.g. laser beam, caused by computer control to write the sub-titles on selected frames. The beam energy removes parts of the developed image in the form of the sub-title characters while a frame is stationary in the gate. Character line thickness is achieved by causing a focused laser spot to define a series of overlapping circles.

Description

SPECIFICATION Sub-Titling Cinematograph Films This invention relates to a method of sub-titling cinematograph films.

A part of the cinematograph film distributing industry is concerned with the addition, to films, of sub-titles consisting of legible characters incorporated in selected frames to represent and convey a desired message. For example, the principal elements of a dialogue in a sound track may be displayed, and this may include translation from one language to another.

To this end, it has been proposed to treat film prints by means of a printing process involving the preparation by etching of a series of printing plates, called cliches, one for each different subtitle. These cliches are applied to the individual frames of the film print under pressure. This process also involves preliminary and subsequent treatment of the film print with other chemicals and has the disadvantages of being time consuming and involving considerable risk of a film print being rendered useless in the event of an operator error during the process.

According to the present invention, there is provided a method of sub-titling a cinematograph film, wherein a beam of energy is caused to remove material having the form of sub-title characters from a surface of the film.

Further, according to the present invention, there is provided apparatus for sub-titling a cinematograph film, comprising a film transport means, a source of a beam of energy, a beam deflecting means operable to direct the beam on to a surface of a film when placed in the film transport means and to deflect the beam for writing sub-title characters, and computing means for co-ordinating operation of the film transport means and the beam deflecting means to write predetermined sub-title characters on selected frames by removal of material from said surface.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings.

Figure 1 is a diagrammatic representation, partly in block diagram form, of apparatus for subtitling a cinematograph film according to the method of the present invention; Figure 2 is a three dimensional diagrammatic representation of part of the arrangement of Figure 1 and to a different scale from Figure 1; and Figure 3 is an illustration showing the formation of a sub-title character in accordance with the present invention.

In the drawings, a cinematograph film print 10 to which sub-titles are to be added is transferred from a reel 11 to a take-up reel 12 through a film transport means in the form of an intermittent film transport mechanism 13 operation of which is effected by a film transport controller 14. The film transport 13 may be a proprietary brand of cine camera used without any lens, and adapted for operation by the controller 14. The film transport 13 is mounted on a vibration-free table 15 which also supports a laser beam deflection module 16 into which a laser beam 17 is directed from a laser head 18 by way of an optional deflector 19. The deflection module 16 focuses the laser beam 17 to a'spot on the surface of the film 10.The deflection module 16 contains optical, mechanical and electronic components required for the deflection and modulation (control of intensity) of the laser beam. The laser beam can be suppressed to enable invisible moves to position the spot on the surface of the film 10 without affecting the film surface between moves. Within the deflection module, the laser beam is deflected by a two-stage deflection system, the combined effect of the two stages being to produce X-Y vector deflections in the plane of the film 10 in the film transport 13. The laser beam 17 is focused to define a spot approximately 15 micrometres diameter on the surface of the film 10. The distance between the film transport 13 and the deflection module 16 is approximately 670 millimitres.

The laser head 18 is preferably an Argon Ion laser having a nominal power rating of 4 Watts.

The optics for the laser system are selected for operation in "all lines" mode.

The film transport controller 14 and the deflection module 16 are operable in response to outputs from a computer 22 which is associated with a control panel and visual display unit 23 and a data store 24, for example, a magnetic tape transport and controller.

The method of sub-titling and the operation of the apparatus described above is as follows. The process of creating the original sub-title data does not form part of the present invention, and it may be assumed that such original data has been prepared, converted to digital form and placed in the data store 24. It may also be assumed that the computer 22 and control 23 incorporate software created using conventional techniques to enable the deflection module 16 to deflect the laser beam 17 as required.

The sub-titling method in accordance with the present invention comprises essentially the removal of material having the form of the requisite sub-title characters from the surface of the film. More particularly, that surface of the film 10 constituted by the developed image consisting of regions varying from light to dark is sub-titled by the removal of parts of the developed image thereby to leave clear areas in the form of the subtitle characters which, on projection viewing of the film, allow projector light to project bright sub-title characters on the projection screen. The form of each sub-title character is created by a writing action of the laser beam 1 7 under the control of the deflection module 16 to which the appropriate X-Y co-ordinates for the writing movements are supplied from the data store 24 via the computer 22.The film 10 is held stationary during the writing of each sub-title, and is advanced as required by the film transport controller 14 in response to instructions from the computer 22.

In each sub-title character, the line width required is approximately 0.8 millimetres. It is possible to achieve this line width by using a laser spot having a corresponding diameter or by repetitions with offsets. However, improved results are obtained by using the much smaller laser spot diameter of 1 5 micrometres and causing this "writing spot" to draw a series of overlapping small circles instead of a straight line.

This mode of operation is illustrated in Figure 3 wherein the path centrelines for the writing paths of the letter A are indicated by reference numeral 25. The writing spot is indicated by reference numeral 26, and a typical "circle" by reference numeral 27. In Figure 3, the letter A is shown as being partly formed at the lower portion of the left leg. An advantage of using this technique is that the extremities of the sub-title characters are rounded in conformance with traditional patterns.

The "circles" are generated electronically by specially designed circuits and do not involve any additional computing power. The circle diameter is chosen to produce a "line thickness" slightly greater than in conventional sub-titles in order to obtain the same apparent thickness when projected. Since dark areas of the developed image absorb more light than do clear areas, the optimum exposure (the amount of laser energy per unit area absorbed by the developed image) for acceptable sub-titles varies with the image density. A compromise exposure can be achieved to give acceptable results on both light and dark areas. Using the laser specified above, the clearest sub-title characters are produced by writing with the laser beam at a power level of approximately 2 Watts, and repeating (re-writing superimposed) the characters five times.

Modifications of the sub-titling method and apparatus described above within the scope of the appended claims include the use of different sources of energy for the removal of material in the form of sub-title characters from a surface of the film. For example, lasers producing different wavelengths at different power levels may be used to achieve an increase in sub-titling speed.

Also, it is envisaged that the sub-titling method can be effected by means of a beam of electrons.

Claims

1. A method of sub-titling a cinematograph film, wherein a beam of energy is caused to remove material having the form of sub-title characters from a surface of the film.

2. The method of claim 1, wherein the beam of energy is caused to write the form of each character by a beam deflecting means.

3. The method of claim 2, wherein operation of the beam deflecting means is controlled by an output from a computer.

4. The method according to any one of the preceding claims, wherein the beam is focused to a spot on the film surface, and the deflecting means is operated so that during the writing of each character said spot moves on circular paths so as to define a series of overlapping circles whose centres lie along the centre of the writing path.

5. The method according to any one of the preceding claims, wherein a complete sub-title or sub-title character is re-written superimposed at least once on each frame being sub-titled.

6. The method according to any one of the preceding claims, wherein the said surface of the film is that surface defined by the developed image.

7. The method according to any one of the preceding claims, wherein the beam of energy is produced by a laser.

8. Apparatus for sub-titling a cinematograph film, comprising a film transport means, a source of a beam of energy, a beam deflecting means operable to direct the beam on to a surface of a film when placed in the film transport means and to deflect the beam for writing sub-title characters, and computing means for coordinating operation of the film transport means and the beam deflecting means to write predetermined sub-title characters on selected frames by removal of material from said surface.

9. Apparatus according to claim 8, wherein the said source of a beam of energy is a laser.

10. A method of sub-titling a cinematograph film, substantially as hereinbefore described with reference to the accompanying drawings.

1 Apparatus for sub-titling a cinematograph film, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.