GB2097220A - A method for the television scanning of films - Google Patents

Abstract

In a method for the television scanning of films of the Cinemascope format wherein the film is recorded compressed in the horizontal direction of a factor of 2, the video signal is expanded by an appropriate pulsing of storage means and the beginning and end of the reading out operation may be displaced selectively in order to prevent margins without picture content on the viewing screen. In one embodiment, the complete Cinemascope film frame is introduced into a picture store and is read out once again at a reduced pulse frequency after displacement of the beginning of the read out.

Description

SPECIFICATION A method for the television scanning of films State of the art The invention originates from a method for the television scanning of films according to the preamble to the main claim.

Films shot in accordance with the so-called Cinemascope method are compressed by the factor of 2:1 in the horizontal direction with an anamorphotic objective and are recorded, for example, on 35 mm cinematograph film (format: width = 21.385 mm, height = 18.2 mm. Thus, after the subsequent decompression (expansion) a ratio of width to height of 2.35:1 is produced. On the other hand, the television format illustrated on the viewing screen amounts to 4:3 = 1.33:1. Thus, it is not possible to scan so-called Cinemascope films in a television manner without compromises.

One known compromise consists in generating a format of 1.85:1 whereby about 11% is certainly cut off from the picture content on each side and a disturbing margin without picture content appears on the viewing screen above and below the reproduced picture.

With another known method, the film is illustrated at full picture height on the viewing screen. In so doing, there are no disturbing margins but now 22% of the picture content is cut from each side of the picture. Since important picture information for handling can be located in these positions, it has been necessary to displace the important picture sections during the scanning. Mechanical, optical or electronic methods can serve for this purpose. Thus, it is possible to achieve the displacement of the image on the signal electrode with a memory tube film scanner by displacing the projector or by rotating mirrors or prisms. With light spot scanning it is possible to displace the scanning raster electronically.

With a television film scanner provided with semiconductor line sensors (such as described for example in German OS 2921934) or semiconductor area sensors mechanical optical methods such as in memory tube films scanners are also offered. However, these methods are mechanically complicated, susceptible to dust, they impair the quality of the optical image and do not permit the inertialess change in position from one film frame to the following.

Thus, the invention is based on the problem of providing a method for the television scanning of so-called Cinemascope films with the reproduction of the film at full picture height on the viewing screen, in which the displacement of the picture section is carried out purely electronically.

Advantages of the invention The method in accordance with the invention comprising the characterising features of the main claim has the advantage that the displacement of the picture section takes place without inertia and no mechanical complicated, construction susceptible to wear is required.

Advantageous further developments and improvements of the method set forth in the main claim are made possible by the measures set forth in the sub-claims.

Embodiments of the invention are illustrated in the drawing and are described in detail in the following specification.

Figure 1 shows a block circuit diagram for the expansion of the video signal by means of a semiconductor sensor; Figure 2 shows a block circuit diagram for the expansion of the video signal before the picture storage; Figure 3 shows a block circuit diagram for the expansion of the video signal on reading our from the picture memory; Figure 4 shows a block circuit diagram for the expansion of the video signal by means of a line memory after the picture storage; Figure 5 shows a block circuit diagram for a reduced expansion of the video signal after the picture storage; Figure 6 shows a block circuit diagram for the expansion of the video signal before and after the picture storage; Figure 7 shows a block circuit diagram of a further embodiment of the invention; Figure 8 shows a block circuit diagram for carrying out the method in accordance with the invention; and Figure 9 shows various read-out positions of the intermediate stored video signals.

A semiconductor sensor 1, for example a line or area sensor, which is scanning a film not shown in the Figure, is illustrated in Fig.

1. In order to explain the invention, a sensor is simply provided in this block circuit diagram but the use of the invention is not dependent on whether it is a question of film scanning in colour or black and white television. In the case of colour television, three sensors are provided for example instead of the one sensor onto which the light is projected with a colour separating device known per se.

The output signals from the sensor 1 are amplified and if necessary are subjected to various corrections known per se in the television art and which take place in a video processor 2. Then, the signals, up till now analogue signals, are converted into digital signals which takes place with the aid of an analogue/digital converter 3. As is known, digital signals may be well stored and without loss of quality. For this purpose, the output from the analogue/digital converter 3 is connected to an image store 4. The content of a complete television picture, if necessary including the colour information, can be stored in the memory 4. The digital television signals are read out of the memory 4 in accordance with the television standard, are re-converted in a digital/analogue converter 5 into analogue signals and are available at the output 6 from the circuit.

The scanning control of the sensor 1 takes place with the aid of control signals which are generated by a position displacement circuit 7 as well as with the clock pulses T applied to the terminal 8 which, when scanning normal film, are transmitted to the sensor 1 through a switch 9 and with Cinemascope film scanning with displacement of a picture section are transmitted to the sensor 1 through a divider stage 11 and the switch 9. When scanning Cinemascope films according to the format 2.35:1 with displacement of a picture section, the entire width of the film frame is applied to the sensor 1. Moreover, when using line sensors, the position of the entire line is displaced within the transport range of the sensor 1 with the aid of the H pulse.

For reading out the picture elements from the transport range sensor 1, a clock frequency reduced by the factor K, (for example 1.76) is applied to the sensor. Since the digitalising in the converter 3 as well as the storage in the memory 4 takes place at the standard clock frequency corresponding to the television system, only a portion of the sensor picture elements is stored in the memory 4 as an active line. Moreover, the displacement of the picture section takes place with the aid of the position displacement circuit 7 which provides corresponding pulses by adjusting the read-out start point for the transport range and the read in start point for the memory 4.

Thus, a video signal can be derived at the output 6 from the circuit which corresponds to a selected section of the scanned film frame.

With the circuit illustrated in Fig. 2, the expansion of the digital video signal takes place before the picture storage. The colour signals RGB collected by the semiconductor sensors (not illustrated in the figure) have been converted in a matrix (likewise not illustrated) into the luminance signal Y and the two colour difference signals R-Y and B-Y which are applied to the terminals 21 to 23.

These signals are now fed through a respective changeover switch 24, 25 and 26 through a respective low pass circuit 27 or 28, 29 or 31, 32 or 33 to a respective further switch 34, 35 and 36. Moreover, the switches 24 to 26 and 34 to 36 are controlled by a signal applied to the terminal 37 which, according to the film format, changes the switches from the low pass circuits 27, 29, 32 for standard film scanning to the low pass circuits 28, 31, 33 for Cinemascope film scanning so that, in so doing, the band width of 5 MHz still remains in the output signal.

The luminance signal Y as well as each one of the two colour signals R-Y/B-Y = C changed over by the switch 38 are transmitted to the A/D converter 39. The video signals Y, C digitalised in the converter 39 are transmitted to an intermediate memory 41. In this case, the intermediate memory 41 is driven at the same clock frequency f2 during reading in as the A/D converter 39. This clock frequency f2 is provided by a pulse generator 42 which is synchronised with the studio synchronising pulses. The studio synchronising pulses are applied to the terminal 43.

The reading out of the video signal from the intermediate memory 41 takes place at a frequency f3 = 1 /Ke x f2 correspondingly reduced by the expansion factor K,. Furthermore, the picture memory 42 is pulsed at the frequency f3 during reading in of the video signal which is transferred from the intermediate memory 41. The reading out of the video signal from the picture memory 42 is synchronised with the aid of the studio synchronising signal S. The video signal arriving from the memory 42 is transmitted to a D/A converter 44 likewise pulsed at the clock frequency f3 and from the output terminals 45 and 46 of which can be derived the analogue video signal together with the components Y and C.

Moreover, the pulse generator 42 delivers the clock signals T at the frequency f, necessary for the reading out of from the semiconductor sensors, which can be derived from the terminal 47, as well as the H-pulses H1 necessary for the operation of the semiconductor sensors, which can be derived from the terminal 48.

The displacement of the picture section takes place by selecting the picture elements from the intermediate memory 41 by means of a signal provided by the position displace ment circuit 49 and which can be varied by a manual or automatic adjustment of a setting member.

The same parts 21 to 38 already described in Fig. 2 are left out of the circuit according to Fig. 3 for the sake of simplicity and like parts corresponding to those in Fig. 2 are provided with like references. The luminance signal Y as well as the colour signals C are likewise transmitted to the A/D converter 39. The digitised video signals Y and C which are transmitted to a picture memory 51 can be derived at the ouput from the A/D converter 39. The reading in to the picture memory 51 as well as the reading out therefrom and the introduction into an intermediate memory 52 takes place at the same pulse frequency f3 at which the A/D converter 39 is also pulsed.

Thereafter, the intermediate memory 52 can be read out at the frequency f4 = f3/Ke reduced by the expansion factor K,. The posi tion displacement takes place with the aid of the position displacement circuit 49, moreover, during the reading out from the picture memory .51 as a rough adjustment as well as during the introduction into the intermediate memory 52 as a fine adjustment.

The video signals read out from the intermediate memory 52 are transmitted to a picture element interpolator 53 in which the data rate is doubled.

In so doing, a third, intermediately available picture element, is generated from each two adjacent picture elements. The picture element interpolated video signals are then transmitted to a blanking stage 54. The blanking stage 54 is necessary since the video signals stored in the picture memory 51 are still compressed whereby their blanking gaps do not coincide with the standard television blanking gaps. Thus, the blanking signal A3 is derived from the picture memory 51 and is transmitted to the pulse generator 42. The pulse generator 42 processes the blanking signal A3 and delivers a normal blanking signal A4 to the blanking stage 54. Thus, a correspondingly expanded video signal comprising the components Y and C can be derived at the output terminals 45 and 46 from the D/A converter 44.

The circuit according to Fig. 4 differes from that according to Fig. 3 by the fact that a line memory 57 is used instead of the intermediate memory 52 in Fig. 3. In so doing, the video signal comprising the components Y and C digitalised in the A/D converter 39 is transferred into the picture memory 51. The reading out from the picture memory 51 takes place with a pre-shifting by one line on introduction into the line memory 57.

The processing of the video signals in the circuits 39, 51 as well as the introduction into the line memory 57 is carried out at the same pulse frequency f3. The expansion of the video signals is carried out during the reading out from the line memory 57, which takes place at a pulse frequency f4 = f3 X 1 /Ke lower by the expansion factor Ke.

The position displacement is likewise possible with the circuit 49 during the reading out from the line memory 57. Furthermore, a picture element interpolator 53 is also provided which accepts the data at the pulse frequency f4.

The data rate is doubled by the picture element interpolator 53 and the following blanking stage 54 as well as the D/A conterter 44 is thus controlled at the same double introduction pulse frequency 2f4. Thus, a picture signal expanded and displaced in its position can once again be derived at the output terminals 45 and 46.

In the circuit illustrated in Fig. 5, the video signals Y, C applied to the A/D converter 39 have already been expanded by optical or electronic methods by the factor 1.1 8. After digitalising, these expanded video signals are introduced into the picture memory 51, then read out at the same pulse frequency f3 and read into the intermediate memory 52.

In this case, the position displacement takes place once again with the circuit 49 during the reading out from the picture memory 51 and during the introduction into the intermediate memory 52. The video signals are so read out from the intermediate memory 52 that, after each 2 picture elements, a third picture element can be introduced into the following interpolator 58 by the interpolation of two adjacent picture elements. Thus, an expansion in the ratio 1:1.5 is possible with this circuit.

The further processing takes place as already described in the blanking stage 54 and the D/A converter 44. Thus, video signals Y, C with the desired expansion 1:1.77 can be derived at the terminals 45 and 46.

With the circuit illustrated in Fig. 6, both an expansion of the video signal before and after the picture memory 51 is possible. Thus, the video signal applied to the A/D converter 39, for for example during normal film transport (24 or 25 frames per second forwards) can already be expanded in the intermediate memory 61 whereafter the video signal is further processed - as described in Fig. 2. That has the advantage that a hagh resolution can be achieved without widening the picture memory 51.

The other possibility, of expanding the video signal after the picture memory, is preferably used when the film is to be scanned during a still picture or slow searching transport. In that way, jumping of the image during the carrying out of the position displacement is prevented with the aid of the circuit 49. The expansion with the aid of the intermediate memory 62, which includes simultaneously a picture element interpolator, is carried out as descirbed in Figs. 3, 4 or 5.

Thus, expanded video signals Y, C can be derived at the output terminals 45 and 46 and which have been expanded before or after the picture storage according to the type of operation of the film scanner.

In the circuit illustrated in Fig. 7, the expansion of the digital video signal takes place in a picture store 65 receiving the complete Cinemascope film frame. The type of colour signals R,G,B sensed by the semiconductor sensors (not shown in the figure) have been converted in a matrix (likewise not shown) into the luminance signal Y and the two colour difference signals R-Y and B-Y. The luminance signal Y as well as each of the two colour signals R-Y/B-Y = C are transmitted to the A/D converter 39. The video signals Y,C digitalised in the converter 39 are transmitted to the picture store 65 which is actuated during reading in at the same pulse frequency f2 as the A/D converter 39. The reading out of the video signals from the picture store 65 takes place at a frequency f4 = 1 /Ke . 2 correspondingly reduced by the expansion factor Ke.Moreover, the D/A converter 44 is pulsed at the frequency f4. The analogue video signal comprising the components Y and C can then be derived at the output terminals 45 and 46 of the converter 44.

A pulse generator 42, which is synchronised to the studio synchronising pulses S, delivers the pulsed frequencies f2 and f4. The studio synchronising pulses S are applied to the terminal 43. Moreover, the pulse generator 42 delivers the pulse signals at the frequency f1 necessary for the reading out from the semiconductor sensors and which can be derived at the terminal 47, as well as the H pulses H, necessary for operating the semiconductor sensors and which can be derived at the terminal 48.

The displacement of the frame section takes place by the selection of the picture elements in the picture store 65 by means of a signal derived from the position displacement circuit 49 which can be varied by a manual or automatic setting of an adjustment member.

The arrangement described in relation to Fig. 7 has the advantage that, by using an extended picture store receiving a complete Cinemascope film frame for the expansion of the digitalised video signals, further individual memories, such as line memories can be dispensed with.

In the circuit illustrated in Fig. 8, the expansion of the digitalised video signals takes place both before and after the picture storage. The colour signals R, G, B derived from the semiconductor sensors (not illustrated in the figure) have been converted in a matrix (likewise not illustrated) into the luminance signal (Y) and the two colour difference signals C (R-Y/B-Y). After A/D conversion, they exist as digital video signals C and Y at the input to a first intermediate store 61. An expansion of the digital video signals with an expansion factor Ke of for example 1.5, takes place in the intermediate store 61.The thus expanded video signals are then conveyed to a picture store 51 from which they are further conveyed to a second intermediate store 62 for further expansion, for example by the expansion factor Ke = 1.1 73. Thus, video signals C, Y correspondingly expanded by the desired total expansion of 1.76, can be taken from the outputs of the intermediate store 62 and which are then D/A converted before further processing. The ratio of the two expansion factors given by way of example can, of course, be selected as other ratios in accordance with the use and type of the picture store 51.

Moreover, the displacement of the frame section takes place with the aid of a position computer 71 which displaces the read-out positions from the two intermediate stores 61 and 62 with digital control commands (8 bits or 9 bits). Thus, a mutual influencing with respect to the read-out position is also possible with the aid of a feedback of the actual value from the respective intermediate stores 61 and 62 to the position computer 71.

The digitalised DC voltage from an adjusting knob in the desired value stage 72 effecting the displacement of the film section is conveyed to the position computer 71 through a machine computer 73. Moreover, a time code signal, which corresponds to the particular film position number, is conveyed to the machine computer 73 from a time code counter 74. The positional value introduced manually into the desired value stage 72 can also be conveyed selectively to the machine computer 73 by a switch 75 (in the dotted position) through a desired value automatic stage 76 whereby the particular displacement of the picture section is pre-programmable.

Furthermore, the machine computer 73 delivers a control signal to a changeover switch 77 to the input 78 to which is applied a type of operation signal, for example in accordance with the film format and the instantaneous film speed, and the output from which can be connected to various inputs to the position computer 71. Furthermore, the position computer 71 is controlled by the machine computer 73 in accordance with further signals, for example forwards, backwards travel (line 79) or asychronously or synchronously with film speed. Furthermore, the machine computer provides an imput start signal through the line 82 both for the picture store 51 and for the position computer 71. Moreover, the picture store 51 as well as the position computer 71 are synchronised by the studio synchronisation signal applied to the terminal 83.

Furthermore, the picture store 51 delivers an identification signal through the line 84 to the position computer 71.

it is then possible, with the aid of the position computer 71, to so control the intermediate stores 61 and 62 in accordance with the input data referred to above that a displacement of the picture section is possible in the intermediate store 61 from film frame to film frame and in the intermediate store 62 from television field to television field. In that way, a displacement is achieved without any jerky movement.

Various possibilities with the method in accordance with the invention for the optimally rapid displacement of film frame sections will now be described in detail with the aid of the various readout positions of the intermediately stored video signals illustrated in Fig. 9. In Figs. 9a to 9e, the respective film frame to be scanned or set up on the sensors is illustrated as an inclined hatched rectangle, the portion of the film frame section stored as a video signal in the intermediate store 61 is illustrated as a transversely hatched rectangle and the portion of the film section stored in the intermediate store 62 is illustrated as a white rectangle.

A read-out position with a section in the centre of a film frame for reproduction on the image screen is illustrated in Fig. 9a. If, for example, a slight displacement of the film frame section must then take place to the left or the right within the shortest time, then only the intermediate store 62 need receive the appropriate read-out position, that is to say, the white rectangle is displaced to the left or to the right within the transversely hatched rectangle. Only then does the displacement of the read-out position from the intermediate store 61 take place by the same amount so that the reproduced film section (white rectangle) is once again located in the centre of the read-out position from the intermediate store 61 (see Fig. 9b or 9c). That has the advantage that a desired change in position towards both sides can be carried out optimally rapidly.

On the other hand, if a considerable displacement of the film frame section must take place, then the read-out position from the intermediate store 61 must first of all be displaced as far as possible towards the desired side (see Fig. 9d) and thereafter the read-out position from the intermediate store 62 corresponding to the desired maximal displacement up to the end of the read-out position from the intermediate store 61. If this displacement has not yet been reached, then a further displacement of the read-out position from the intermediate store 61 and then from the intermediate store 62 must take place in the same direction until the desired film frame section is reached (see Fig. 9a). These further displacements take place in the intermediate store 61 for each film frame and in the intermediate store 62 for each television field.

Thus, an optimal use of the displacement possibilities is guaranteed with this method in the shortest time.

By expanding the video signals to a greater extent before the picture storage, particularly at least by the fact 1.5 than after the picture storage better resolution can be achieved.

As a further advantage, it can be appreciated that the selectable displacement of the read-out position is carried out after the picture storage of each television field in steps substantially equal in length so that, a quasi linear displacement of the respective film frame section is possible independently of the film speed and the television standard.

Claims (26)

1. A method for the television scanning of films of the so-called Cinemascope format, in which the frames are recorded compressed in the horizontal direction by the factor of 2, with the aid of line or area sensors on which the entire width of the film frame is formed, characterised in that, in order to prevent strips devoid of picture information at the upper and/or lower edges of the viewing screen during the television reproduction of the film, the video signal is expanded by an appropriate pulsing of storage means and the beginning of the read-out operation is displaced selectively, and the end of the read-out operation is also automatically displaced selectively therewith corresponding to the television standard.

2. A method according to claim 1, characterised in that, the selectable displacement of the read-out beginning is carried out by a manual setting of an adjustment member.

3. A method according to claim 1 and 2, characterised in that, the selectable displacement of the read-out beginning is pre-programmable by the manual setting of the adjustment member.

4. A method according to claim 1 to 3, characterised in that, beginning and end of the read-out operation are each represented by a perpendicular line on a viewing screen reproducing the entire film frame.

5. A method according to claim 1, characterised in that, the storage means are the line or area sensors (1) which are read-out at a pulse frequency reduced by an expansion factor (Ke) whereas the picture memory (4) storing the video signals of a film frame is controlled during the introduction at the normal pulse frequency corresponding to the television standard.

6. A method according to claim 1, characterised in that, the video signals delivered by the sensors are digitalised and then expanded by means of a correspondingly pulsed intermediate memory (41 or 52 or 61, 62) the read-out pulse frequency of which is lower than the read-in pulse frequency by the expansion factor (Ke).

7. A method according to claim 6, characterised in that, the expansion of the digital video signal is carried out before the picture storage of each scanned film frame.

8. A method according to claim 6, characterised in that, the expansion of the digital video signal is carried out after the picture storage of each scanned film frame.

9. A method according to claim 8, characterised in that, the beginning of the read-out operation from the picture memory (51) is set in respect of, a frame, that the read-out data are introduced into an intermediate memory (52) and are read-out at a pulse frequency (f x 1 /we) reduced by the expansion factor (uke).

10. A method according to claim 8, characterised in that, the beginning of the readout operation from the picture store is brought forward by one line, that the read-out data are introduced into a line memory (57) and are read-out at a pulse frequency (f X 1 /Ke) reduced by the expansion factor (Ke)

11. A method according to claim 6, characterised in that, the expansion of the digital video signal is carried out either before or after the picture storage of each scanned film frame, according to the type of operation.

1 2. A method according to claim 6, 7 and 8, characterised in that, the video signals coming from the line sensors are transmitted before the digitalising through low pass circuits (28, 31, 33) the band width of which is increased by the expansion factor (Ke) with respect to that at standard film scanning.

1 3. A method according to claim 8 and 9, characterised in that, to save storage capacity in the picture memory, the video signal read out of the intermediate memory (52) is interpolated in a picture element manner such that, between each two picture elements delivered by the intermediate memory, a third is inserted derived from two picture elements.

14. A method according to claim 13, characterised in that, the video signal interpolated in a picture element manner is interlaced line by line with each other in such a manner that interpolated picture elements are never adjacent in the horizontal and vertical direction.

1 5. A method according to claim 8, 9 and 13, in which, a pre-distortion correcting with the factor 1.1 8 has already been carried out, characterised in that, ony each third picture element is interpolated to save storage capacity in the picture store and to reduced the expansion factor.

1 6. A method according to any one of the preceding claims characterised in that, the video signals delivered by the sensors are digitalised, are then read into a correspondingly pulsed picture store (65) receiving the full Cinemascope film frame and are read out once again at a pulse frequency (f. 1 /Ke) reduced by the expansion factor (Ke) after displacement of the beginning of the read out.

1 7. A method according to any one of the preceding claims, characterised in that, the video signals delivered by the sensors and digitalised are expanded before and after the picture storage of each scanned film frame.

1 8. A method according to claim 17, characterised in that, the expansion of the video signals is greater before the picture storage than after the picture storage.

1 9. A method according to claim 1 7 and 18 characterised in that, the digitalised video signals are expanded in a first intermediate store (61) before the picture store (51) by at least the factor 1.5 and are expanded in a second intermediate store (62) after the picture store (51) by a remaining factor for producing the total expansion of the film frame.

20. A method according to claim 17, characterised in that the selectable displacement of the read-out position of the intermediately stored video signals is carried out before the picture storage in multiple picture element steps and is carried out after the picture storage in picture element steps.

21. A method according to claim 20, characterised in that, the selectable displacement of the read-out position of the intermediately stored video signals is carried out in a film frame manner before the picture storage and is carried out in a television field manner after the picture storage in steps of substantially the same length.

22. A method according to claim 19, 20 or 21, characterised in that, during an insignificant displacement of the picture section, the displacement of the read-out position of the second intermediate store (62) is first carried out and that thereafter the read-out position of the first intermediate store (61) is displaced by the same amount.

23. A method according to claim 19, 20 or 21 characterised in that, with large displacements of the picture section, the read-out position of the first intermediate store (61) is first of all displaced at least once and thereafter that of the second intermediate store (62) is displaced at least once.

24. A method according to claim 17, 1 8 or 1 9 in which the selectable displacement of the read-out position is carried out with the aid of an adjustment member, characterised in that, after establishing the picture section to be presented the data delivered by the adjustment member (72) are converted in a microcomputer (71) into addresses for the control of the two intermediate stores (61, 62).

25. A method substantially as hereinbefore described with reference to the accompanying drawings.

26. Apparatus for carrying out the method according to any one of the preceding claims.