GB2167265A

GB2167265A - Television film scanner

Info

Publication number: GB2167265A
Application number: GB08527014A
Authority: GB
Inventors: Dieter Poetsch
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1984-11-17
Filing date: 1985-11-01
Publication date: 1986-05-21
Also published as: DE3442064A1; GB8527014D0; GB2167265B

Abstract

In a television film scanner the visibility of a bonded film frame joint is suppressed by repeating the video signal corresponding to the first undisturbed frame following the bonded joint. The video signal derived by photoelectrically scanning a film 1 is passed via digital image storage devices 12 and 30 to an output 13. Device 30 delays the video output by at least one frame period. When a bonded film frame joint is sensed 19 a shift register 22 is arranged to cause a switch 31 to output the video signal from storage device 12 while the frame disturbed by the joint is stored in device 30. Following this, the switch 31 is switched back to the output of device 30 so that the same frame is transmitted at least twice. <IMAGE>

Description

SPECIFICATION Television film scanner Prior art The invention is based on a television film scanner according to the generic type of the main claim according to patent application P 33 18 253.1.

As already described in main application P 33 18 253.1 bonded film joints cause visible interference when using reversal or negative films, particularly in the case of the 16-mm format, this interference being visible before the joint at the lower edge of the picture and after the joint at the upper edge of the picture in the reproduced picture. To avoid these and other disturbances, it had been proposed in the main application to block the recording of the video signal in the image storage device for the scan period of at least one film frame and to read the video signal of the previously recorded film frame repeatedly from the image storage device for this period.

It has now been found that if rapid movements occur in the scene before the function of frame repetition from the image storage device is switched on, a disturbance resulting from the freezing of the sequence of motion becomes detectable since the brain is already aware of the picture content.

For this reason, the present invention is based on the objective of improving the film scanner specified in the main application in such a manner that if bonded joints are covered at points of scene changes, the disturbance mentioned is avoided.

The achievement of this objective was based on the finding that when a new content appears in the picture which is different from the previous content, perception of the image in the brain requires a certain period of time for recognising this new picture content. In the solution according to the invention, therefore, it is not the last undisturbed picture before but advantageously the first undisturbed picture after the bonded joint which is repeated when bonded joints are covered.

Drawing Illustrative embodiments of the invention are explained in greater detail in the description which follows and are shown in the drawing, in which: Figure 1 shows a block diagram of an illustrative embodiment of the device according to the invention of a television film scanner, Figure 2 shows another block diagram of another illustrative embodiment.

In the Figures, only those parts are shown which are necessary for explaining the invention. In Fig. 1, the film 1 to be scanned is transported in the direction of the arrow through an already known scanning device consisting of film gate 2, illuminating device 3, imaging optics 4 and colour separation optics 6 at which opto-electric image sensors 7, 8, 9 are arranged. The outputs of the opto-electric image sensors 7 to 9 are connected via a video processor 11, in which the video signals are processed and digitised in familiar manner, to a digital image storage device 12. At the output of the image storage device 12, a video output signal suitable for studio use is available by clocking the readout of the image storage device 12 via the clock input 14 at the studio clock rate.The output of the storage device 12 is connected to at least one further digital image storage device 30 in which the video signal suitable for studio use is delayed by at least one further frame period.

This video signal, delayed by at least two frame periods, is connected to one input of a change-over switch 31 at the other input of which the output signal of the storage device 12 is present. Thus, a video signal delayed by at least two frame periods with respect to the input signal of the storage device 12 can be picked up at the output 13 in the position of the change-over switch 31 as drawn.

To detect bonded film frame joints, a sensor 19 is provided in front of the scanning device. This sensor 19 can be, for example, an infrared light barrier, known in itself, or a device responding to capacitants detuning in a tuned circuit. The signal generated by the sensor 19 is then fed to a switching pulse shaper circuit 21 in which a corresponding switching pulse is derived. This switching pulse is input into a shift register 22. The shift register 22 is controlled as a function of the speed of rotation of the sprocket wheel 16, that is to say of the feed rate of the film 1, and of the imaging optics 4 which depend on the film format used.

At the output of the shift register 22, a switching pulse, which actuates the changeover switch, can then be picked up when the bonded film joint appears in the film gate 2.

Due to the change-over switch 31 switching over to the output of the storage device 12, the video signal of the disturbed frame stored in the storage device 30 is suppressed and, instead, the video signal of the undisturbed frame stored in the storage device 12 is transferred to the output 13. Following this, the change-over switch 31 is switched back to the output of the storage device 30 so that the video signal of this frame, already transmitted, is again present at the output 13, that is to say is transmitted twice.

In Fig. 2, another illustrative embodiment of a device for covering bonded joints is shown.

The parts already occurring in Fig. 1 of the television film scanner are here provided with the same reference symbols. Instead of the bonded joint detection device 19, 21 and 22 according to Fig. 1, a storage device 31 is provided in Fig. 2, which storage device can be manually controlled via several inputs 24 or by an automatic circuit for detecting the scene change 27 via an input 26. The bonded joints found before the transmission are in each case manually entered in accordance with the film frame numbers for storage via inputs 24 into storage device 23. But it is also possible to use the automatic circuit 27 to provide control as a function of the output signal of the video processor 11. By this means, the scene change is automatically detected from the image content (video signal) and the change-over switch 31 is actuated via the storage device 23 since in the case of reversal films, a bonded joint occurs in most cases at a scene change.

Claims

1. Television film scanner comprising optoelectric sensors for converting the scanned film frames into video signals which are recorded in an image storage device and are read out of the latter in accordance with the television standard, in accordance with Patent Appiication P 33 18 253.1, in which arrangement at least one further image storage device (30) is provided in series with the image storage device (12), which causes the video signais to be transmitted delayed by at least two film frames in each case, characterised in that a change-over switch (31), the two inputs of which are connected to the outputs of the image storage devices (12, 30), is provided at the output (13) of which the delayed video signals can be picked up, that when a bonded joint occurs, the output (13) is separated from the output of the further image storage device (30) and connected to the output of the image storage device (12), and that the change-over switch (31) is switched back into its original position after the signal delay of the further storage device or storage devices (30) has elapsed, so that this first undisturbed film frame following the bonded joint is repeatedly read out of the image storage devices.

2. Television film scanner according to Claim 1, characterised in that the change-over switch (31) is actuated as a function of a bonded joint detection device (19) arranged closely in front of the film gate (2).

3. Television film scanner according to Claim 1, characterised in that the change-over switch (31) is actuated by a frame number memory (23), particularly as a function of an automatic device for detecting scene changes (27).

4. A television film scanner substantially as herein described with reference to Fig. 1 or Fig. 2 of the accompanying drawing.