EP0162486A2
Expired / Lapsed
EP
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Improvements in telecine machines
Assignee: British Broadcasting Corp
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Filing: 1983-03-29
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Granted: —
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Expires: 2003-03-29
Abstract
Abstract Telecine apparatus preferably of the line array type has the line scan rate controlled in response to a tachometer sensing the instantaneous film speed to overcome problems caused by film speed variations. The output signal is compensated in inverse relation to the scan period to compensate for consequent variations in the integration timeforthe array. For very slow film speeds the actual scan rate is increased from the required scan rate by a factor of a power of two and unwanted scans (dummy scans) are ignored. For very fast film speeds the actual scan rate is decreased from the theoretically required scan rate by a factor m, likewise a power of two, and a full picture formed from lines from the lastest m/2 fields, or by repeating or interpolating lines in the latest field only. To find a shot change at low film speeds the output picture has two parts, the junction between them being defined by a particular line scan, and the two parts being derived from two adjacent film frames. When the film is stopped, one part of the picture is the normal interlaced output and another part formed from a line direct from the linear array to enable proper functioning of the array to be confirmed.
Inventors
- 👤 Ian Childs
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 21:56
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/36; H04N3/38; H04N9/00; H04N9/11
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
141 words
Telecine apparatus comprising a film transport mechanism, scan means for line-by-line scanning of the film to provide a raster-scanned electrical signal representative of the film image, scan control means having an output connected to the scan means to control the periodicity of the scan whereby the line scan rate can be materially varied from the nominal rate corresponding to normal viewing of the film, and signal processing circuitry connected to the output of the scan means, characterised in that the scan control means includes means for detecting when the required line scan rate is less than a predetermined fraction of the said nominal rate, and in response thereto causes the scan means to increase the line scan rate by a factor m, and in that the signal processing circuitry selects only one out of each m generated lines for subsequent processing.
Claim 2
Dependent Claim
141 words
Telecine apparatus comprising a film transport mechanism, scan means for line-by-line scanning of the film to provide a raster-scanned electrical signal representative of the film image, scan control means having an output connected to the scan means to control the periodicity of the scan whereby the line scan rate can be materially varied from the nominal rate corresponding to normal viewing of the film, and signal processing circuitry connected to the output of the scan means, characterised in that the scan control means includes means for detecting when the required line scan rate is less than a predetermined fraction of the said nominal rate, and in response thereto causes the scan means to increase the line scan rate by a factor m, and in that the signal processing circuitry selects only one out of each m generated lines for subsequent processing.
Claim 3
Dependent Claim
33 words
Apparatus according to claim 1, in which each line selected by the signal processing means is arranged to be of substantially constant duration independent of changes in the said required line scan rate.
Claim 4
Dependent Claim
17 words
Apparatus according to claim 1 or 2, in which the factor m is a power of two.
Claim 5
Dependent Claim
53 words
Apparatus according to claim 1, 2 or 3, in which the scan control means includes means for detecting when the required line scan rate exceeds a predetermined maximum rate, and in response thereto causes the scan means to decrease the scan rate by a factor m dependent upon the required line scan rate.
Claim 6
Dependent Claim
122 words
Telecine apparatus comprising a film transport mechanism, scan means for line-by-line scanning of the film to provide a raster-scanned electrical signal representative of the film image, scan control means having an output connected to the scan means to control the periodicity of the scan whereby the line scan rate can be materially varied from the nominal rate corresponding to normal viewing of the film, and signal processing circuitry connected to the output of the scan means, characterised in that the scan control means includes means for detecting when the required line scan rate exceeds a predetermined maximum rate, and in response thereto causes the scan means to decrease the scan rate by a factor m dependent upon the required line scan rate.
Claim 7
Dependent Claim
122 words
Telecine apparatus comprising a film transport mechanism, scan means for line-by-line scanning of the film to provide a raster-scanned electrical signal representative of the film image, scan control means having an output connected to the scan means to control the periodicity of the scan whereby the line scan rate can be materially varied from the nominal rate corresponding to normal viewing of the film, and signal processing circuitry connected to the output of the scan means, characterised in that the scan control means includes means for detecting when the required line scan rate exceeds a predetermined maximum rate, and in response thereto causes the scan means to decrease the scan rate by a factor m dependent upon the required line scan rate.
Claim 8
Dependent Claim
26 words
Apparatus according to claim 4 or 5, in which the output lines of each field are derived from m/2 different film frames in a cyclical sequence.
Claim 9
Dependent Claim
37 words
Apparatus according to claim 4, 5 or 6,in which the output lines of each field are derived from one film frame only and the signal processing circuitry is operative to generate m lines from each scanned line.
Claim 10
Dependent Claim
20 words
Apparatus according to claim 7, in which the output lines are derived by repeating lines from the said film frame.
Claim 11
Dependent Claim
23 words
Apparatus according to claim 7 or 8, in which the output lines are derived by interpolating from lines of the said film frame.
Claim 12
Dependent Claim
17 words
Apparatus according to any of claims 4 to 9, in which m is a power of two.
Claim 13
Dependent Claim
106 words
Apparatus according to any preceding claim including signal processing circuitry connected to the output of the scan means and comprising a digital store capable of storing at least one field, and characterised in that at least when the film is not moving above a predetermined low value below its nominal speed the signal processing circuitry is adapted to select for one part of the image lines derived from one film frame and for another part of the image lines derived from an adjacent film frame, the junction between the two parts being defined by the line being scanned by the scan means at a particular instant.
Claim 14
Dependent Claim
21 words
Apparatus according to claim 11, in which the junction between the two parts is defined by the lines being instantaneously scanned.
Claim 15
Dependent Claim
29 words
Apparatus according to claim 11 or 12, in which the junction between the two parts is defined by the line being scanned at the beginning of each television field.
Claim 16
Dependent Claim
20 words
Apparatus according to claim 11, 12 or 13, in which a blanked line or lines is formed at the join.
Claim 17
Dependent Claim
90 words
Apparatus according to any preceding claim, including signal processing circuitry connected to the output of the scan means and comprising a sequential-to-interlaced converter for converting the video signal to interlaced form, and characterised in that at least in one mode of operation of the apparatus the signal processing circuitry selects for application to a review output of the apparatus the interlaced output of the converter for lines forming one part of the picture and the input line to the converter which is repeated to form another part of the picture.
References Cited (Backward Citations)
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