EP0574239A1
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EP
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Method and apparatus for reading photographically recorded digital audio signals
Assignee: Sony Electronics Inc
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Filing: 1993-06-09
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Granted: —
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Expires: 2013-06-09
Abstract
Abstract A method and apparatus for reading digital audio signals photographically recorded on a medium (such as motion picture film). If the medium has multiple, spatially separated digital and analog audio soundtracks, a photosensitive detector array is employed for each of the digital audio soundtrack areas, and a separate analog soundtrack read head is employed. Preferably, digital error code is recorded in a digital soundtrack area of the medium (with digital audio bits), and error detection and correction are performed on the recorded digital audio bits read from the medium. Preferably, the apparatus includes switching circuitry for substituting a corresponding analog audio signal for one or more corrupted digital soundtrack channels, when such digital soundtrack channels have an error rate which exceeds a selected threshold. Also preferably, the apparatus reads recorded digital audio information by projecting a laser beam (having a near infrared wavelength) on a row of a digital soundtrack area of a motion picture film, to modulate the beam as it passes through the row. The radiation transmitted through each digital soundtrack bit area is projected onto a spot in the detector plane that is substantially larger than the dimension of each individual detector which receives the spot. As the film translates continuously relative to the radiation source so that the projection of the spot translates relative to each receiving detector, the output of each receiving detector is integrated over the period during which a portion of the spot is projected thereon.
Inventors
- 👤 Michael Kohut
- 👤 Dana Wood
- 👤 Paul Wood
- 👤 Jeff Taylor
- 👤 Leroy Reese
- 👤 Aram Tanielian
- 👤 Jaye M. Waas
- 👤 Mark Waring
- 👤 George Carlsen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 15:08
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/002; G11B7/003; G11B7/0032; G03; G03B; G03B31/00; G03B31/02
Claims Analysis
Total Claims: 53
Claim 1
Independent Claim
129 words
An apparatus for reading digital audio bits that have been recorded photographically in bit areas of a photosensitive medium, including: a means for continuously translating the medium along a column axis; a linear array of radiation detectors fixedly mounted in a detector plane, each of the detectors having a length L along a first axis and a width W along a second axis; and radiation projection means for projecting a beam of radiation through a row of the bit areas onto a row of spots in the detector plane while the medium translates along the column axis, wherein the row of spots extends along the second axis, each of the spots has a length S along the first axis, and the length S is greater than the length L.
Claim 2
Dependent Claim
58 words
The apparatus of claim 1, wherein the beam of radiation is projected through the bit areas for a period T, wherein the linear array of radiation detectors includes means for generating an output signal for each of the detectors, and wherein each said output signal is indicative of an intensity of incident radiation integrated over the period T.
Claim 3
Dependent Claim
47 words
The apparatus of claim 1, wherein the beam of radiation is a beam of coherent radiation, and wherein the radiation projection means includes a means for generating the beam of coherent radiation and directing said beam along a beam path through said row of the bit areas.
Claim 4
Dependent Claim
22 words
The apparatus of claim 3, wherein the detectors are CCD detectors, and the beam of coherent radiation has a near infrared wavelength.
Claim 5
Dependent Claim
33 words
The apparatus of claim 1, wherein the bit areas are located within three elongated soundtrack regions of the medium, and wherein the elongated soundtrack regions are oriented substantially parallel to the column axis.
Claim 6
Dependent Claim
68 words
The apparatus of claim 5, also including: a second linear array of radiation detectors; and a third linear array of radiation detectors; wherein the radiation projection means includes a means for projecting a beam of radiation through a row of each of the elongated soundtrack regions and onto each of the linear array of detectors, the second linear array of detectors, and the third linear array of detectors.
Claim 7
Dependent Claim
74 words
The apparatus of claim 6, wherein a first one of the elongated soundtrack regions has a contrast ratio and a second one of the elongated soundtrack regions has a second contrast ratio, wherein the second contrast ratio is different than the contrast ratio, wherein the linear array of detectors has an optimal sensitivity to the contrast ratio, and wherein the second linear array of detectors has an optimal sensitivity to the second contrast ratio.
Claim 8
Dependent Claim
138 words
The apparatus of claim 5, wherein the medium is a motion picture film through which a first column of sprocket holes and a second column of sprocket holes extend, wherein the motion picture film has a picture area between the first column of sprocket holes and the second column of sprocket holes, and wherein a first one of the elongated soundtrack regions extends substantially parallel to the first axis between the picture area and the first column of sprocket holes, a second one of the elongated soundtrack regions extends substantially parallel to the first axis between the picture area and the second column of sprocket holes, and a third one of the elongated soundtrack regions extends substantially parallel to the first axis between the second one of the elongated soundtrack regions and the second column of sprocket holes.
Claim 9
Dependent Claim
24 words
The apparatus of claim 1, wherein each of the spots has a width equal to at least an integral multiple of the width W.
Claim 10
Dependent Claim
36 words
The apparatus of claim 9, wherein each of the spots has a width equal to at least 3W, and wherein each of the spots is projected on three adjacent detectors in the linear array of detectors.
Claim 11
Dependent Claim
56 words
The apparatus of claim 1, wherein the bit areas include error code bits and digital audio bits, and also including: a digital optical playback processor for receiving a digital output signal from the array of radiation detectors, wherein the digital output signal is indicative of error code bits and digital audio bits read from the medium.
Claim 12
Dependent Claim
42 words
The apparatus of claim 11, wherein the digital optical playback processor includes an error detection and correction means, for performing an error detection operation on the digital output signal and generating an error corrected digital output signal from the digital output signal.
Claim 13
Dependent Claim
72 words
The apparatus of claim 12, wherein the digital optical playback processor also includes: means for generating a first analog signal from the error corrected digital output signal; and an automatic backup switching means, which receives the first analog signal, an externally generated analog soundtrack signal, and a control signal, and generates an output signal consisting of selected portions of the first analog signal concatenated with selected portions of the analog soundtrack signal.
Claim 14
Dependent Claim
59 words
The apparatus of claim 13, wherein the error detection and correction means processes blocks of the digital output signal, and wherein the error detection and correction means includes a means for generating and supplying the control signal to the automatic backup switching means upon determining that one of the blocks has an error rate which exceeds a preset value.
Claim 15
Dependent Claim
46 words
The apparatus of claim 11, wherein the digital output signal includes multiple channels of digital audio data, and wherein the digital optical playback processor also includes: a mixing means for generating mixed channel data by mixing selected ones of the multiple channels of digital audio data.
Claim 16
Dependent Claim
26 words
The apparatus of claim 11, wherein the mixing means receives eight channels of digital audio data and generates therefrom six mixed channels of digital audio data.
Claim 17
Dependent Claim
67 words
The apparatus of claim 16, wherein the eight channels of digital data include a Sub Woofer channel, a Right/Center channel, a Surround Left channel, a Right channel, a Center channel, a Left channel, a Surround Right channel, and a Left/Center channel, and the mixed channels of digital data include a mixed Left channel, a mixed Center channel, a mixed Right channel, and a mixed Sub Woofer channel.
Claim 18
Dependent Claim
89 words
The apparatus of claim 11, wherein the mixing means receives eight channels of digital audio data and generates therefrom four mixed channels of digital audio data, wherein the eight channels of digital data include a Sub Woofer channel, a Right/Center channel, a Surround Left channel, a Right channel, a Center channel, a Left channel, a Surround Right channel, and a Left/Center channel, and wherein the mixed channels of digital data include a mixed Left channel, a mixed Center channel, a mixed Right channel, and a mixed monophonic Surround channel.
Claim 19
Dependent Claim
80 words
The apparatus of claim 12, wherein the error detection and correction means processes blocks of the digital output signal, wherein the error detection and correction means includes a means for generating an error rate signal for each of the blocks, and wherein the digital optical playback processor includes: a means for integrating the error rate signal to generate a filter control signal; and low-pass-filter means for filtering the error corrected digital output signal in response to the filter control signal.
Claim 20
Dependent Claim
25 words
The apparatus of claim 19, wherein the low-pass-filter filters the error corrected digital output signal at a slew rate determined by the filter control signal.
Claim 21
Dependent Claim
114 words
A digital optical playback processor, including: means for receiving a digital playback signal from a digital optical soundtrack read head, and an analog playback signal from an analog optical soundtrack read head, wherein the digital playback signal is indicative of digital audio bits read from bit areas of a photosensitive medium; digital-to-analog conversion means for generating a first analog signal from the digital playback signal; and an automatic backup switching means, for receiving the first analog signal, the analog playback signal, and a control signal, and generating an output signal consisting of selected portions of the first analog signal concatenated with selected portions of the analog playback signal in response to the control signal.
Claim 22
Dependent Claim
73 words
The processor of claim 21, wherein the digital playback signal is also indicative of error code bits read from bit areas of the photosensitive medium, also including: error detection and correction means for performing an error detection operation on the digital playback signal and generating an error corrected digital playback signal from the digital playback signal, wherein the digital-to-analog conversion means generates the first analog signal from the error corrected digital playback signal.
Claim 23
Dependent Claim
59 words
The processor of claim 22, wherein the error detection and correction means processes blocks of the digital playback signal, and wherein the error detection and correction means includes a means for generating and supplying the control signal to the automatic backup switching means upon determining that one of the blocks has an error rate which exceeds a preset value.
Claim 24
Dependent Claim
58 words
The processor of claim 21, also including: a control means for generating a control signal for deactivating a radiation source within the digital optical soundtrack read head, in response to a feedback signal from the digital optical soundtrack read head, wherein said feedback signal is indicative of whether film is translating through the digital optical soundtrack read head.
Claim 25
Dependent Claim
59 words
The processor of claim 21, wherein the digital playback signal includes multiple channels of digital audio data, also including: a mixing means for generating a mixed digital playback signal indicative of selectively mixed ones of the multiple channels of digital audio data, and wherein the digital-to-analog conversion means generates the first analog signal from the mixed digital playback signal.
Claim 26
Dependent Claim
33 words
The processor of claim 25, wherein the mixing means receives eight channels of digital audio data, and wherein the mixed digital playback signal is indicative of six mixed channels of digital audio data.
Claim 27
Dependent Claim
67 words
The processor of claim 25, wherein the eight channels of digital data include a Sub Woofer channel, a Right/Center channel, a Surround Left channel, a Right channel, a Center channel, a Left channel, a Surround Right channel, and a Left/Center channel, and the mixed channels of digital data include a mixed Left channel, a mixed Center channel, a mixed Right channel, and a mixed Sub Woofer channel.
Claim 28
Dependent Claim
96 words
The processor of claim 25, wherein the mixing means receives eight channels of digital audio data, and wherein the mixed digital playback signal is indicative of four mixed channels of digital audio data, wherein the eight channels of digital data include a Sub Woofer channel, a Right/Center channel, a Surround Left channel, a Right channel, a Center channel, a Left channel, a Surround Right channel, and a Left/Center channel, and wherein the mixed channels of digital data include a mixed Left channel, a mixed Center channel, a mixed Right channel, and a mixed monophonic Surround channel.
Claim 29
Dependent Claim
75 words
The processor of claim 22, wherein the error detection and correction means processes blocks of the digital playback signal, wherein the error detection and correction means includes a means for generating an error rate signal for each of the blocks, and also including: a means for integrating the error rate signal to generate a filter control signal; and low-pass-filter means for filtering the error corrected digital output signal in response to the filter control signal.
Claim 30
Dependent Claim
25 words
The processor of claim 29, wherein the low-pass-filter filters the error corrected digital playback signal at a slew rate determined by the filter control signal.
Claim 31
Dependent Claim
76 words
The processor of claim 21, also including: means for receiving a second digital playback signal from a second digital optical soundtrack read head; and switching means for selecting a desired one of the digital playback signal and the second digital playback signal in response to an externally generated changeover control signal, wherein the digital-to-analog conversion means generates the first analog signal from said desired one of the digital playback signal and the second digital playback signal.
Claim 32
Independent Claim
192 words
An apparatus for reading rows of digital audio bits that have been recorded photographically in bit areas of a motion picture film having a longitudinal axis, including: a film transport means for continuously translating the film along a path parallel to the longitudinal axis; a first array of radiation detectors mounted in a detector plane, wherein each of the detectors in the first array has a length L along a first axis and a width W along a second axis; first laser means for directing a first laser beam through a first region of the film at a first location along the path, wherein the first region is oriented substantially perpendicularly to the longitudinal axis; and first lens means for receiving the first laser beam after it has propagated through the first region, converting the first laser beam into a first expanded beam, and projecting the first expanded beam onto a row of spots in the detector plane, wherein the row of spots extends along the second axis, wherein each of the spots has a length S along the first axis, and wherein the length S is greater than the length L.
Claim 33
Dependent Claim
28 words
The apparatus of claim 32, wherein each of the spots has a width, along the second axis, equal to at least an integral multiple of the width W.
Claim 34
Dependent Claim
39 words
The apparatus of claim 33, wherein each of the spots has a width equal to at least 3W, and wherein each of the spots is projected on a set of three adjacent detectors in the first array of detectors.
Claim 35
Dependent Claim
58 words
The apparatus of claim 33, wherein each of the spots has a width substantially equal to 42 microns, wherein S is substantially equal to 42 microns, and wherein each of the three adjacent detectors has a length substantially equal to 14 microns along the first axis and a width substantially equal to 14 microns along the second axis.
Claim 36
Dependent Claim
21 words
The apparatus of claim 32, wherein the detectors are CCD detectors, and the first laser beam has a near infrared wavelength.
Claim 37
Dependent Claim
37 words
The apparatus of claim 32, wherein the bit areas are located within at least two spatially separated elongated soundtrack regions of the film, and wherein the elongated soundtrack regions are oriented substantially parallel to the longitudinal axis.
Claim 38
Dependent Claim
185 words
The apparatus of claim 37, wherein the first region intersects a first one of the elongated soundtrack regions, and also including: a second array of radiation detectors mounted in a second detector plane, wherein each of the detectors in the second array has a length M along a third axis and a width X along a fourth axis; a second laser means for directing a second laser beam through a second region of the film, wherein the second region is oriented substantially perpendicularly to the longitudinal axis and intersects a second one of the elongated soundtrack regions; and a second lens means for receiving the second laser beam after it has propagated through the second region, converting the second laser beam into a second expanded beam, and projecting at least a portion of the second expanded beam onto a second row of spots in the second detector plane, wherein the second row of spots extends along the fourth axis, each of the spots in the second row has a length T along the third axis, and the length T is greater than the length M.
Claim 39
Dependent Claim
106 words
The apparatus of claim 38, also including: a third array of radiation detectors mounted in a third detector plane, wherein each of the detectors in the third array has a length N along a fifth axis and a width Y along a sixth axis; and wherein the second lens means projects a portion of the second expanded beam onto a third row of spots in the third detector plane, wherein the third row of spots extends along the sixth axis, each of the spots in the third row has a length U along the fifth axis, and the length U is greater than the length N.
Claim 40
Dependent Claim
76 words
The apparatus of claim 38, wherein the first one of the elongated soundtrack regions has a first contrast ratio and the second one of the elongated soundtrack regions has a second contrast ratio, wherein the second contrast ratio is different than the first contrast ratio, wherein the first array of detectors has an optimal sensitivity to the first contrast ratio, and wherein the second array of detectors has an optimal sensitivity to the second contrast ratio.
Claim 41
Dependent Claim
55 words
The apparatus of claim 32, wherein the means for continuously translating the film includes a member which moves in response to translation of the film through the apparatus, and also including: a film motion detector which monitors movement of the member to generate a feedback signal indicative of whether film is translating through the apparatus.
Claim 42
Dependent Claim
45 words
The apparatus of claim 41, also including a digital optical playback processor means for receiving the feedback signal, and control signal means within the digital optical playback processor for generating a control signal for deactivating the first laser means in response to the feedback signal.
Claim 43
Dependent Claim
25 words
The apparatus of claim 41, wherein the member is a sprocket wheel which engages the film and rotates in response to translation of the film.
Claim 44
Dependent Claim
29 words
The apparatus of claim 43, wherein the sprocket wheel is marked with strobe marks, and the film motion detector is positioned to detect radiation reflected from said strobe marks.
Claim 45
Dependent Claim
32 words
The apparatus of claim 32, also including: a knife edge vacuum means, mounted at a second location along a path, for cleaning the film as the film translates past the second location.
Claim 46
Dependent Claim
38 words
The apparatus of claim 45, wherein the knife edge vacuum means is a passive assembly that is actuated by forces mechanically exerted thereon by the film transport means at times when the film is translating along the path.
Claim 47
Independent Claim
124 words
An apparatus for reading analog and digital soundtracks that have been recorded photographically on a motion picture film having a longitudinal axis, including: a film transport means for continuously translating the film along a path from a feed reel to a takeup reel; a digital optical soundtrack read head, positioned at a first location along the path, for generating a digital playback signal indicative of digital audio bits read from bit areas of the motion picture film; an analog optical soundtrack read head, positioned at a second location along the path between the first location and the takeup reel, for generating an analog playback signal; and a digital optical playback processor which receives and processes the digital playback signal and the analog playback signal.
Claim 48
Dependent Claim
56 words
The apparatus of claim 47, wherein the digital optical playback processor includes: a digital signal delay means for delaying the digital playback signal by a selected time period; digital-to-analog conversion means for receiving a delayed digital playback signal from the digital signal delay means, and generating a first analog signal from the delayed digital playback signal.
Claim 49
Dependent Claim
61 words
The apparatus of claim 48, wherein the digital optical playback processor also includes: an automatic backup switching means, for receiving the first analog signal, the analog playback signal, and a control signal, and generating an output signal consisting of selected portions of the first analog signal concatenated with selected portions of the analog playback signal in response to the control signal.
Claim 50
Independent Claim
91 words
A method for reading photographically recorded digital audio bits from bit areas of a photosensitive medium, including the steps of: continuously translating the medium along a column axis; and projecting a beam of radiation through a row of the bit areas onto a row of spots on an array of radiation detectors in a detector plane while the medium translates along the column axis, wherein each of the detectors has a length L, wherein each of the spots has a length S, and wherein S is greater than the length L.
Claim 51
Dependent Claim
59 words
The method of claim 50, wherein the beam of radiation is projected through the bit areas for a period T, and also including the step of: generating an output signal for a first one of the detectors, wherein the output signal is indicative of beam intensity incident at the first one of the detectors integrated over the period T.
Claim 52
Independent Claim
103 words
A method for processing a digital playback signal from a digital optical soundtrack read head, and an analog playback signal from an analog optical soundtrack read head, wherein the digital playback signal is indicative of digital audio bits read from bit areas of a photosensitive medium, including the steps of: generating a first analog signal from the digital playback signal; and receiving the first analog signal, the analog playback signal, and a control signal, and generating an output signal consisting of selected portions of the first analog signal concatenated with selected portions of the analog playback signal in response to the control signal.
Claim 53
Dependent Claim
63 words
The method of claim 52, wherein the digital playback signal is also indicative of error code bits read from bit areas of the photosensitive medium, also including the steps of: performing an error detection operation on the digital playback signal; and performing an error detection operation on the digital playback signal before said first analog signal is generated from the digital playback signal.
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