Patent EP0100811A2 successfully refreshed from Google Patents.
EP0100811A2
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EP
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Apparatus for reproducing various tone and line originals and methods of operation thereof
Assignee: International Business Machines Corp
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Filing: 1983-01-28
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Granted: —
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Expires: 2003-01-28
Abstract
Abstract A document scanner 10 scans a document to be reproduced and the serial output data (PEL's) is provided to a system controller 30 and to an input buffer means 14. The controller 30 provides control signals on line 50 to a print decision multiplexor 48 which can receive inputs on lines 44, 46,54. The input on 54 is selected when a line copy algorithm is to be used to control printing, the input on line 44 when a continuous tone print algorithm is to be used to control printing and the input on line 46 is to be used when a third algorithm is to be used suitable for areas of an original not clearly continuous tone or line tone. The appropriate line 44, 46, 54 is selected in accordance with the sequence of data representing the original. For this purpose gradient logic means 26 is connected by busses 16, 18, 20, 22. 24 to selected storage positions of the buffer means 14 and generates a gradient signal on line 28 for each PEL Similarly look ahead logic means 32 are connected by busses 20', 22', 24' to selected storage positions of the buffer means 14. The look ahead means 32 provide signals on lines 34, 36 indicative of whether any selected storage position respectively hold a white valued or black valued PEL In addition hysteresis counters 40 provide signals on lines 58 thro' 96 indicative of the preceding operational mode and / or preceding PEL values. Latches 104,106.108,110 provide respectively reference signals indicative of a white threshold level, a black threshold level, a threshold level usable for line copy and a datum gradient value. The system controlled 30 is a data processor and is operative to correlate the signals supplied to it and to generate control signals for the multiplexor block 48. In a second apparatus the scanner output is supplied to a discriminator 154 which processes the signal it receives and determines whether a PEL represents line or non-line copy information. The discriminator 154 controls switch 160 via line 156 in accordance with the determination. For line copy the original signal on line 162 is routed to discriminator 166 and for non-line copy the processed signal on line 158 is routed to discriminator 166. Discriminator 166 descriminates between line copy and continuous tone copy and supplies the decisions to discriminator 170. The discriminator 170 forms a map of all the decisions and if the decision for a particular PEL is different from its surrounding PEL's, the decision is changed to match that of its surroundings. The output of discriminator 170 controls switch 180 which routes the original PEL data on line 176 to fixed thresholder 180 for line copy and to thresholder 184 for continuous tone copy.
Inventors
- 👤 Sidney Jared Fox
- 👤 Filip Jay Yeskel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 23:34
CPC Classifications
G; G06; G06V; G06V30/00; G06V30/40; G06V30/41; G06V30/413; H; H04; H04N; H04N1/00; H04N1/40; H04N1/40062; H04N1/403
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
142 words
A method of reproducing an original document represented by a serial stream of digital data with each set of digital data having a PEL value corresponding to the value of a surface characteristic associated with elemental areas of the original document, said method comprising the following steps: a) selecting sets of digital data situated between predetermined white and black threshold levels; b) determining if the sets of digital data have surface characteristics similar to the surface characteristic of elemental areas of the original document contiguous to the elemental area whose surface characteristic is being represented by the sets of digital data; - c) utilizing a first technique to process items of digital data having similar surface characteristics; d) utilizing a second technique to process items of digital data having dissimilar surface characteristics; and e) utilizing an appropriate thresholder to process the data.
Claim 2
Independent Claim
142 words
A method of reproducing an original document represented by a serial stream of digital data with each set of digital data having a PEL value corresponding to the value of a surface characteristic associated with elemental areas of the original document, said method comprising the following steps: a) selecting sets of digital data situated between predetermined white and black threshold levels; b) determining if the sets of digital data have surface characteristics similar to the surface characteristic of elemental areas of the original document contiguous to the elemental area whose surface characteristic is being represented by the sets of digital data; - c) utilizing a first technique to process items of digital data having similar surface characteristics; d) utilizing a second technique to process items of digital data having dissimilar surface characteristics; and e) utilizing an appropriate thresholder to process the data.
Claim 3
Dependent Claim
134 words
Apparatus for reproducing an original document represented by a serial stream of digital data with each set of digital data having a PEL value corresponding to the value of the surface reflectance associated with elemental areas of the original documents comprising: means for selecting sets of digital data situated between a predetermined white and a predetermined black level; means for determining if the sets of digital data have surface characteristics similar to the surface characteristics of contiguous elemental areas of the original documents whose surface characteristics are being represented by the sets of digital data; means including a first technique operable to process items of digital data having similar surface characteristics; means including a second technique operable to process items of digital data having dissimilar surface characteristics; and thresholding means to process the data.
Claim 4
Dependent Claim
134 words
Apparatus for reproducing an original document represented by a serial stream of digital data with each set of digital data having a PEL value corresponding to the value of the surface reflectance associated with elemental areas of the original documents comprising: means for selecting sets of digital data situated between a predetermined white and a predetermined black level; means for determining if the sets of digital data have surface characteristics similar to the surface characteristics of contiguous elemental areas of the original documents whose surface characteristics are being represented by the sets of digital data; means including a first technique operable to process items of digital data having similar surface characteristics; means including a second technique operable to process items of digital data having dissimilar surface characteristics; and thresholding means to process the data.
Claim 5
Dependent Claim
279 words
Apparatus for reproducing an original represented by a serial stream of digital data, each item of data having a PEL value corresponding to the value of a surface characteristic (e.g. reflectance) of the elemental area (PEL) of the original represented by the item of data, said apparatus being capable of operating in more than one mode to produce copies of different or mixed nature (e.g. continuous tone, line or printed) originals and comprising: buffer means for receiving and buffering the serial stream of data; means for comparing the value of each item of data with first and second threshold values and operable to generate contrast signals indicative of whether the PEL value is greater than the first threshold value, between the threshold values, or below the second threshold value; first means effective in operation to cause the apparatus to operate in a first mode according to a first algorithm; second means effective in operation to cause the apparatus to operate in a second mode according to a second algorithm; selection means connected to receive the contrast signals and operative selectively to render the first or second means operative, and look-ahead means connected to receive the PEL values successively stored in a first group of buffer positions and operative to generate a succession of selection signals indicative of whether any PEL value in each group lies in the band of values between the first and second threshold values or outside that band, each selection signal being associated with the PEL value occupying a particular location in the first group, being supplied to the selection means and being used by the selection means in selecting the operational mode of the apparatus.
Claim 6
Dependent Claim
279 words
Apparatus for reproducing an original represented by a serial stream of digital data, each item of data having a PEL value corresponding to the value of a surface characteristic (e.g. reflectance) of the elemental area (PEL) of the original represented by the item of data, said apparatus being capable of operating in more than one mode to produce copies of different or mixed nature (e.g. continuous tone, line or printed) originals and comprising: buffer means for receiving and buffering the serial stream of data; means for comparing the value of each item of data with first and second threshold values and operable to generate contrast signals indicative of whether the PEL value is greater than the first threshold value, between the threshold values, or below the second threshold value; first means effective in operation to cause the apparatus to operate in a first mode according to a first algorithm; second means effective in operation to cause the apparatus to operate in a second mode according to a second algorithm; selection means connected to receive the contrast signals and operative selectively to render the first or second means operative, and look-ahead means connected to receive the PEL values successively stored in a first group of buffer positions and operative to generate a succession of selection signals indicative of whether any PEL value in each group lies in the band of values between the first and second threshold values or outside that band, each selection signal being associated with the PEL value occupying a particular location in the first group, being supplied to the selection means and being used by the selection means in selecting the operational mode of the apparatus.
Claim 7
Dependent Claim
27 words
4 Apparatus as claimed in claim 3 further comprising hysteresis means operable to generate and store hysteresis signals representative of preceding operational mode and/or preceding PEL values.
Claim 8
Dependent Claim
83 words
Apparatus as claimed in claim 4 in which the hysteresis means comprises a first x-counter and a first y-counter associated with a first mode of operation of the apparatus, a first predetermined value being set in the counters in response to detection by the apparatus of a first predetermined data sequence in the incoming stream of data and the values in the first counters being decremented in response to detection of a subsequent second predetermined data sequence in the incoming stream of data.
Claim 9
Dependent Claim
84 words
Apparatus as claimed in claim 5, in which the hysteresis means further comprises a second x-counter and a second y-counter associated with a second mode of operation of the apparatus, a second predetermined value being set in the second counters in response to detection by the apparatus of a third predetermined data sequence in the incoming stream of data and the values in the second counters being decremented in response to detections of a subsequent fourth predetermined data sequence in the incoming data sequence.
Claim 10
Dependent Claim
56 words
Apparatus as claimed in claims 6 or 7, in which the stream of incoming data is generated by scanning the original in the y-direction and in which the or each y-counter has an associated serial storage shift register having a number of stages equal to the number of PELs in the y-scan direction of the original.
Claim 11
Dependent Claim
155 words
Apparatus as claimed in anyone of claims 3 to 7, further comprising gradient means connected to receive the PEL values stored in a second group of buffer positions and operative to generate for each second group a gradient signal, the gradient signal being associated with the particular PEL value occupying a predetermined buffer location in the second group and having a value dependent on the rate of change of the surface characteristic in a region of the original contiguous to the PEL corresponding to the particular PEL value; and means for comparing the value of each generated gradient signal with a predetermined datum gradient value and operable to generate transition signals indicative of whether the value of each generated gradient signal is greater or smaller than the datum gradient value, said transition signals being supplied to the selection means and being used by the selection means in selecting the operational mode of the apparatus. -
Claim 12
Dependent Claim
329 words
Apparatus for reproducing an original represented by a serial stream of digital data, each item of data having a PEL value corresponding to the value of a surface characteristic (e.g. reflectance) of the elemental area (PEL) of the original represented by the item of data, said apparatus being capable of operating in more than one mode to produce copies of different or mixed nature (e.g. halftone, line or printed) originals and comprising: buffer means for receiving and buffering the serial stream of data; means for comparing the value of each item of data with first and second threshold values and operable to generate contrast signals indicative of whether the item value is greater than the first threshold value, between the threshold levels or below the second threshold value; gradient means connected to receive the PEL values stored in a first group of buffer positions and operable to generate for each first group a gradient value signal which is associated with the PE L value occupying a particular location in the first group; means for comparing the generated gradient values with a predetermined datum gradient value and operable to generate transition signals indicative of whether the generated gradient value is greater or less than the predetermined datum gradient value; and controller means, connected to receive the stream of digital data together with the transition signals; for selecting the operational mode of the apparatus, said apparatus being characterized by further comprising look-ahead means connected to receive the PEL values stored in a second group of buffer positions and operable to generate a selection signal for each group indicative of whether any PEL value in the group lies in the band of values between the first and second threshold values or outside that band, each selection signal being associated with the PEL value occupying a particular location in the second group, being supplied to the controller means, and being used by the controller means in selecting the operational mode of the apparatus.
Claim 13
Dependent Claim
329 words
Apparatus for reproducing an original represented by a serial stream of digital data, each item of data having a PEL value corresponding to the value of a surface characteristic (e.g. reflectance) of the elemental area (PEL) of the original represented by the item of data, said apparatus being capable of operating in more than one mode to produce copies of different or mixed nature (e.g. halftone, line or printed) originals and comprising: buffer means for receiving and buffering the serial stream of data; means for comparing the value of each item of data with first and second threshold values and operable to generate contrast signals indicative of whether the item value is greater than the first threshold value, between the threshold levels or below the second threshold value; gradient means connected to receive the PEL values stored in a first group of buffer positions and operable to generate for each first group a gradient value signal which is associated with the PE L value occupying a particular location in the first group; means for comparing the generated gradient values with a predetermined datum gradient value and operable to generate transition signals indicative of whether the generated gradient value is greater or less than the predetermined datum gradient value; and controller means, connected to receive the stream of digital data together with the transition signals; for selecting the operational mode of the apparatus, said apparatus being characterized by further comprising look-ahead means connected to receive the PEL values stored in a second group of buffer positions and operable to generate a selection signal for each group indicative of whether any PEL value in the group lies in the band of values between the first and second threshold values or outside that band, each selection signal being associated with the PEL value occupying a particular location in the second group, being supplied to the controller means, and being used by the controller means in selecting the operational mode of the apparatus.
Claim 14
Dependent Claim
173 words
Method for reproducing mixed format documents comprising the following steps: generating a stream of PEL video data representative of the informational contents of the mixed format document; utilizing a first discriminator to determine if the PEL represents line copy or nonline copy and to generate a stream of simulated PELs; utilizing a second discriminator to process either the PEL video data or the stream of simulated PELs and to generate a stream of decision classifying the process PELs as line copy or nonline copy; utilizing a third discriminator to examine the stream of decisions to reclassify the decision of any PEL which is different from surrounding P ELs and to generate an adjusted stream of decision classifying the process PELs as line copy or nonline copy; thresholding the stream of PEL video data against a first thresholder for PELs identified as line copy by the adjusted stream of decision; and thresholding the stream of PEL video data against a second thresholder for PELs identified as nonline copy by the adjusted stream of decision.
Claim 15
Dependent Claim
173 words
Method for reproducing mixed format documents comprising the following steps: generating a stream of PEL video data representative of the informational contents of the mixed format document; utilizing a first discriminator to determine if the PEL represents line copy or nonline copy and to generate a stream of simulated PELs; utilizing a second discriminator to process either the PEL video data or the stream of simulated PELs and to generate a stream of decision classifying the process PELs as line copy or nonline copy; utilizing a third discriminator to examine the stream of decisions to reclassify the decision of any PEL which is different from surrounding P ELs and to generate an adjusted stream of decision classifying the process PELs as line copy or nonline copy; thresholding the stream of PEL video data against a first thresholder for PELs identified as line copy by the adjusted stream of decision; and thresholding the stream of PEL video data against a second thresholder for PELs identified as nonline copy by the adjusted stream of decision.
Claim 16
Dependent Claim
32 words
A method as claimed in claim 10, further including using the values outputted from the thresholder to drive a bilevel printer so that a copy of the mixed format document is reproduced.
Claim 17
Dependent Claim
165 words
A method as claimed in claim 11, in which the first discriminator employs a defocus/symmetry technique and includes the following steps: .generating a first stream of simulated pixels with each simulated pixel being formed from a horizontal weighted average of an original pixel of interest and its surrounding neighbours; generating a second data stream of simulated pixels with each simulated pixel being formed from a vertical weighted average of the original pixel of interest and its surrounding neighbours; computing a gradient (G H ) for the simulated pixel of the first data stream; computing a gradient (G v ) for the simulated pixels of the second data stream; computing an overall gradient (G)= (G V -G H ); comparing the overall gradient G with a predetermined threshold level; characterizing the original PEL as line copy for G having a value more than the predetermined threshold level; and characterizing the original PEL as nonline copy for G having a value less than the predetermined threshold level.
Claim 18
Dependent Claim
93 words
A method as claimed in claim 12, in which the third disciminator employs an information homogeneity technique includes the following steps: a) generating line copy (LC)/nonline copy (NLC) decisions for the original PELs of interest; b) generating a map for the decisions; c) calculating a misclassification probability P for the PEL, with the misclassification probability being based on PEL surroundings and . hysteresis; d) generating a predetermined threshold level; e) comparing the probability P with the threshold level; and f) reclassifying the decision for PELs whose probability P are less than the threshold.
Claim 19
Dependent Claim
35 words
A method as claimed in claim 13, further including the steps of switching the decision for PELs having a probability (P) greater than the threshold; raising the threshold level; and repeating steps (c) through (f).
Claim 20
Dependent Claim
190 words
Apparatus for reproducing mixed format documents comprising: means for including an optical scanner for generating a stream of PEL video data representative of the informational contents of the mixed format document; a first discriminator means coupled to the scanner, said first discriminator means being operable for determining the characteristic of the PEL and for generating a stream of simulated PELs; a second discriminator means coupled to the first discriminator means, said second discriminator means being operable for processing either the PEL video data or the stream of simulated PELs and to generate a stream of decisions classifying the processed PELs as line copy or nonline copy; a third discriminator means coupled to the second discriminator means, said third discriminator means being operable to examine the stream of decisions to reclassify the decision of any PEL which is different from surrounding PELs and to generate an adjusted stream of decision classifying the process PELs as line copy or nonline copy; means coupled to the third discriminator, said means being operable for thresholding line copy PELs; and means coupled to the third discriminator, said means being operable for thresholding nonline copy PELs.
Claim 21
Dependent Claim
190 words
Apparatus for reproducing mixed format documents comprising: means for including an optical scanner for generating a stream of PEL video data representative of the informational contents of the mixed format document; a first discriminator means coupled to the scanner, said first discriminator means being operable for determining the characteristic of the PEL and for generating a stream of simulated PELs; a second discriminator means coupled to the first discriminator means, said second discriminator means being operable for processing either the PEL video data or the stream of simulated PELs and to generate a stream of decisions classifying the processed PELs as line copy or nonline copy; a third discriminator means coupled to the second discriminator means, said third discriminator means being operable to examine the stream of decisions to reclassify the decision of any PEL which is different from surrounding PELs and to generate an adjusted stream of decision classifying the process PELs as line copy or nonline copy; means coupled to the third discriminator, said means being operable for thresholding line copy PELs; and means coupled to the third discriminator, said means being operable for thresholding nonline copy PELs.
Claim 22
Independent Claim
172 words
A method for classifying mixed format documents into line copy (LC) and nonline copy, said method having the following steps: generating a stream of original pixels representative of the informational contents of the documents; generating a first stream of simulated pixels with each simulated pixel being formed from a horizontal weighted average for an original pixel of interest and its surrounding neighbours; generating a second data stream of simulated pixels with each simulated pixel being formed from a vertical weighted average for the original pixel of interest and its surrounding neighbours; computing a gradient (G H ) for the simulated pixel of the first data stream; computing a gradient (G ) for the simulated pixels of the second data stream; computing an overall gradient (G) = G V -G H ; comparing the overall gradient G with a predetermined threshold level; characterizing the original PEL as line copy for G less than the predetermined threshold level; and characterizing the original PEL as nonline copy for G greater than the predetermined threshold level.
Claim 23
Independent Claim
172 words
A method for classifying mixed format documents into line copy (LC) and nonline copy, said method having the following steps: generating a stream of original pixels representative of the informational contents of the documents; generating a first stream of simulated pixels with each simulated pixel being formed from a horizontal weighted average for an original pixel of interest and its surrounding neighbours; generating a second data stream of simulated pixels with each simulated pixel being formed from a vertical weighted average for the original pixel of interest and its surrounding neighbours; computing a gradient (G H ) for the simulated pixel of the first data stream; computing a gradient (G ) for the simulated pixels of the second data stream; computing an overall gradient (G) = G V -G H ; comparing the overall gradient G with a predetermined threshold level; characterizing the original PEL as line copy for G less than the predetermined threshold level; and characterizing the original PEL as nonline copy for G greater than the predetermined threshold level.
Claim 24
Independent Claim
121 words
An apparatus for reproducing mixed format documents comprising: a) means for generating a first stream of pixels representative of the information contents of the documents; b) means for comparing the value for each pixel with a first and a second threshold value; c) means for generating a second stream of pixels for the pixels having a value between the first and second threshold values; d) means for testing the pixels in the second stream of pixels for pixels that are part of a high frequency pattern; e) means for classifying the high frequency pixels into line copy pixels or nonline copy pixels; and f) means for thresholding the classified pixels against an appropriate thresholder to generate a print or no-print signal.
Claim 25
Independent Claim
121 words
An apparatus for reproducing mixed format documents comprising: a) means for generating a first stream of pixels representative of the information contents of the documents; b) means for comparing the value for each pixel with a first and a second threshold value; c) means for generating a second stream of pixels for the pixels having a value between the first and second threshold values; d) means for testing the pixels in the second stream of pixels for pixels that are part of a high frequency pattern; e) means for classifying the high frequency pixels into line copy pixels or nonline copy pixels; and f) means for thresholding the classified pixels against an appropriate thresholder to generate a print or no-print signal.
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