FR2551281A1 - METHOD AND DEVICE FOR CONTROLLING THE MEMORY OF AN INDEPENDENT DRUM IMAGE ANALYZER DEVICE - Google Patents

Abstract

THE INVENTION RELATES TO A DRUM ANALYZER DEVICE, USED IN THE REPRODUCTION OF IMAGES TO, IN WHICH THE SCANNING AND RECORDING DRUMS 1, 2 INDEPENDENTLY ROTATE EACH OTHER, AND IN WHICH GRAPHICAL INFORMATION IS WRITTEN IN AT LEAST THREE LINE MEMORIES AND READ INTO THAT OF THE LINE MEMORIES WHICH IS NOT SUBJECT TO A WRITING OPERATION AT THIS TIME, IN ORDER TO PREVENT THE FORMATION OF A "RECORDING CONFUSION" IN THE IMAGED IMAGE .

Description

The present invention relates to a method and a device for controlling

  the memory of an image reproduction device, such as a color image analyzer device, and relates more particularly to a method and a device for an image analyzer system with independent drums, 5 having as input a scanning drum and at the output a recording drum rotating independently of each other.

  When an image is reproduced using a reproduction device such as a color image analyzer device used in photomechanical processing, the reproduced image must be recorded at a desired location on a photo-sensitive film Consequently, the graphic information obtained by scanning an original image is first stored in a memory and then read by a recording head. In this case, the magnification ratio of the main scanning direction coefficient depends on the ratio between the frequency of a write pulse intended to write the graphic information in the memory and the frequency of a read pulse intended to extract the graphic information from the memory, while the location of the recording depends on the start time of the reading

  graphic information in memory.

  In this connection, a conventional image analyzer device whose scanning and recording tam20 bursaries are coaxially connected to one another and rotate simultaneously (hereinafter referred to as the "coaxial type analyzer device") , generally uses line memories, each of which is capable of storing the graphic information of a scanning line. This system has the drawback of "recording confusion", however. 25 This "recording confusion" means that a recording line records graphic information corresponding to more than two scan lines Basically, when graphic information is written to or read from a memory, the read operation must be executed after the end of the writing operation However, when an input scanning position (angular position) and a recording position (angular position) are in a reciprocal relationship or in a ratio of specific enlargement, the read operation is executed

  before the end of the writing operation of the graphic information of the same scan line In such a case, it is thus the graphic information 35 of the previous scan line which is read instead of the baseline

  layout in progress, which causes said "recording confusion".

  To overcome the above-mentioned drawback, in a conventional manner it is ensured that the recording position (angular position) does not overlap the input scanning position (angular position). For example, 5 when record a reproduced image, an original image A is placed at an angular position from 0 to 180 of an original image drum 1, and a photosensitive film B according to the angular position from 180 to 360 of a recording drum 2 , as shown in FIG. 1 (a) When four images obtained by color separation are to be recorded, an original image A ′ is placed at an angular position from 0 to 72 of the original image drum 1, and four films corresponding to the separate colors Y (yellow), M (magenta), C (cyan) and K (black) are placed in this order at angular positions from 72 to 360 on the recording drum, as shown in the figure 1 (b) However, this process has the disadvantage that 1 5 areas usable on the two drums are limited, as is evident from the two examples above. The above-mentioned problem can be solved by using two memory lines, as shown in FIG. 2 (a, b), each being able to store the graphic information of a scanning line In FIG. 2 (a, b), each pulse P1 'P 2, P 3' is a pulse of revolution which is emitted by a rotary encoder which rotates, in connection with a scanning input drum, one revolution at each revolution of the latter In the interval separating the pulse P1 and the pulse P 2, the graphic information A 2 of a given scanning line are entries in a line memory M 1, while the graphic information A 1 of the previous scan line, which are already stored in a line memory M 2, are read in the line memory M 2 in the form of graphical record information B 1, which has been subject to conversion magnification and synchronism setting In the next interval between P 2 and P 3, the 30 graphics A 3 of the next scan line are entered.

  the line memory M 2, while the graphic information A 2 is read from the line memory M 1 in the form of graphic recording information B 2, which have been subjected to the abovementioned treatments. This procedure is repeated for all the following scan lines.

  In this regard, it is sometimes asked that certain reproduced images be enlarged To satisfy this requirement, the scanning and recording drums must naturally be of larger dimensions This implies that the two drums are hardly arranged coaxially, that a device for reproduction of images comprising drums of such a size in a single assembly is difficult to handle and transport, and that

  such a system finally requires a large space for its installation.

  This problem can be solved by assembling the input and output components separately (an image analyzer device of such a construction will be designated hereinafter by the term "independent drum analyzer device") In an analyzer device with independent drums, the two drums obviously rotate independently of each other Therefore, although two line memories are used, it can nevertheless occur

"registration confusion".

  More specifically, in an independent drum analyzer, an input scanning drum and a recording drum are rotated synchronously, with, in some cases, a certain phase difference Suppose now that the phase difference c between the two drums is t = (, as shown in FIG. 2 (a, b ') Until the first revolution pulse P1 is output, the graphical recording information B' 0 corresponding to the graphic scanning information A 2 (not shown in the drawings) are extracted from the line memory M 1 * In the interval separating the output of the pulse P1 and that of the first revolution pulse P'1, the scanning graphic information A 2 begins to be written to the line memory M 1, while the recording graphic information B'0 is still being read from the line memory M'1 Consequently, as in the sees in the case where only one line memory is used in the independent drum device, the situation described above also causes a "recording confusion" The same phenomenon also occurs when the phase difference t between the two drums is r = as shown

Figure 2 (a, b ").

  In order to eliminate this phase difference, motors intended for

  rotating the two drums must be controlled synchronously and in phase, which also requires a complex and expensive motor control circuit 35.

  The method proposed by the present invention aims to solve this classic problem. One of the fundamental aims of the present invention is to propose a method for controlling the line memories of an image analyzer device with independent drums, which is capable of eliminating the possibility 5 that the read operation occurs in competition with the write operation of the graphic information stored in an identical line memory, even if the scanning and recording drums of the device rotate synchronously with a certain difference More specifically, the independent drum analyzer device of the present invention 10 is provided with at least three line memories, the read operations and

  of writing being executed on different line memories.

  An embodiment of the method and of the device for controlling the line memories of an independent drum analyzer system according to the present invention will now be described in more detail, by way of nonlimiting example, with reference to the accompanying drawings, in which: FIG. 1 shows examples of positioning of the original images and the photo-sensitive films in a conventional analyzer device; FIG. 2 shows a timing diagram of a write pulse and a read pulse, in the case where two line memories are used; FIG. 3 shows an analyzer device implementing the method of the present invention; Figure 4 shows the difference of 180 between the phases of a write pulse and a read pulse; FIG. 5 shows a timing diagram of a write pulse and a read pulse, in the case where three line memories are used; FIG. 6 shows a timing diagram of a write pulse and a read pulse, in the case where four line memories are used; Figure 7 shows a memory system of the present invention; Figure 8 shows a memory unit of the memory system of Figure 7; Figure 9 shows another memory system of the present invention; and

  FIG. 10 shows an example of the use of random access memory.

  Figure 3 shows an independent drum analyzer device

  to which the method according to the present invention is applied.

  A sweep input drum 1 reviews a force of revolution of a motor 9 via a pulley 3, a belt 7 and another pulley 4, while a recording drum 2 reviews a force of revolution of a motor 10, via a pulley 5, a belt 8 and another pulley 6, as shown in FIG. 3 The graphical information obtained by scanning an original image A using an input scanning head 13 is entered into a calculation module 19, where it is subjected to a correction of colors and contrast, then entered into a system of memory 20 A revolution pulse P in and a synchronization pulse N N are entered into the memory system 20 from a rotary encoder 11 which is rotated coaxially 15 with the scanning input drum 1, while a Pout revolution pulse and a Nout synchronization N pulse are input from a ro encoder tative 12, rotated coaxially with the recording drum 2 The pin and Pout pulses of revolution and the Nin and Nout synchronization pulses N are used to control the 20-line memories (which will be described later) of the memory system 20 when

  the graphic information is written and read in the line memories.

  The graphic information read in the memory system 20 is applied to the input of a recording head 14 intended to record a reproduced image B. In this device, the belts used for the belts 7 and 8 are drive belts positive (toothed belts) and not flat belts which easily slip, in order to maintain synchronization between the motor 9 and the scanning input drum 1 as well as between the motor 10 and the recording drum 2 The ratio of trans30 mission between pulleys 3 and 4 is calculated to coincide with that of pulleys 5 and 6, in order to ensure that drums 1 and 2 rotate according to

the same angular speed.

  In a device thus designed, a phase difference a is created, represented in FIG. 2, in the following way: an electric current is applied simultaneously to the motors 9 and 10 from a current source 18 when a switch 17 is closed, and the motors 9 and 10 therefore start to rotate synchronously At this stage, even if the revolutions of the motors 9 and 10 are synchronized, the drums 1 and 2 do not always rotate in the same phase, since the ratio transmission of pulleys 3 and 4 is not 5 1: 1, and that of pulleys 5 and 6 is not similarly,

1: 1.

  In addition, the motors 9 and 10 being loaded differently, the starting characteristics of the two motors also differ.

  another coefficient in the apparent phase difference r.

  Consequently, as can be deduced from the relationship between FIGS. 2 (a) and 2 (b "), the rotary encoders 11 and 12 deliver at the outputs

  Pin and PO pulses of revolution, which translate the phase difference (-180 <<+ 180) between each of them, as shown in Figure 4.

  When a memory system 20 is provided with three line memories 15 M 1, M 2 M 3, each of which is capable of storing graphic information

  of a scanning line, the graphical information is written into the line memories according to the pin of revolution pulse, and is read according to the Pout of revolution pulse, as shown in FIG. 5 FIG. 5 comprises several case of read synchronization determined by the delivery of a P Out pulse (outu t 1 'Pout) of revolution, compared to that of the Pin revolution pulse.

  Under these conditions, the graphic information coming from each scanning line is written into the three line memories M 1, M 2, M 3, successively as a function of the pin of revolution pulse When the writing operation begins at be executed on one of the line memories (on the order represented by the Pin of revolution pulse, represented in broken lines in FIG. 5), the read operation is in progress on the line memory which stores the graphic information of the second previous scan line That is to say that, for example, when the write operation begins on the line memory M 1, the read operation is in progress on the line memory M 2 When the line memories M 1, M 2 and M 3 are controlled in the above-mentioned manner, the write and read operations are not executed simultaneously on the same line memory, except in the following case: When the Pout of revolution impulse phase p feels a slight

255 1281

  delay compared to that of the pulse P 1 of revolution, as represented by P out 5 in FIG. 5, the write and read operations fall

  accidentally on the same line memory.

  Practically, however, the overlap is less than 0.75 In other words, if the circumference of the recording drum is 1800 mm, it is less than 3.75 mm This proportion is not significant and may

therefore be overlooked.

  FIG. 6 represents a timing diagram of the method of the invention,

  in which four line memories are used in order to avoid the above-mentioned problem.

  Under these conditions, the graphic information of each scanning line is written to four line memories M 1, M 2, M 3 and M 4 successively as a function of the pulse Pin of revolution When the writing operation is half executed (angle of 180) on a line memory, the reading operation is in progress on the line memory which retains the graphic information of the second previous scan line. This means that, for example, when the the write operation is half performed (angle of 180) on the line memory M 1 (as shown in broken lines in FIG. 6), the read operation is in progress on the line memory M 3 When the write operation is less than half executed (angle

  between O and 180) on the line memory M 1 (as shown in dashed lines in FIG. 6), the read operation is in progress on the line memory M 3 or M 2 In this case the operations d writing and reading never fall on the same line memory.

  Figure 7 shows a block diagram of a memory system for

  implement the method of the invention.

  In FIG. 7, a counter 22 and an AND gate 24 form a ternary counter for the input side. That is to say that when the number counted by the counter 22 changes to "3", the AND gate 24 delivers a signal "H "(level 30 high) at the reset terminal, this signal resetting the number counted by counter 22. Furthermore, a counter 23 and an AND gate 25 form another ternary counter for the output side, which has the same function

than the previous one.

  A flip-flop circuit 44, constituted by NAND gates 42 and 43, 35 is activated by a starting pulse Sp, which is applied to its input

  when the motors 9 and 10 start to rotate synchronously The signal output by the flip-flop circuit 44 and the Pin of revolution pulse cause a NAND gate 41 to output a loading signal applied to the terminals of loading of the counters 22 and 23 At the same instant, the loading si5 is applied to the input of the NAND gate 43, to reset the flip-flop circuit 44.

  When the initial digit counted by counter 22 is "O" and

  that counted by the counter 23 is "1", the two counters begin to operate from the figures "O" and "1" which are given to them respectively 10 on the order of the loading signal.

  The counter 22 outputs, to a decoder 26, a signal corresponding to the number counted by itself, which varies according to the sequence O 1 2 -O- 1-_ 2, while the counter 23 delivers, to a decoder 27, a signal corresponding to the digit counted by itself, which varies according to the sequence 1-2-2 O-01-2-0 By decoding these signals, the decoder 26 outputs

  a signal WE authorizing the writing, and the decoder outputs a signal RE authorizing the reading to the line memories M 1, M 2 and M 3 respectively in the memory units 34, 35 and 36.

  On the other hand, said synchronization pulse N N delivered at the output of the rotary encoder 11 on the input side, is applied to the input of a synthesizer 28 This synthesizer 28 multiplies the frequency of the synchronization pulse Nin by an enlargement coefficient MD, and outputs the product, in the form of a synchronization pulse fw, to an A / D converter 21 The analog graphic information delivered at the output of the calculation module 19 is then converted into information corresponding digitized graphics, in synchronism with the synchronization pulse fw, then applied to the input of the line memories M 1, M 2 and M 3 The synchronization pulse fw is also applied to the input of a counter 29 , whose output signal, namely the counted digit, is applied to the input of the line memories M 1, M 2 and M 3, in the form of a write address signal WRADD, by via RAM

  31 (which will be described later).

  The synchronization pulse Nout N delivered by the rotary encoder 12 on the output side is applied to the input of a PLL circuit 33, and subjected to a frequency multiplication, to be applied to the input of a counter. , in the form of a synchronization pulse en The output signal (number counted) from counter 30 is applied to the input of the line memories M 1, M 2 and M 3, in the form of a signal READD read address, via RAM 32 (which will be described later). 5 The read and write operations are executed on the line memories M 1, M 2 and M 3 as a function of the signal WE authorizing the writing, of the signal RE authorizing the reading, of the signal WRADD of writing address and of the read address signal READD thus obtained In this way, when for example the write operation is executed on the line memory M, the read operation is executed on the line memory M 2, thus as previously described The magnification coefficient MD can be expressed in the form fw / fr (with f W = frequency of the writing pulse; and fr = frequency of the reading pulse) The counters 29 and 30 are reset to zero

  respectively by the Pin and Pout revolution pulses.

  The RAM 31 is used to process the graphic information of several original images Aa and Ab, arranged as shown in FIG. 10 on the scanning input drum 1 (represented in the form of an expanded table). that when the magnification coefficient MD is sufficiently high, the volume of graphic information of a scanning line can sometimes exceed the capacity of a line memory M 1

  (M 2, M 3) In such a case, the random access memory RAM 31 provides the locations A Da and A Db in the line memory for the graphic information of the original images A a and Ab, as shown in FIG. 10.

  A random access memory RAM 32 is used to collect as output the graphic information of an original image several times in the direction

  main scan (regardless of the magnification).

  RAM memories 31 and 32 can be eliminated, by using preset counters instead of counters 29 and 30 and by doing

  vary the numbers initially counted by these preset counters.

  FIG. 8 shows a block diagram of each of the memory units 34, 35 and 36, which respectively comprise the line memories M 1 M 2 and M 3 When the decoder 26 delivers as an output, to one of the

  memory 34 (35, 36) a signal WE authorizing a writing of level "L" (ni35 calf low), graphic information is applied on the terminals of

  input / output of line memory 58, via a buffer 51 The signal delivered by a NON gate 53 then passing to level "H" (high level), the signal WRADD of write address is applied at the entry of line memory 58, via an AND gate 55 and an OR gate 57 Consequently, the graphic information is written in line memory 58

  in frncticn of the write address signal WRADD.

  When the decoder 27 outputs, to one of the memory units 34 (35,36), a signal RE authorizing a reading of level "L" (low level), the output signal of a gate NO 54 passes at level "H" (high level) 10 to apply the READD signal of read address to the line memory 58, via an AND gate 56 According to this READD signal of read address, the graphic information stored in line memory 58 is output from the input / output terminal of line memory 58, by means of a buffer 52 The signal WE authorizing a writing and the signal RE authorizing a reading never go to "L" level at the same time When the two signals are at "H" level simultaneously, the

  line memory 58 is disconnected.

  Figure 9 shows a block diagram of a device

  implements the method of the present invention The explanation which follows only relates to the part which is different from the device of FIG. 6.

  A reset signal intended for a flip-flop circuit 44 is generated in the following manner: The pulse N inde synchronization N delivered by the rotary encoder 11 is applied to the input of a counter 61 When the number counted by the counter 61 becomes greater than more than half the frequency of the pulse N in, the reset signal is delivered by a circuit of

  coincidence 62 When the reset signal is applied to the input of a NAND gate 41, the latter outputs a loading signal to the counters 22 and 23 as well as to the NAND gate 43, in order to reset the flip-flop circuit 44 Consequently, the line memory which must be used is determined at the moment when the revolution of the scanning input drum passes through the angular position point 180 after the pulse N indes synchronization N has been delivered (instant T in FIG. 6).

  Counters 22 and 23 are hexadecimal counters. Consequently, each of the two lowest bits of the counted count finds the same value every 35 counts. Thus, when the initial digits counted by the counters,

  1 1 teurs 22 and 23 are respectively "O" and "2", the counters 22 and 23 start to count respectively the pulses Pin and Pout of revolution, according to the loading signal The figure counted by the counter 22 varies according to the sequence 0 -1 2 3-0-_ 1 _ 2 3, while that of counter 5 23 varies according to the sequence 2-e 3-0-_ 1 _ 2 3-_ O 1 Depending on the signals delivered at the output of the counters 22 and 23, the decoder 26 outputs the signal WE authorizing a writing, and the decoder 27 outputs the signal RE authorizing a reading In this device, as in the device in FIG. 6, the reading operation is executed on line memory 10 of line M 1 when for example the write operation is executed on line memory of line M 2 As described above, the method according to the invention makes it possible to

  remedy the classic problem of "recording confusion", by using three line memories instead of a complex circuit for controlling synchronous motors when the scanning and recording input drums independently rotate one of the other according to a relation of synchronism.

  The implementation of the method of the invention therefore makes it possible to obtain a

  economical analyzer device with independent drums.

Claims (9)

  1 Method for controlling the memory of an independent drum analyzer device, in which graphic information obtained by scanning an original image (A) placed on a scanning input drum (1) 5 rotating independently of a drum recording (2), are first stored in a memory (20), then extracted to be used for recording a reproduced image (B), characterized in that it comprises the steps consisting in: ( a) write the graphic information of at least three lines of ba10 layering successively in the same number of line memories (M 1, M 2, M 3), in which a line memory corresponds to a scanning line; and (b) read the graphical information successively coming from one of the line memories (M 1, M 2, M 3) which is not being subjected to a write operation.   2 Method according to claim 1, characterized in that three line memories (M 1, M 2, M 3) are used.   3 Method according to claim 1, characterized in that at the instant when the write operation begins to be carried out on a line memory, the read operation is in progress on the line memory which stores the information graphics from the second previous scan line.   4 Method according to claim 1, characterized in that four line memories (M 1, M 2, M 3, M 4) are used.   Method according to claim 4, characterized in that at the instant   o the write operation is performed on half of a line memory, which corresponds to an angle of revolution of 180 of the scanning input drum (1), the read operation is in progress on the line memory which stores the graphic information of the second previous scan line.   6 Device for controlling the memory of an independent 30-drum analyzer device, in which graphic information obtained by scanning an original image (A) placed on a scanning input drum (1) rotating independently of a drum recording (2), are first stored in a memory (20), then extracted to be used for recording a reproduced image (B), characterized in that it comprises: 35 (a) at at least three line memories (M 1, M 2, M 3); (b) writing means for carrying out the writing operation on one of the three or more line memories (M 1, 2 M 3) designated successively; and   (c) a reading means for carrying out the reading operation on one of the line memories (M 1, M 2, M 3) which is not being subjected to the operation of writing.   7 Device according to claim 6, characterized in that: (a) it comprises at least three line memories (M 1, M 2, M 3); (b) the writing means comprises a generator (26) of auto10 signal risking a writing to deliver at the output a signal authorizing a writing (WR) to the three or more of three line memories (M 1, M 2, M 3) successively at each revolution of the scanning input drum (1) and an address signal generator for outputting a common write address signal (WRADD) to each line memory (M 1, M 2, M 3); and (c) the reading means comprises a signal generator authorizing a reading to output a signal authorizing a reading (RE) to the three or more of three line memories (M 1, M 2, M 3 ) successively   each revolution of the recording drum (2) and an address signal generator for outputting a common read address signal 20 (READD) to each line memory (M 1, M 2, M 3) .   8 Device according to claim 7, characterized in that: (a) three line memories (M 1, M 2, M 3) are used; (b) the means for generating a signal authorizing a writing comprises a ternary counter (22) for counting pulses (Pin) generated on each revolution of the scanning input drum (1) and a decoder (26) for decoding the digit counted by the counter (22) in order to output a signal authorizing a writing (WR); and (c) the means for generating a signal authorizing a reading comprises   a ternary counter (23) for counting pulses (Pout) generated at each revolution of the recording drum (2) and a decoder (27) for decoding the number counted by the counter (23) in order to output a signal authorizing a reading (R).   9 Device according to claim 7, characterized in that: (a) four line memories (M 1, M 2, M 3, M 4) are used;   (b) the means for generating a signal authorizing a complex writing   takes a hexadecimal counter (22) to count pulses (Pin) generated with each revolution of the scanning input drum (1) and a decoder (26) to decode the two lowest bits of the number counted by the counter (22 ) in order to output a signal authorizing a write (WR); and 5 (c) the means for generating a signal authorizing a reading comprises a hexadecimal counter (23) for counting pulses (Pout) generated with each revolution of the recording drum (2) and a decoder (27) for decoding the two lowest bits of the number counted by the counter (23) so   to output a signal authorizing a reading (R).   10 Device according to claim 8 or 9, characterized in that it comprises a flip-flop circuit (44) which is activated by a starting pulse (Sp) delivered when the revolution of the scanning input drum (1) is in synchronism with that of the recording drum (2), and which is reset by the next first pulse (Pin) generated at each revolution of the scanning input drum (1), the flip-flop circuit (44) making   so that, when it is reset, said two counters (22, 23) start counting from their respective preset values corresponding to the memories (M 1, M 2, M 3, M 4) to be controlled.