JPS6142310B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a highly reliable mark reading method. In the conventional mark reading method, there is no constraint on the number of marks when writing marks on a mark sheet, so immediately after reading the mark sheet and determining the presence or absence of marks written on it, it is necessary to assign meaning to the marks written on it. This method has a disadvantage in that it is difficult to check whether the presence or absence of a mark written on a mark sheet has been accurately determined before the test is performed. Furthermore, in the conventional mark reading method, it is difficult to accurately read marks written thinly or thinly with a pencil or the like by distinguishing them from noise such as dust or unerased marks. An object of the present invention is to provide a mark reading method that can determine whether or not marks written on a mark sheet have been accurately read during mark reading. Another object of the present invention is to provide a mark reading method that retries mark reading when the mark cannot be read accurately. In order to achieve the above object, the present invention divides mark fields arranged on a mark sheet into a plurality of subsets, and uses one of the mark fields included in each subset as a parity mark. To,
A mark writing rule is established to make the number of marks written in the subset an even or odd number, and it is checked whether the count of marks written in the subset is an even number or an odd number to ensure that the marks are read correctly. If the mark is not read normally, the mark reading is attempted again by changing the conditions for determining whether or not there is a mark written in the mark column. Here, changing the conditions for determining the presence or absence of an entry mark in the mark column and retrying has the following meaning. When reading a mark on a mark sheet, the width of the mark written in the mark column is detected, and if the width of the mark is greater than a predetermined value (M), it is determined that there is a mark. Although it can read thin marks, it is susceptible to noise from dust and unerased marks. On the other hand, if M is set large, it is strong against noise contamination, but thin or thin marks cannot be read. Therefore, in the present invention, in the first mark reading, for example, M
By setting M to a large value, marks can be read in a way that is resistant to noise contamination.On the other hand, in retrials based on the judgment result of parity check, M can be set to a small value to enable thin or thin marks to be read. . An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of a mark sheet related to the present invention, 101 is a mark sheet, 102
~104 are each partial area on the mark sheet 101,
105 to 107 are the positions of the mark columns (column direction)
Reference mark indicating , 108 to 128 are mark columns,
129 to 131 are parity mark columns. In the following explanation, the rules for filling in the parity mark fields 129 to 131 are as follows:
Total number of marks entered in mark fields 115 to 121 and parity mark field 130, mark field 122
-128 and parity mark column 131 so that the total number of marks entered is an even number. In FIG. 1, mark fields 111, 1
Please mark 12, 113, 118.
This shows that marks have been entered in the parity mark columns 129 and 130. Note that the marks entered in the mark field 111 are in the mark fields 112, 113, 1.
This indicates that the line width is thinner than the marks entered in 18 and parity mark columns 129 and 130. Now, assuming that the mark sheet 101 is main-scanned from left to right and sub-scanned from top to bottom, a method for detecting the presence or absence of marks written in the mark field from the image signal of one scanning line will be explained using FIG. do. In FIG. 2, 201 is a sample image signal of one scanning line that scanned the mark sheet 101, that is, scanning line A in FIG. Gate signal, 203 is mark column 108-114
and a mark detection gate signal for cutting out a part of the image signal 201 corresponding to the parity mark field 129. That is, the reference mark 105 can be detected by taking the AND of the image signal 201 and the reference mark detection gate signal 202. Moreover, if the image signal 201 and the mark detection gate signal 203 are ANDed, the mark fields 108, 109, 110, 11
4, a high level signal corresponding to the entry mark cannot be detected, but a high level signal corresponding to the entry mark can be detected in the mark fields 111, 112, 113 and the parity mark field 129. FIG. 3 shows an embodiment of the mark reading method of the present invention, which reads the mark sheet 101 shown in FIG.
9 is a block diagram of a mark reading system that determines the presence or absence of marks written in marks 9 to 131. In the figure, 301 is a facsimile transmitter that main-scans the mark sheet 101 from left to right and sub-scans it from top to bottom to output a facsimile signal f, and 302 receives the facsimile signal f and outputs the facsimile signal f.
The synchronization signal is separated and the image signal p for each scanning line is
and a synchronization signal separation circuit that outputs a synchronization signal s,
303 is a gate signal generation circuit that receives the synchronization signal s and outputs a reference mark detection gate signal g _k and a mark detection gate signal g _n ; 304 receives an image signal p and a reference mark detection gate signal g k and outputs a reference mark detection gate signal g _k and a reference mark detection gate signal g n; a reference mark detection circuit 30 that detects the presence or absence of the reference mark and outputs a control signal k representing the presence or absence of the reference mark;
5 is a mark discrimination circuit which receives the image signal p, mark detection gate signal g _n and control signal k and extracts mark information m; 306 receives mark information m and performs a parity check; if the parity is even, the mark information is A parity check circuit outputs m as is and outputs a control signal t if the parity is an odd number, and 307 is a processing device (temporarily assumed to be a computer) that receives mark information m. Next, the operation shown in FIG. 3 will be explained. First, the facsimile transmitter 301 scans the mark sheet 101 and outputs the facsimile signal f of the first scanning line. The synchronization signal separation circuit 302 receives the facsimile signal f and separates the synchronization signal s, and sends the synchronization signal s to the gate signal generation circuit 303 and the image signal p to the reference mark detection circuit 304 and mark discrimination circuit 305. The gate signal generation circuit 303 opens and closes the gate at predetermined timing based on the received synchronization signal s, thereby generating and outputting a reference mark detection gate signal g _k and a mark detection gate signal g _n . The reference mark detection circuit 304 receives the image signal p and the reference mark detection gate signal g _k ,
The number n _k of signals in which the image signal p is at a high level while the reference mark detection gate signal g _k is at a high level is counted, and it is determined whether or not the counted value n _k is larger than a predetermined reference value N _k . By this, the presence or absence of a reference mark is detected. The first scanning line is mark sheet 10
In this case, the reference marks 105 to 107 do not exist, so the count value n _k becomes n _k N _k , and the reference mark detection circuit 304 detects the reference mark. A control signal k (assumed = 0) indicating that is null is output. The mark discrimination circuit 305 receives the image signal p, the mark detection gate signal g _n , the control signal k, and the control signal t and discriminates the mark information m.
In the scanning of the first scanning line, k=0 and t=0 (assuming that the control signal t is initially set to t=0 in the initial state), so the process moves on to the next scanning line. This completes the operation regarding the first scanning line that scanned the mark sheet 101. In the second and subsequent scanning lines, the same process as in the first scanning line is repeated until the facsimile transmitter 301 scans the upper end of the reference mark 105 on the mark sheet 101. Next, a case will be described in which the facsimile transmitter 301 scans the upper end of the reference mark 105 on the mark sheet 101 (temporarily assumed to be the x-th scanning line). In this case, the facsimile transmitter 301, the synchronization signal separation circuit 302, and the gate signal generation circuit 303 repeat the same operations as those in the first scanning line. On the other hand, the reference mark detection circuit 304 has a count value n
_k is compared with a reference value N _k , and as a result, it is determined that n _k >N _k , and a control signal k (assumed = 1) indicating that the reference mark is present is output. The mark discrimination circuit 305 uses the image signal p and the mark detection gate signal g _n
, control signal k, and control signal t are received, and control signal k
=1, t=0 is detected. In this case, the mark discrimination circuit 305 counts the number of high-level signals of the image signal p included in each period in which the mark detection gate signal g _n is at a high level, and calculates the counted values n _n1 , n _n2 . . . n _n8
(The mark sheet 101 in FIG. 1 has seven mark fields per line and one parity mark field per line) is stored as mark preprocessing information _m'1 to _m'8 . With this, the processing regarding the x-th scanning line is completed. Next, a case will be described in which the facsimile transmitter 301 scans up to the lower end of the reference mark 105 on the mark sheet 101 (temporarily from the (x+1)th scanning line to the xth scanning line). In this case, a facsimile transmitter 301, a synchronization signal separation circuit 302, a gate signal generation circuit 303, a reference mark detection circuit 3
04 repeats the same operation as in the case of the x-th scanning line described above. On the other hand, the mark discrimination circuit 305 calculates the count value n _n1 +n _n2 . . . n _n8 similarly to the case of the x-th scanning line.
These counted values are added to each of the previously stored mark preprocessing information m' ₁ to m' ₈ and stored again. Next, a case will be described in which the facsimile transmitter 301 scans one scanning line below the lower end of the reference mark 105 on the mark sheet 101 (referred to as the (+1)th scanning line). In this case, the facsimile transmitter 301, the synchronization signal separation circuit 302, the gate signal generation circuit 303, and the reference mark detection circuit 304 are
Repeat the same operation as in the scanning line. The mark discrimination circuit 305 receives the image signal p, the mark detection gate signal g _n , the control signal k, and the control signal t, but since k = 0 and t = 0, the previously stored mark preprocessing information m' Mark condition ₁ ~ m′ ₈
It is compared with M ₀ to determine whether each of m' ₁ to m' ₈ is greater than the mark condition M _0. If m' _i > M ₀ , m _i = 1 (i = 1 to 8 ), in the case of m′ _i M ₀ , m _i =
Mark information m (=m ₁ ,
m ₂ ,...m ₈ ). In this example, marks are entered in the mark columns 111, 112, 113 and the parity mark column 128 in FIG.
Since the mark line width entered in the mark field 111 is narrow, the mark information m is m ₁ = m ₂ = m ₃ = m ₄ = m ₇ = 0, m ₅ =
Assume that m ₆ =m ₈ =1 is output. Note that the above m' ₁ to m' ₈ correspond to the mark widths written in the mark fields on the mark sheet. Parity check circuit 306 receives the mark information m, adds m ₁ to _{m 8} , determines whether the result is an even number, and outputs control signal t in accordance with the determination result. In this example

Since the following equation holds, the parity check circuit 306 outputs the control signal t=1. When the mark discrimination circuit 305 receives the control signal t=1, it changes the mark condition M ₀ to M ₁ (M ₁ <M ₀ ),
It is again determined whether each of the mark preprocessing information m' ₁ to m' ₈ is greater than the mark condition M ₁ , and if m' _i > M ₁ , m _i = 1 (i = 1 to 8). , m′ _i M ₁ , mark information m is set as m _i =0 (i=1 to 8)
(=m ₁ , m ₂ , ... m ₈ ) is output. In this example, after changing the mark condition M ₀ to M ₁ , mark field 1
11 thin marks can be detected, and the mark information m is m ₁ = m ₂ = m ₃ = m ₇ = 0, m ₄ = m ₅ = m ₆ = m ₈ =
It shall be output as 1. Next, the parity check circuit 306 receives the mark information m, adds m ₁ to _{m 8} again, determines whether the addition result is an even number, and outputs a control signal t according to the determination result. Output. In this example,
m _i =4=even, and the parity check circuit 306 outputs the control signal t=0. Parity check circuit 306 outputs mark information m ( _m8 corresponding to parity mark 129 may be excluded depending on the case) to computer 307. By the above operation, the entry mark drawn on the first line of the mark sheet 101 is transferred to the facsimile transmitter 3.
01 means that the data can be read and input into the computer 307. Thereafter, by repeating the same operation as described above for the second and subsequent lines of the mark sheet 101, the marks drawn on the mark sheet 101 can be input into the reading computer 307. However, in this example, the total number of marks entered in each of the second and third lines is determined by the parity check circuit 306.
Since even speed is detected at , the mark condition M ₀
The process of changing M to M ₁ and retrying mark discrimination does not work. Although not shown in this example, the mark information m=m ₁ received from the mark discrimination circuit 305 after the parity check circuit 306 outputs the control signal t=1
If the addition result of ~ _m8 is an odd number, the parity check circuit 306 sends the reject signal r to the computer 3.
07, and the computer 307 outputs the reject signal r
By receiving this, it is informed that the mark could not be read normally, and the corresponding reject process is performed. This reject processing is performed by the computer 30, for example.
There is a method such as outputting a message indicating that the mark sheet cannot be read to the typewriter attached to the printer. Note that the mark sheet shown in FIG. 1 is only an example. The shape and dimensions of the mark sheet, the number of mark fields and parity mark fields,
The shape, number of reference marks, and shape may be set arbitrarily. Furthermore, in the embodiment, a parity mark field is provided in each row of the mark field, but this is only an example of setting the parity mark field. A parity mark field may also be set. Also, the second
The mark detection means shown in the figure is only one example. Further, the mark reading system shown in FIG. 3 is only one example. For example, in the above description, when the parity check circuit determines that the parity is not an even number, the mark discrimination condition of the mark discrimination circuit is changed and the mark discrimination is retried, but this may be done for an odd parity. Further, the mark discrimination means and the reject processing means in this description are merely examples thereof. Also,
It is clear that even if a transmission line, modem, etc. are connected between the facsimile transmitter and the synchronization signal separation circuit, there will be no problem in the operation of the present system. As described above, the present invention has the advantage of realizing highly reliable mark reading by providing parity marks on a mark sheet and performing a parity check on the number of marks read when reading the mark sheet. Furthermore, according to the present invention, mark discrimination is retried by changing the conditions for determining the presence or absence of written marks based on the judgment result of the parity check, so that even thin or thin marks can be read while distinguishing them from noise caused by dust or unerased marks. becomes possible. Further, according to the present invention, since it is only necessary to make the sum of the number of marks an even number (or an odd number) for each subset of the mark field, the present invention has the advantage that the constraints on mark entry are simple. Furthermore, as shown in the embodiment, if the subset of mark fields to be parity checked is defined in line units, the same mark sheet reading system can be used for any format of mark sheets. I have it.

[Brief explanation of the drawing]

Fig. 1 shows an example of a mark sheet related to the present invention, and Fig. 2 shows a method for detecting the presence or absence of a mark written in a mark field from an image signal obtained by scanning the mark sheet shown in Fig. 1. 3 are block diagrams showing an embodiment of a mark reading system according to the present invention. 101...Mark sheet, 102-104...Partial area of mark sheet 101, 105-107...Reference mark, 108-128...Mark column, 129-
131... Parity mark field, 201... Image signal, 2
02... Reference mark detection gate signal, 203... Mark detection gate signal, 301... Facsimile transmitter, 302... Synchronization signal separation circuit, 303... Gate signal creation circuit, 304... Reference mark detection circuit, 3
05... Mark discrimination circuit, 306... Parity check circuit, 307... Computer.

Claims (1)

[Claims] 1 (a) One mark field has a width of multiple pixels in the main scanning direction and a width of multiple scanning lines in the sub-scanning direction, and the plurality of mark fields and the main scanning direction (b) a mark sheet having a plurality of subsets each consisting of a reference mark having a width of a plurality of pixels in the sub-scanning direction and a width of a plurality of scanning lines in the sub-scanning direction; use one of the mark fields as a parity mark field, (c) establish a mark writing rule that makes the number of marks written in the subset an even or odd number, and (d) scan by a facsimile transmitter, etc. In a mark reading method in which a mark is binarized and scanned and input by an input device and checked, for each subset (a) it is determined whether or not the target scanning line passes through the reference mark; Counting the number of black pixels at a position on the image signal corresponding to the reference mark, and if the number of black pixels is larger than a predetermined reference value, determining that the reference mark has been passed; If it is determined that the target scanning line passes through the reference mark, count the number of black pixels at each position on the image signal corresponding to the position of each mark field in the subset, and ( c) Adding the counted number of black pixels corresponding to each mark field to the values stored in a plurality of memories corresponding to each mark field and storing them, (d) Adding and storing the counted numbers of black pixels corresponding to each mark field; Counting the number of black pixels at a position on the image signal corresponding to each mark column for all of the plurality of scanning lines passing through the reference mark, and adding and storing the number of black pixels in the memory corresponding to each mark column. When the addition result is completed, the addition result value in each memory is compared with a threshold value that is initialized in advance, and if the addition result value in the memory is larger than the threshold value, it is determined that there is a mark. (E) After performing the above judgment on all of the memories corresponding to each of the plurality of mark fields, the total number of marks determined to be marked by the above judgment satisfies the mark writing regulations. (f) If they match, it is assumed that the mark has been read normally, the memory is set to the initial value, and the reading target is moved to the next subset; (g) If they do not match, then The threshold value is made smaller than the previous threshold value until a match is made, and the result of addition is compared with the numerical value of each addition in the memory, and the judgment of the presence or absence of a mark and the match check with the mark writing rules are repeated. A mark reading method characterized in that the threshold value and each memory content are set to initial values at the step 1, and the reading target is moved to the next subset.