JP2641671B2 - Mark reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mark reading device for reading a mark written on a mark sheet prepared according to a predetermined format by an optical reading device.
You.

[0002]

2. Description of the Related Art Normally, in this type of mark reading method, for example, mark sheets 1 and 2 as shown in FIGS. 1 and 2 are read by a reading device by sequential scanning, and an image signal obtained by the scanning is read. First, the start reference mark 3 in FIG. 1 and the start reference mark 4 and the stop reference mark 5 in FIG. 2 are detected. Then, based on those detection positions, it is determined which section of one scanning line corresponds to each of the mark entry columns 6 and 7 (the mark entry columns 6 and 7 on the mark sheets 1 and 2 correspond to the reference entry). The marks are in a predetermined positional relationship with the marks 3, 4, and 5), and it is determined whether or not a mark is entered in each of the mark entry columns 6 and 7 by referring to the image signal of the determined section. I do.

Here, whether or not the above-mentioned mark is entered
Is determined by reading all the image data on the mark sheet.
And after storing these in memory once
Method or a method that is performed simultaneously with reading the mark entry field
Had gone by. In addition, as a scanning line used for determination,
In the case of the mark sheet 1 in FIG. 1, the start reference mark
The image signal of the scanning line where No. 3 is detected is converted to a mark sheet shown in FIG.
In the case of 2, the start reference mark 4 and the strike
Of the scanning line in which both of the reference marks 5 are detected simultaneously.
The determination was made with reference to the respective signals.

[0004]

The present invention is, however, the slave
If the former method is used,
All image information must be temporarily stored in memory.
Image information for at least one page of the mark sheet can be stored
The challenge is that a memory with a large capacity is needed.
Was. In the latter case, after reading and determining,
Mark sheet to process mark entry field of next line
The problem that it takes a lot of processing time to transport
there were.

The present invention has been made to solve the above-mentioned conventional problems, and does not require a large-capacity memory.
Mark reading that can determine whether or not a mark has been entered in the mark entry field in a short processing time
It is intended to provide a device .

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has a mark entry field and a start of the mark entry field.
A pair of fiducial marks indicating the end
Reading means for reading the mark sheet,
Discriminate black and white of the image signal input from the
Is detected as a reference mark when a black signal
Fiducial mark detecting means for detecting a fiducial mark;
Detection of the fiducial mark in response to the read transition of the worksheet
A register for storing data indicating a state, and the register
At least one of the fiducial marks based on the data in
In the state where either one is detected,
When a transition is made to a state where no
Line for determining whether or not a mark is entered in each column
Data processing is repeated for each of a plurality of lines in the mark entry column
And a control means for executing.

[0007]

According to the present invention, a mark sheet is formed on the mark sheet by the above-described structure.
It is not necessary to temporarily store all image information in the memory
Therefore, a large-capacity memory is not required. Also, both reference markers
Mark transitions to a state where both sides are not detected.
Short processing time to determine whether or not
Can be used to perform the determination process.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. In this embodiment, the mark sheet 12 shown in FIG. 3 is used. The mark sheet 12 will be described in more detail. The start reference marks 10 are provided in the vertical direction near the left end of the mark sheet 12. On the other hand, the stop reference mark 11 is
In the vicinity of the right end of the mark sheet 12, they are provided side by side in the vertical direction. The reference marks 10 and 11 occupy symmetrical positions on the mark sheet 12.

The two reference marks 10 and 11 are each a rectangle having a length of 4 mm and a width of 3 mm. The reference marks 10 and 11 have a color (for example, black) that can be read by a reading device such as a facsimile machine. It is printed on solid.

Each line of the mark entry column 8 is provided in a region sandwiched between a pair of start reference marks 10 and stop reference marks 11, respectively. These mark entry columns 8 are 4 mm long and 1 mm wide, and are colors that cannot be read by the reading device (for example, pale green).
Is printed in white. The horizontal interval A of the mark entry column 8 is 4 mm. Each line of the mark entry column 8 is a pair of start reference marks 1
It is aligned with 0 and the stop reference mark 11.

When the dimensions and problems of the reference marks 10 and 11 and the mark entry field 8 are determined as described above,
Assuming that the mark sheet 12 is A4 size, if an article column 9 described below is not provided, about 1400 (40 columns × 3
The mark entry column 8 (5 lines) can be set in one mark sheet 12.

The article column 9 includes a start reference mark 10
Are provided together with the mark entry field 8 in an area sandwiched between the row of the reference marks 11 and the row of the stop reference marks 11. The shape and size of the article column 9 can be appropriately determined.

FIG. 4 shows mark detection in this embodiment for detecting whether or not a mark has been entered in each mark entry field 8 based on an image signal obtained from a reading device (not shown) such as a facsimile machine. FIG. 2 shows a block diagram of the circuit. In the figure, reference numeral 15 denotes an image signal input terminal for inputting an image signal c obtained by the reading device, and 16 denotes an image signal clock pulse b (one clock pulse corresponds to one pixel) completely synchronized with the image signal c. A clock pulse input terminal input from the reader, an image signal section signal input terminal 17 for inputting an image signal section signal a from the reader, and a scan start signal input terminal 18 for inputting a scan start signal p from the reader.

Reference numeral 19 denotes an 8-bit general-purpose microprocessor for controlling each part of this circuit. The main operation of this circuit described later is performed by a ROM (Read Only Memory).
y) This is performed by the microprocessor 19 executing a program stored in advance at 20. 2
1 is a data bus, 22 is an address bus, and 23 is a control bus. 24 is a RAM (Random Access)
Memory 35 is an image input circuit for inputting image signals to the memory 35. The image input circuit 24 includes an 8-bit serial / parallel conversion register 25, a data latch 26,
/ 8 frequency divider 27, address counter 28, DMA control circuit 29 and status register 30.

The clock pulse b is supplied to the serial / parallel conversion register 25 and the 1/8 frequency divider 27.
Is input to Further, the 1/8 frequency divider 27 is activated by the image signal section signal a, and changes the clock pulse b to 1 /.
The pulse divided by 8 is sent to the data latch 26 and the DMA control circuit 29 as a latch pulse signal d.

Reference numeral 31 denotes each mark entry column 8 in one scanning line.
Is a black pixel counting circuit that counts the number of black pixels in the section corresponding to .times .. The black pixel counting circuit 31 includes a 1/8 frequency divider 32, an 8-bit parallel / serial conversion register 3,
3 and an integrating counter 34.

An output circuit 36 outputs the detected mark data to an external data processing device. The output circuit 36 includes an output data port 37, a data transfer control circuit 38, and an external interface 39.

FIG. 5 is a map diagram (area allocation diagram) of the RAM 35, FIG. 6 is an allocation diagram in the work area 40 of FIG. 5, FIG. 7 is an operation timing chart inside the image input circuit 24, and FIG. Operation timing charts inside the circuit 31, and FIGS. 14 to 16 are flowcharts showing the operation of the mark detection circuit.

Next, the operation of the mark detection circuit will be described with reference to these drawings. When the reading start position is reached, when the scanning start signal p becomes “1”, the section signal a becomes “1”, and the image signal c is synchronized with the input terminal 15.
(Note that the clock pulse b is always input to the input terminal 17).

Then, as described above, the section signal a is "1".
, The image input circuit 24 becomes operable,
As shown in the timing chart of FIG. 4, the image signal c serially input to the serial / parallel conversion register 25 through the input terminal 15 is converted into a parallel signal by 8 bits by the register 25, and then the data latch 2
6 is transferred. The 8-bit image signal transferred to the data latch 26 in this manner is then transferred to the RAM 35
The memory is directly transferred to the RAM 35 (hereinafter referred to as DMA), and is sequentially stored in the first input buffer area 41 or the second input buffer area 42 of the RAM 35.

The above operation is continuously performed while the section signal a is "1". As a result, the image signal c for one scanning line is stored in the input buffer area 41 or 42 continuously.

Here, the input buffer areas 41, 42
Has a capacity for one scanning line, and in order to improve the processing speed, while various processes to be described later are performed on an image signal c of a certain scanning line stored in one input buffer area. The image signal c of the next scanning line is stored in the other input buffer area.

In this embodiment, one scanning line has 2048 lines.
Since the input buffer areas 41 and 42 have a capacity of 2,048 / 8 = 256 bytes, respectively.

In the DMA transfer, a DMA request signal f and a DM request signal are transmitted between the DMA control circuit 29 and the processor 19.
After the exchange of the A response signal g, the DMA control circuit 29 sends the address valid signal h together with the memory write signal i.
Is output, and by this, the address bus 22 is validated, and at the same time, the image signal held on the data latch 26 is set up on the data bus 21 to realize this.

As described above, the input buffer area 41 or 42 of the RAM 35 receives the stored image signal.
First, reference marks 10 and 11 are searched. next,
This will be described.

In this embodiment, the reading device is 8 dots / 1 mm
It has a resolution of. Since the horizontal axis of the reference marks 10 and 11 is 3 mm as described above,
Ideally, the reference marks 10, 1 on one scanning line
1 will appear as black signals of 3 × 8 = 24 bits each. Therefore, in the present embodiment, when determining the reference mark in consideration of the printing accuracy of the mark sheet 12, the inclination of the mark sheet 12 at the time of reading, and the like, a continuous black signal has an allowable range in advance. Specifically, 24 ±
When three bits (that is, 21 bits (first predetermined value) or more and 27 (second predetermined value) bits or less) of black signals are continuous, it is assumed that the reference marks 10 and 11 have been detected.

The processing for the image signal stored in the input buffer area 41 or 42 is performed using the work area 40 (see FIGS. 6 and 7) of the RAM 35. In the initial state, this work area 40 is used. Each part of has been cleared.

The search operation for the fiducial marks 10 and 11 is specifically performed according to the flowchart of FIG.
That is, when the black signal is read out next to the white image signal, the microprocessor 19 uses the reference mark width counter 48 in the work area 40 of the RAM to count the number n of continuous black signals.
Is counted, and if 20 <n <28, it is determined that the reference marks 10 and 11 have been detected.

The reference mark detected in the first half of one scanning line is regarded as a start reference mark 10 while
The reference mark detected in the latter half of one scanning line is regarded as the stop reference mark 11.

In this embodiment, the trailing edge of the detected reference marks 10 and 11 (that is, the last black pixel of n consecutive black pixels) is set as a reference position, and information indicating this reference position is used as the reference position. The start reference mark position register 46 and the stop reference mark position register 47 in the work area 40 of the RAM are saved. The reference mark position register 4
The contents of 6, 47 are new reference marks 10, 1 respectively.
It is updated each time 1 is detected.

As described above, the first fiducial mark 10
Or 11 is detected (when the mark sheet 12 is inclined to the left, the stop reference mark 11 is detected earlier than the start reference mark 10), the search mode register 44 in the work area 40 of the RAM. Is set,
Thereafter, the mode shifts from the entire section search mode to the limited section search mode.

Here, in the all section search mode, the search operation of the reference marks 10 and 11 is performed in all sections of the image signal of each scanning line. However, after the first fiducial mark 10 or 11 is detected, the section in which the other fiducial marks 10 and 11 appear can be predicted. Only in the section, the fiducial marks 10, 1
1 is performed.

That is, in the limited section search mode, the first reference mark 10 or 11
Or the fiducial mark 10 or 11 detected thereafter
Based on the position information and the distance between the reference marks 10 and 11 registered in advance in the ROM 20, a limited section on a scanning line where a reference mark to be detected next can appear is determined based on a predetermined reference. Only in the limited section, a search operation for a fiducial mark to be detected next is performed.

Note that the position of the article column 9 is set so as not to be included in the limited section. FIG. 9 is a timing chart showing the relationship between the image signal and the limited area.

As a result, the reference mark 1 is displayed in the article column 9.
Even if a graphic pattern that cannot be distinguished from 0 or 11 is written, there is no possibility that the pattern is erroneously detected as the reference marks 10 and 11. Further, since the number of data to be searched is reduced, the processing speed is improved.

On the other hand, as described above, the first fiducial mark 10
Or, when 11 is detected, an operation of detecting whether or not a mark is entered in each mark entry column 8 is started. Next, this will be described.

In the reference mark detection register 45 in the work area 40 of the RAM 35, it is set for each scanning line whether or not the start reference mark 10 and the stop reference mark 11 have been detected, respectively. Is set to "1", and if not detected, "0" is set).

Here, when the detection operation of the reference marks 10 and 11 is performed for each scanning line as described above, four states as shown in FIG. 10 occur for each scanning line.

That is, state 1 is a state in which neither the start reference mark 10 nor the stop reference mark 11 has been detected in one scanning line, and is represented by (0, 0) on the reference mark detection register 45. .

State 2 is a state in which only one of the start reference mark 10 and the stop reference mark 11 is detected in one scanning line, and is (0, 1) or (1, 0) on the register 45. expressed.

State 3 is a state in which both the start reference mark 10 and the stop reference mark 11 have been detected in one scanning line.
It is represented by 1).

State 4 is a state in which only one of the start reference mark 10 and the stop reference mark 11 is detected in one scanning line, as in state 2, and (0, 1) or (1,
0). However, the difference between the state 4 and the state 2 is that the state 2 detects the upper part of the reference mark 10 or 11, while the state 4 is the reference mark 10 or 11.
Is that the lower part of is detected.

Whether or not the document is tilted, and the direction of tilt when the document is tilted, can be known by observing the transition process between the above four states.

That is, when the mark sheet 12 is scanned in a state where the mark sheet 12 is not inclined at all, the state 2 and the state 4
Does not occur.

When the mark sheet 12 is scanned in an inclined state, the state changes from state 1 to state 2 to state 3 to state 4. More specifically, when the mark sheet 12 is scanned while being tilted to the right, (0,
0) → (1,0) → (1,1) → (0,1) → (0,
0) and the state transitions. Further, when the mark sheet 12 is scanned while being tilted to the left, (0, 0) →
The state changes in the order of (0,1) → (1,1) → (1,0) → (0,0).

If the state 2 is followed by the state 4 without passing through the state 3, or the state 4 is followed by the state 3 without passing through the state 1, the mark sheet 12 is extremely inclined. Means that scanning was performed. In this embodiment, in such a case, the abnormal processing is executed without correcting the inclination of the scanning line described later. In other words, if the mark sheet 12 is extremely tilted so as to be uncorrectable, an abnormal process different from the tilt correction is performed, and some action is immediately performed (for example, the mark sheet 12 is read again). .

Further, the state changes from the state 3 or the state 4 to the state 1 at the end of each line of the mark entry section 8 except when the mark sheet 12 is abnormally greatly inclined. Therefore, in this embodiment, when such a transition occurs, it is regarded that one line of the mark entry column 8 has been completed, and
Executes row data processing which will be described in detail later.

FIGS. 11 and 12 show state transition diagrams and state transition tables between the above-described states. In FIG. 12,
The “state” column shows the state of the previous scanning line, while the “input” column shows the state of the next scanning line.

Based on the above, in this embodiment, the mark detection processing on the mark entry column 8 is performed while referring to the reference mark detection register 45 which of the four states corresponds to each scanning line. I do. Next, this will be described with reference to FIGS.

First, in the scanning line in the state 1, since the image signal corresponding to the mark entry column 8 is not included at all,
Do not execute mark detection processing.

In the scanning line in the state 2, the reference position is known from one of the detected reference marks, and the scanning line is moved from the reference position to the horizontal interval of the mark entry column 8 registered in the ROM 20 in advance. The black pixel counting circuit 31 counts the number of black pixels included in a portion corresponding to the mark entry column 8 in the divided section. That is, in the present embodiment, the black and white determination of the image signal is performed only in the section based on the space between the horizontal directions of the mark entry fields 8 registered in the ROM 20 in advance.

For example, when the start reference mark 10 is detected, that is, in the case of (1, 0), the scanning line is started from the position based on the reference position information saved in the start reference mark position register 46. Is divided every 4mm,
Further, the black pixel counting circuit 31 counts the number of black pixels included in each portion corresponding to the mark entry column 8 in the divided 4 mm section. As described above, since the number of black pixels is counted only in the portion corresponding to the mark entry column 8, the processing speed is remarkably improved.

Here, in the black pixel counting 31, the counting of the previous black pixel is specifically performed as follows (the timing chart is shown in FIG. 8).

That is, the microprocessor 19 sends the starting pulse r to the parallel / serial conversion register 33 and the 1 / 8-minute period 32, and at the same time, the mark entry field 8
Are output in parallel from the RAM 35 to the register 33 via the data bus. 1/8 minute cycle 3
2 receives the start signal r, supplies a data shift pulse u to the register 33, and causes the register 33 to serially output the image signal to the integrating counter 34, and at the same time, the image signal is stored in the integrating counter 34 for 8 pixels. During the input, the integration section signal s is output, and during that time, the integration counter 34 is set to the operating state. Thereby, the integration counter 34
Counts the number of black pixels in the section corresponding to each mark entry column 8.

On the other hand, the eight line registers 52 (1) to 52 (8) on the work area 40 of the RAM each have a capacity of 40 bits corresponding to the number 40 of the mark entry columns 8 in one row. .

If it is assumed that processing is performed for the scanning line in the second state for the first time, the microprocessor 19 transmits the count result of the integrating counter 34 corresponding to each mark entry column 8 through the data bus 21. type in,
If the count result is greater than or equal to the threshold value S1, the corresponding bit of the first line register 52 (1) is set to "1", while the count result is equal to the threshold value S1. Is set to 2.

Next, similarly, the microprocessor 1
9 also shows the second scanning line in the second state.
The count result of the number of black pixels in the section corresponding to each mark entry column 8 is compared with the threshold value S1, and according to the comparison result, the corresponding bit of the second line register 52 (2) is set to “1”.
Alternatively, "0" is set, and the same applies to the third and subsequent scanning lines in the second state, and "1" is set to the corresponding bit of the corresponding line register 52 (3) to 52 (8). Or, set “0”.

Here, in this embodiment, the number of line registers 52 is set to eight for the following reason.

The number of scanning lines that are continuously in the state 2 depends on the inclination angle of the mark sheet 12, and the maximum number of scanning lines K is determined by the maximum allowable inclination angle θ of the mark sheet 12. In the present embodiment, from state 2 to state 4 through state 3
Therefore, the distance L between the reference marks 10 and 11 located on both sides of the mark entry column 8 of one line is assumed.
1, assuming that the vertical length of the reference marks 10 and 11 is L2, the maximum allowable inclination angle θ is θ = arctan (L2 / L1).

Assuming that L1 = 160 mm and L2 = 4 mm, θ
≒ 1.4 °. Then, the maximum number of scanning lines K at this time is
Is K = L2 / D, where D is the pixel density.

Therefore, if D = 0.5 (2 lines / mm), K = 8. Therefore, in this embodiment, the number of line registers 52 is eight.

In this embodiment, the number of the scanning lines which are continuously in the state 2 is sequentially counted by the inclination counter 51. The total number indicates the inclination angle of the mark sheet 12 as described above.

Also, as described above, the line register 5
2 (1) to 52 (8), the data relating to the one-line mark entry column 8 for state 2 is stored in state 2 to state 3
The process is performed as follows when transitioning to.

First, the line registers 52 (1) to 52 (52)
All data stored in (8) is stored in the tilt counter 51.
Are separated into valid data and invalid data according to the content of That is, according to the contents of the tilt counter 51, FIG.
Is separated from the effective slope (the shaded area) and the other invalid area, and the data in the effective area is regarded as valid data.

On the other hand, the same number (40) of the bit counters 53 as the number of the mark entry columns 8 for one line are prepared, and each bit counter 53 corresponds to one of the mark entry columns 8 for one line. Then, these bit counters 53 (1) to 53 (4
Using (0), the number of "1" s set in the line registers 52 (1) to 52 (8) as valid data is counted for each mark entry column 8 of one line.

Next, the following processing is performed on the scanning line in the state 3. First, as in the case of the scanning line in the state 2, the black pixel counting circuit 31
The number of black pixels in the section corresponding to each mark entry column 8 of the row is counted. The section corresponding to each of the mark entry columns 8 is determined based on the reference position information of the two references 10 and 11 saved in the reference mark position registers 46 and 47.

However, in state 3, since all the image signals are included in the effective area as shown in FIG. 13, unlike the processing for the scanning lines in state 2, the bit register 52 (1) to 52 (8) are not operated. Then, the counting result of the black pixel counting circuit 31 for the section corresponding to each mark entry column 8 is compared with the threshold value S1,
If S1 or more, the corresponding bit counter 5
While 3 is incremented by 1, if it is smaller than S1, the corresponding bit counter 53 is held as it is.

Next, for the scanning line in the state 4, the same processing as the processing for the scanning line in the state 2 is performed.

On the other hand, the start reference mark lengthwise counter 4
Reference numeral 9 denotes the number of scanning lines that have detected the start reference mark 10 until there is a transition from “state 3 → state 1” or “state 4 → state 1” (that is, until one line of the mark entry column 8 ends). Is counted. Similarly, the stop reference mark vertical counter 50 indicates “state 3 → state 1” or “state 4”.
-> Stop reference mark 11
Is counted.

If the counting results of the two vertical counters 49 and 50 are not within the predetermined range determined based on the vertical length of the reference marks 10 and 11, the corresponding mark entry field 8
The row data processing described below is not performed for the row of. Thereby, the reference mark 1 is added to the mark sheet 12.
The reference marks 10, 1 have the same or similar width as 0, 11 but have different vertical lengths even if there are marks or stains.
There is no risk of being mistaken as 1.

The row data processing is executed after the transition from “state 3 → state 1” or “state 4 → state 1” and after checking the counting results of the portrait counters 49 and 50. Is done. This row data processing is performed in state 2, state 3
And the final values of the bit counters 53 (1) to 53 (40) that have performed the counting through state 4 are compared with a threshold value S 2, and “1” if the value is greater than or equal to S 2, and “0” if smaller than S 2. , Output buffer area 39 of RAM 35
The content is to be set to the corresponding bit of Here, "1" means that it is determined that a mark has been written in the mark writing column 8, and "0" means that it has been determined that no mark has been written. In the present embodiment, the threshold value S2 is set to 4.

The above operation is repeated for each line of the mark entry column 8, and the mark detection results for each line are sequentially stored in the output buffer area 39.

When the scanning start signal p becomes "0", the above operation is completed, and the mark detection result for each mark entry column 8 stored in the output buffer area 39 is output to the external data processing device through the output circuit 36. (Not shown). The output circuit 36 outputs a control signal for interfacing with the data processing device, in addition to the mark detection result. However, the output circuit 36 is a part designed according to the data processing device. Therefore, detailed description is omitted.

As described above, in the present embodiment, the inclination angle of the mark sheet 12 and the inclination direction of the mark sheet 12 are monitored based on the four states represented by the presence or absence of the detection of the pair of left and right reference marks 10 and 11. Since it is detected whether or not a mark is written in the mark sheet 8, the mark sheet 12
Even if the tilt angle changes between the start of scanning and the end of scanning, the tilt angle can be properly compensated and extremely accurate mark reading can be performed.

When a facsimile apparatus is used as a reading apparatus, the mark detection circuit shown in FIG. 4 may be connected to a facsimile transmitting apparatus or a facsimile receiving apparatus.

Further, it goes without saying that the optical reading device according to the present invention is not limited to a facsimile device.

Further, in the above embodiment, the processing is performed assuming that only four states can occur as the detection state of the start reference mark and the stop reference mark in each scanning line. If the processing is performed assuming that a state where the start reference mark of a certain line and the stop reference mark 10 of the next line can be detected in the line, the mark can be detected with high accuracy even if the mark sheet is further inclined. .

[0078]

As is clear from the above description, the present invention
Is the mark entry field and the beginning and end of this mark entry field.
Mark with a pair of reference marks
Reading means for reading a sheet, and an input from the reading means.
Discriminates the black and white of the image signal to be
If a reference mark is detected, it is regarded as a reference mark,
Reference mark detecting means for detecting a mark,
The detection status of the fiducial mark is indicated according to the read transition of the
Register that stores the data to be stored, and the data in this register.
At least one of the fiducial marks based on the
Detect both reference marks from the state where one is detected
When the status changes to No,
Line data processing to determine whether or not
Is repeatedly executed for each of a plurality of lines in the mark entry field.
With the provision of the control means, it is not necessary to temporarily store all the image information on the mark sheet in the memory, so that a large capacity memory is not required. Further, when a transition is made to a state in which both of the reference marks are not detected, it is determined whether or not the mark has been written, so that the determination process can be performed in a short processing time.

[Brief description of the drawings]

FIG. 1 is a front view of an example of a conventional mark sheet.

FIG. 2 is a front view of another example of a conventional mark sheet.

FIG. 3 is a front view of a mark sheet used in the mark reading device according to the present invention.

FIG. 4 is a block diagram of a mark detection circuit according to the present invention.

FIG. 5 is a map diagram of a RAM 35 in the mark detection circuit.

FIG. 6 is a diagram showing allocation in a work area 40 of a RAM 35;

FIG. 7 is a timing chart of the image input circuit 24 in the mark detection circuit.

FIG. 8 is a timing chart of the black pixel counting circuit 31 in the mark detection circuit.

FIG. 9 is a timing chart showing a reference mark detection operation in a limited section search mode in the mark detection circuit.

FIG. 10 is an explanatory diagram showing four states depending on the presence or absence of detection of a start reference mark and a stop reference mark in one embodiment of the present invention.

FIG. 11 is a state transition diagram between the four states.

FIG. 12 is a diagram showing a state transition between the four states.

FIG. 13 is an explanatory diagram showing an effective area in a scanning line corresponding to the state 2;

FIG. 14 is an operation flowchart in one embodiment of the present invention.

FIG. 15 is an operation flowchart in one embodiment of the present invention.

FIG. 16 is an operation flowchart in one embodiment of the present invention.

[Explanation of symbols]

 1 Mark entry column 9 Article column 10 Start reference mark 11 Stop reference mark 12 Mark sheet 19 Microprocessor 24 Image signal input circuit 31 Black pixel counting circuit 36 Output circuit

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-50480 (JP, A) JP-A-55-41591 (JP, A) JP-A-55-25127 (JP, A)

Claims (1)

(57) [Claims] 1. A mark entry field and the beginning of the mark entry field
A pair of fiducial marks indicating the end
Reading means for reading the mark sheet,
Discriminate black and white of the image signal input from the
Is detected as a reference mark when a black signal
Fiducial mark detecting means for detecting a fiducial mark;
Detection of the fiducial mark in response to the read transition of the worksheet
A register for storing data indicating a state, and the register
At least one of the fiducial marks based on the data in
In the state where either one is detected,
When a transition is made to a state where no
Line for determining whether or not a mark is entered in each column
Data processing is repeated for each of a plurality of lines in the mark entry column
And a control unit for executing the mark reading.