JPS5943795B2 - First detection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stroke order detection circuit for character lines (strokes) of characters used in character reading devices.

In recent years, character reading devices have begun to be used for input into electronic computers, and their importance has increased due to their ability to save labor, and even devices that can read handwritten kana characters are becoming commercially available.

However, when reading kana characters, for example, misreading may occur between ``so'' and ``n''. Although these characters have almost no difference in appearance, humans distinguish them by observing the stroke order by changes in the thickness of the strokes and subtle changes in density. However, since machines usually digitize character signals and process binary signals, information about thickness and density is lost, resulting in people misreading G as N, or misreading N as G. It is easy to misread it. Therefore, an object of the present invention is to provide a stroke order detection circuit that determines the order of strokes by examining changes in thickness and density around the ends (end points) of strokes of characters, etc., in order to bring machines closer to human abilities. There is a particular thing. In the present invention, in distinguishing between ``G'' and ``G,'' the detection of downward-left and downward-rightward strokes is performed by comparing the darkness and thickness of the characters at both ends of the stroke.
Generally, the edges that are written first will be the darker or thicker parts,
It takes advantage of the fact that the edge that is flipped becomes a pale or thin part. If the stroke order detection circuit according to the present invention is used in combination with a conventional character reading device, it is possible to correctly read character strokes that could not be distinguished without distinguishing the stroke order.
Extremely useful.

The present invention will now be described in detail with reference to drawings of embodiments of the invention.

FIG. 1 is a diagram showing an embodiment of the present invention, which is similar to the "downward left stroke" that appears in the character "S" in FIG. It is used to distinguish between "upward right strokes" as shown in the characters .

When photoelectrically converting characters, etc., the character signal is obtained by scanning from the top right downwards and then sequentially to the left as shown in Figure 2. Figure 1 shows the scanning shown in Figure 2. It is configured in accordance with the direction of Of course, the direction of scan can be changed, and the change can be accomplished by simply changing the interconnections of the circuit components to correspond to the scan direction. Now, in FIG. 1, character signal 1 and character signal 2 are led to the inputs of multiple shift register 30 and OR circuit 31.

Character signals 1 and 2 have a 2-bit gray level; for example, character scanning signals in a conventional character reading device are
It can be obtained by passing two thresholds. Character signals 1 and 2 are divided into three levels depending on the darkness of the characters.
The value of character signal 1|2 is ``00'', which indicates the background, that is, the level of the paper surface, etc.;
"11" is a value that makes the characters gradually darker. Therefore, the slice output 311 of the OR circuit 31 indicates that some character signal is present at the input when the logic value is "1", and indicates that it is a background signal when the logic value is "0". It has become one input. The shift pulse 3 is a pulse given in synchronization with the character signals 1 and 2 from a scanner (not shown) that scans characters, etc. of a character reading device using the stroke order detection circuit according to the present invention, and is a pulse that is synchronized with the sample pulse of the character signal. Since they have the same period, further explanation will be omitted here as they are treated as external conditions given by the scanner. Scanning of characters, etc. is 64 times vertically
It is divided into meshes and scanned.

In this example, 1 mesh is 0.15 x 0.15
The number of scan lines for one character is 32. Since one mesh is scanned at 1 μs, one scan takes 64 μs, and 2048 μs for one character.
It takes.

The multiplex shift register 30 has 64 bits in the vertical direction, and converts the 2-bit character signal given by the gray level for one scan into two characters.
It is configured to store in column shift registers. The multiple shift register 30 as a whole temporarily stores character partial patterns for 10 scans in 20 columns of shift registers. In the shift register 30, the leftmost two columns of outputs X,
y is led to the inputs at the bottom of the two columns on the right, and the shift is performed from bottom to top and from left to right by shift pulse 3. Therefore, the character pattern is shifted in the form of an erect image on the diagram in relation to the scanning direction. The sub-molecules of the multiplex shift register 30 define areas for detecting the end points of the strokes of the character pattern being shifted and measuring the density around the end points, and a plurality of outputs 300 are led to the inputs of the density measurement circuit 32. ing. Details of the submolecules will be described later. Output 32 of concentration measuring section 32
0 is a 7-bit signal and is led to the respective inputs of the P register 34 and Q register 35.

On the other hand, a lower end point detection pulse 331 and an upper end point detection pulse 332 are outputted from an end point detection circuit 33, the details of which will be described later, and are led to set inputs of a P register 34 and a Q register 35, respectively. Therefore, the P register 34 stores the density of the stroke around the end point when the lower end point is detected, and the Q register 35 stores the density of the stroke around the end point when the upper end point is detected. Output 3 of P register 34
40 is led to one input of the comparator 36 and the subtraction circuit 37, and the output 350 of the Q register 35 is led to another input of the comparator 36 and the subtraction circuit 37. The output 361 of the comparator 36 is configured such that the inside of the Q register is larger than the inside of the P register. Output 361 is led to one input of AND circuit 41 and to the input of NOT circuit 38 . It is clear that the output 381 of the NOT circuit 38 becomes "1" when the contents of the Q register are less than the contents of the P register.
It is led to one input of AND circuit 42. The subtraction circuit 37 calculates the difference between the contents of the P register and the Q register, and its output 370 serves as one input of the comparator 39. The output 400 of the comparison data register 40 storing comparison data is applied to the comparator 39 as the other input. The comparison data here is used to specify that the difference in density between the "start of stroke" and "end of stroke - 1" is greater than a certain value, in order to determine the accuracy of stroke order. is generally determined based on the size of the character, scanning resolution, etc., but in this embodiment, the number of target meshes of the submolecules used when detecting end points, especially black parts such as characters, is 28, which is 28. It is set to 1/4 of 7.Therefore, the contents of the comparison data register 40 are semi-fixed to 7.Of course, this value is not absolute and can be changed depending on the situation. The output 391 of the comparator 39 becomes "1" when the difference in density between the two end points is greater than the comparison data, and is led to the other inputs of the AND circuits 41 and 42, respectively. There is.

Thus, the output 411 of the AND circuit 41 becomes 1" when the content of the Q register is larger than the content of the P register and satisfies the density difference regulation, that is, the output 411 of the "downward left stroke". The output 421 of 42 is the output 421 when the content of the Q register is less than the content of the P register and satisfies the density difference specification, that is, the output 421 of the ``rightward upward stroke''.

In other words, the stroke order is determined. Next, the end point detection section is constructed as shown in FIG.

The slice output 311 is led to the input of the first lower left pit of the shift register 92, and is sequentially shifted upward by the shift pulse 3 to the output 6 of the uppermost bit of the leftmost column.
41 to the input of the lower end bit of the second column on the left. The following connections are made in the same way. The shift register 92 is composed of 10 columns of 64 bits in the vertical direction, and temporarily stores character signals sliced at level "011".

Particularly in the shift register 92, symbols are attached to locations corresponding to the partial molecules shown in FIG. 1, and these indicate the names of the output signals of the corresponding bits.

The bit outputs a-M and A-M are negative outputs and specify that they should all be 11'' when detecting an end point, that is, that the background around the stroke is white.

Further, bit outputs 01 to 28 indicate the black portion, that is, the character portion, and should be 61°, satisfying a certain condition described later.

Furthermore, bit outputs P-T and V-Z are used to specify the conditions for detecting the "upper end point" or "lower end point". Bits marked with an alphanumeric character are negative outputs, and bits marked with a number are positive outputs. Among the outputs of each bit of the shift register 92, bit output 03,
Bit outputs 08, 13, 18, and 23 are input to the OR circuit 72, bit outputs 04, 09, 14, 19, and 24 are input to the OR circuit 73, and bit outputs 05, 10, 15, 20, and 25 are input to the OR circuit 74. Input bit output 06, 11, 16, 2
1 and 26 are respectively led to inputs of an OR circuit 75. The output 721 of the OR circuit 72 is output from the shift register 92.
Look sideways at the 5-bit part of bit output 03-23 and write “
When the black signal is present, the output 731 of the OR circuit 73 becomes 81".
is 1° when there is a black signal in the 5-bit portion of bit outputs 04 to 24, and the output 741 of the OR circuit 74 is
"Black signal present" in 5-bit part of bit output 05 to 25
The output 751 of the OR circuit 75 becomes "1" when there is a "black signal present" in bit outputs 06 to 26 (5 bits), and these four signals are output to the AND circuit 76. are respectively led to the inputs.Therefore, the AND circuit 76
The output 761 becomes 1 when there is a cluster of black signals in the center area of the black part.

The output 761 is led to one of the inputs of the AND circuits 90 and 91, and serves as one condition for end point detection. The bit outputs a-M, A-M (26 bits) of the shift register 92 are led to the input of an AND circuit 77.

Since the bit outputs a-M and AM have negative outputs, the output J/V1 of the AND circuit 77 becomes 1 when both sides of the black part are white parts. In other words, the output Jmo V1 serves as a condition for defining the white portion on both sides of the stroke around the end point, and serves as another input to the AND circuits 90 and 91. Next, the bit outputs 01 to 06 of the shift register 92
(6 bits) is led to the input of the OR circuit 88.

The output 881 of the OR circuit 88 becomes 61゛ when the black part exists in contact with the white part in the upper left corner, and end point detection occurs only once for each end point while the character pattern is being shifted through the shift register 92. This is one of the other inputs of the AND circuits 90 and 91. Bit output P-T (5 bits) of shift register 92 is led to an input from AND circuit 87.

Since the bit output PT is a negative output, the AND circuit 8
The output 871 of 7 becomes "1" when a white part is below the black part detection, and is led to another input of the AND circuit 90 as one condition for "lower end point" detection. On the other hand, using the same idea, the output bit V- of the shift register 92
Z (5 bits) is led to an input of an AND circuit 89, and its output 891 is led to another input of an AND circuit 91 as one condition for detecting the "upper end point".
Next, the bit outputs 01, 12, 23 of the shift register 92
is led to the input of the OR circuit 85.

The output 851 of the OR circuit 85 becomes 1 when there is a black signal in contact with the part defining the upper white part of the stroke, which is one of the conditions for detecting the "upper end point", and the output 851 of the AND circuit 91 becomes 1.
is guided by one other input. On the other hand, using the same idea, bit outputs 06, 17, 2 of the shift register 92
8 is led to the input of the OR circuit 86, and "lower end 7
(5) This is one condition for detection and is led to another input of the AND circuit 90. AND circuits 90 and 91
The last input of is for detecting the end point with higher accuracy, and the output 841 of the OR circuit 84 and the output 711 of the OR circuit 71 are respectively led thereto.

More specifically, for the series of OR circuits 84, the bit outputs 05, 11, 06, 16, 22 of the shift register 92
, 17, 27, 28, as shown in the figure, a signal for checking the black part of the lower end point, that is, the continuity of the stroke, is generated by a combination of OR circuits 78, 80, 82 and AND circuits 79, 81, 83. I'm making it. Next, regarding the series of OR circuits 71, the bit outputs 02, 07 of the shift register 92
, 01, 13, 18, 24, 23, as shown in the figure, OR circuits 65, 67, 69 and AND circuits 66,
The combination of 68 and 70 creates a signal that confirms the black part of the [upper end point], that is, the continuity of the stroke. As described above, when all the input signals of the AND circuit 90 satisfy the end point detection conditions, the output becomes "1" and the "lower end point" detection pulse 331 is detected. In addition, when all the input signals of the AND circuit 91 satisfy the end point detection conditions, the output becomes 1.
At the upper end, a direction detection pulse 332 is output. Next, the concentration measuring section is constructed as shown in FIG.

FIG. 4 again shows the multiple shift register 30 shown in FIG. The multiplex shift register 30 is composed of 10 sets of shift registers in two columns, and 64 bits are arranged in the vertical direction. Among these, for the same area as the black part, that is, the bit output 01 to 28 (28 bits) defined when detecting the end point in Fig. 3, in Fig. 4, the output (AOl, BOl) - (A28,B
28) are defined, and using these data, the density of the entire black portion including its thickness is measured by the density measuring circuit 32. Output (AOl, BOl)
~(A28, B28) is 28 that varies in the range of values 0 to 3
All of the data in the set are expressed in 2-bit binary numbers.

Since the operation of the multiple shift register 30 has been described above, the output 300 (
28×2=56) are led to the input of the concentration measuring circuit 32, and are added by an adder to obtain the concentration data output 320. First, the multiple shift register 30
Of the output 300, the outputs AOl, BOl, AO2, BO
2 is led to the input of the 2-bit adder 500, and the addition result is output to the 3-bit addition output 509. Similarly, outputs AO3, BO3, AO4, BO4 to output A27
, B27, A28, B28, two sets of 2-bit data are stored in 13 adder circuits 510, 520, . . . , 630.
and 13 addition outputs 519, 529,
. . , 639 are obtained, and together with the addition output 509, 14 sets of 3-bit intermediate data are obtained. Then 3 bits 14
Two sets of data are sent to seven 3-bit adders 700.
, 710, . . . , 760, and outputs 709, 719, . . . , 769 are obtained as addition results.

Next, the adder 800 whose outputs 709 and 719 are 4 bits,
Outputs 729 and 739 are led to the respective inputs of a 4-bit adder 810, and outputs 729 and 759 are led to the respective inputs of a 4-bit adder 820. Next, the output 80 of the adder 800
9 and the output 819 of the adder 810 are the 5-bit adder 9
0 input, the output 829 of adder 820 and adder 760
The output 769 is led to the input of a 5-bit adder 91.

Finally, the output 909 of adder 90 and the output 91 of adder 91
A zero is led to the input of a 6-bit adder 1000, yielding a 7-bit concentration measurement output 320. The measurement results will vary from a minimum of 6 (6 meshes for the value "0") to a maximum of 84 (28 meshes for the value "11") when detecting the end point.

As described above, as shown in FIG.
, Q register and the subsequent stroke order determining units can form a stroke order detection circuit.

When a character signal as shown in FIG. 2a is input, the "left downward" detection output 411 in FIG. 1 becomes ``1'''', and when a character signal as shown in FIG. 2b is input, If the "downward to the right" detection output 421 in FIG. 1 becomes "1" and these signals are obtained, it means that the stroke order has been determined. In the embodiment of the present invention described above, the gray level of the character signal is expressed by 2 bits, but it is possible to increase or decrease this according to the required precision. It is also possible to make the end point detection conditions stricter or looser. Furthermore, it is clear that by changing the shapes of the molecules in FIG. 1 to match the inclinations of various strokes, it is possible to obtain a circuit for determining the stroke order of various strokes.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing an example of an input character pattern, FIG. 3 is a detailed diagram of an end point detection circuit, and FIG. 4 is a diagram of a density detection circuit. It is a detailed view. In the figure, 30...multiple shift registers, 3
1...OR circuit, 32...Concentration measurement circuit, 33...End point detection circuit, 34, 35...
...Register, 36, 39...Comparator, 37
...Subtraction circuit, 38 ...Negation circuit, 4
0... Comparison data register, 41, 42...
...AND circuit, 92...shift register,
90,91,500,510,620,630,700
,720,r30,740,750,760,800,
810, 820, 1000... Adder.

Claims (1)

[Claims] 1. An end point detection unit that detects the end point of a character stroke;
A density measurement unit that measures at least one of the thickness and density of the stroke around the end point, and the density difference around both ends of the stroke of the character to determine the stroke order from the end with higher density to the end with lower density. A stroke order detection circuit comprising a stroke order determining section.