JPH0557632B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical character input device used, for example, in a character recognition device.

[Technical background of the invention and its problems]

Conventionally, optical character reading devices (OCR) generally read documents in which characters are recorded with relatively small inclinations of character lines and constant line spacing. This is because character recognition processing detects and extracts each character from a group of characters in a document.
This is because this detection cutting process requires reliable detection of the position of the character line.

Specifically, for example, in a document 10 as shown in FIG. Histogram 1 as shown in b
Create 2. Then, the histogram 12 is sliced at a predetermined level 13 and converted into a binary signal 14, and the position of a character line is detected using this binary signal 14. From this detected character line, characters are detected and extracted by the detection extraction process as described above.
It will be recognized by the character recognition unit.

Incidentally, in recent years, OCR has been developed to enable reading processing of documents with a high degree of freedom in format. Here, a document with a high degree of freedom in format means, for example, as shown in FIG. 2, a character line 21 is printed with a different format such as line spacing, line skew, character size, and font for a predetermined character line 20. This is document 22. OCR using the conventional method is applied to such documents 22.
In this case, it is difficult to accurately detect each character line, and therefore, character reading processing is also impossible.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and
The purpose is to provide an optical character input device that can reliably read characters recorded on a document even when the document has a relatively flexible format.

[Summary of the invention]

In the present invention, a pattern buffer memory is provided for storing a binary pattern signal obtained after photoelectrically converting characters recorded on paper. The trajectory pattern creation means creates a trajectory pattern obtained by parallelly moving the binarized pattern signal. The trajectory pattern created by this trajectory pattern creation means is stored in a trajectory pattern buffer memory. The detection means scans the locus pattern buffer memory to detect the outline of the character line. Based on the contour point coordinate information of the character line which is the result of this detection, the detection and cutting means is configured to detect and cut out the character pattern of each character from the binary pattern signal in the pattern buffer memory.

As a result, even in the case of a document including character lines with different formats such as line spacing, the positions of the character lines can be reliably detected. Then, based on the detection result of the character line, the character pattern of each character can be reliably detected and cut out.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of an optical character input device according to one embodiment. In FIG. 3, a photoelectric conversion unit 30 photoelectrically converts characters on a document, converts the electrical signal obtained by the photoelectric conversion into a binary pattern signal (hereinafter referred to as a binary signal) P, and outputs the signal. The video buffer 31 includes a photoelectric conversion section 30
Normally, one page's worth of binary pattern signals P output from the memory are stored. The counter 32 is a periodic counter (for example, Texas Instruments SN74ALS16IN).
is counted up by the scanning clock when the binary signal P is output from the photoelectric conversion unit 30, and is counted up by 2.
When the digitized signal P is at the black level, the value "0" is loaded. The comparator 33 compares a preset constant value B and the output value A of the counter 32, and outputs an output Q to the locus pattern buffer 34 if the constant value B is larger. The trajectory pattern buffer 34 generates a trajectory pattern (FIG. 4b) obtained by parallelly moving the output Q from the comparator 33, that is, the binary signal P (FIG. 4a) by a certain distance (corresponding to a constant value B). Store.

The counter 35 counts the number of black bits of the trajectory pattern output from the comparator 33 in one scanning period, and outputs a projection histogram which is the count output to the projection buffer 36. On the other hand, when the binary signal P is stored in the video buffer 31, the write controller 37 controls the photoelectric conversion unit 30, the video buffer 31, the trajectory pattern buffer 34, the projection buffer 36, and each counter 32,
35 operations. Further, the readout controller 38 controls the operations of the video buffer 31, the trajectory pattern buffer 34, and the projection buffer 36 when a character pattern for each character is detected and cut out from the video buffer 31.

The operation of one embodiment of the optical character input device configured as described above will be described. Suppose now that a document 52 as shown in FIG. On the other hand, based on the binary signal P, by the operations of the counter 32 and the comparator 33 as described above, a locus pattern Q corresponding to each character line as shown in FIG. is stored in The trajectory pattern Q created as described above is supplied to the counter 35. The counter 35 counts the number of black bits of the locus pattern output from the comparator 33 during one scanning period as described above. A projection histogram (53 in FIG. 5b) which is the count output is stored in the projection buffer 36.

In this way, the binary pattern signal P for one page on the paper is written to the video buffer 31,
Further, a locus pattern Q corresponding to the binary pattern signal P is written into the locus pattern buffer 34.
When this writing operation is completed, an operation for detecting the outline of a character line is executed.

That is, the read controller 38 first searches the projection buffer 36 and obtains the projection histogram 53.
Find the character line detection starting point X ₀ based on . Furthermore, the readout controller 38 reads the obtained detection viewpoint.
Based _on
Find X ₁ ) in the figure. The contour of the locus pattern Q is traced from this tracing start point coordinate _X1 , and a contour point coordinate series corresponding to the contour of the locus pattern Q is determined. In this case, when the tracking started from the tracking start point coordinates _X1 returns to the tracking start point coordinates _X1 , the tracking operation stops.
As a result, a contour coordinate point sequence that determines the contour of each character line shown in FIG. 5a is obtained. Based on this contour point coordinate series, the 2 points stored in the video buffer 31 are
A binarized pattern signal P for each character line is determined from the digitized pattern signal P. Hereinafter, character pattern detection processing for each character will be performed on the binary pattern signal P for each character line. Here, in tracking the next trajectory pattern, the next starting point _X2 is detected by scanning horizontally while avoiding the trajectory pattern that has already been detected. Thereafter, the trajectory pattern tracking operation is repeated in the same manner.

Next, from the contour point coordinate series obtained as described above, a character detection scan starting point Y as shown in FIG. 7a, for example, is determined by the readout controller 38. Then, based on the found starting point Y,
For the binarized signal P in the video buffer 31,
As shown in FIG. 7b, the vertical scanning is performed so as to be shifted to the right. As a result, character patterns for each character are detected and cut out. In addition, in the operation of creating the trajectory pattern as described above, the binary signal P was created by moving a certain distance in one direction.
It may be created by moving in both directions.

As described above, a locus pattern Q corresponding to each character line recorded on the document is created, and the outline of the character line is detected based on this locus pattern Q. Based on this detected contour (contour point coordinate series),
Character patterns for each character are detected and cut out from the binary signal P stored in the video buffer 31. Therefore, even in the case of a document containing a mixture of character lines with different formats such as line spacing, line skew, character size, and font, each character line can be detected reliably, and the character pattern of each character can be detected and cut out. can be released.

〔Effect of the invention〕

As detailed above, according to the present invention, even in the case of a document with a relatively flexible format in which character lines with different line spacing etc. coexist, each character line can be detected and each character can be reliably identified. Can be read and processed. Therefore, when applied to OCR, characters in a document can be reliably recognized, and it can also be applied as an input device for transcription or transcription equipment that re-edits image data in character line units. .

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the operation of conventional OCR. Figure a shows a document, Figure b shows a histogram, Figure 2 shows an example of a document in a highly flexible format, and Figure 3 shows an example of a document with a highly flexible format. The figure is a block diagram showing the configuration of an optical character input device according to an embodiment of the present invention.
4 is a diagram for explaining the operation of the apparatus shown in FIG. 3, in which a shows a binary pattern signal, b shows an example of a locus pattern, and FIG. This figure is for explaining the operation of the device.
Figure 6b shows an example of a projection histogram.
The figure is a diagram for explaining the operation for detecting the outline of a character line in the apparatus of Figure 3, and Figure 7 is a diagram for explaining the operation for detecting the outline of a character line in the apparatus of Figure 3.
FIG. 2 is a diagram for explaining the detection and extraction operation in the apparatus shown in the figure, in which FIG. 30...Photoelectric conversion unit, 31...Video buffer, 32, 35...Counter, 33...Comparator, 34...Trajectory pattern buffer, 36...
Projection buffer, 37...Write controller, 3
8...read controller.

Claims (1)

[Scope of Claims] 1. Photoelectric conversion means for outputting a binary pattern signal obtained by photoelectrically converting characters recorded on paper, and storing the binary pattern signal output from this photoelectric conversion means. a pattern buffer memory for translating the binarized pattern signal outputted from the photoelectric conversion means, a trajectory pattern creation means for creating a trajectory pattern obtained by parallelly moving the binarized pattern signal output from the photoelectric conversion means, and the trajectory created by the trajectory pattern creation device. a locus pattern buffer memory for storing patterns, and scanning the locus pattern buffer memory to trace the contour of the locus pattern to obtain contour point coordinate information corresponding to the character portion recorded on the paper. a detection means for detecting the contour of a character block; and a detection means for extracting a character block pattern corresponding to the locus pattern from the pattern buffer memory based on the contour point coordinate information obtained by the detection means; 1. An optical character input device comprising: detection and cutting means for detecting and cutting out a character pattern for each character from a character pattern.