Apparatus and method for recognizing characters

An apparatus and method for recognizing characters in image information includes inputting image coordinate data corresponding to the handwritten image, displaying a calligraphic image on the basis of the image coordinate data, recognizing characters in the image coordinate data, and erasing the calligraphic image and displaying recognized characters recognized in the recognizing step in the event that a recognized character is a predetermined character such as a period (".").

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus and method for recognizing 
handwritten characters which are input in real time and for displaying the 
result of the recognition. 
2. Description of the Related Art 
Hitherto, there has been a system for recognizing handwritten characters 
which accepts input handwritten character information as one character 
unit when handwritten character information is input. For example, in 
coordinate input devices such as a resistance film digitizer, character 
recognition is initiated upon activation of the recognition switch. 
In the prior art, there has been a system which performs an 
input/recognition/display operation repeatedly for each character. That 
is, the system performs recognition for one character of handwritten 
character information when the system recognizes that one character of 
handwritten character information is input and then displays the result of 
the recognition. 
However, the above-described prior art must be instructed as to when to 
initiate recognition of input handwritten characters, and this instruction 
is given by operating a switch each time a handwritten character is input. 
Thus, the inputting of character information is frequently stopped, 
thereby decreasing efficiency. 
In addition, in the above-described prior art, since trace information 
formed of coordinate data of input handwritten characters is displayed, 
the data of one input character is recognized when it is recognized that 
the inputting of one character of this handwritten character is finished, 
and the character pattern of the character obtained as a result of the 
recognition is changed to the input handwritten character data and 
displayed, inputting of handwritten characters is stopped because the 
display is changed frequently, which is inconvenient. 
SUMMARY OF THE INVENTION 
The present invention provides a method and apparatus for character 
recognition in which there is no need for frequent stopping of inputting 
handwritten characters; instead, operations for changing the display are 
collectively performed, thereby decreasing display screen flicker caused 
by display changing. 
According to one aspect of the present invention, a method and apparatus 
for recognizing characters in image information includes outputting a 
displayable image signal on the basis of the image information, 
recognizing character information on the basis of the image information, 
detecting whether recognized character information consists of specific 
character information, and outputting the result of character recognition 
in accordance with the result of the determining step. 
According to another aspect of the present invention, an apparatus and 
method for recognizing characters in image information includes inputting 
image coordinate data corresponding to the handwritten image, displaying a 
calligraphic image on the basis of the image coordinate data, recognizing 
characters in the image coordinate data, and erasing the calligraphic 
image and displaying recognized characters recognized in said recognizing 
step in the event that a recognized character is a punctuation mark such 
as a period ("."). 
Objectives and advantages in addition to those discussed above shall be 
apparent to those skilled in the art from the description of the preferred 
embodiment of the invention which follows. In the description, reference 
is made to the accompanying drawings, which form a part hereof, and which 
illustrate an example of the invention. Such example, however, is not 
exhaustive of the various embodiments of the invention, and therefore 
reference is made to the appended claims for determining the scope of the 
invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 is a view illustrating the construction of a character recognition 
apparatus according to an embodiment of the present invention. Reference 
numeral 1 denotes an input/output block which is formed of an input 
section 12, an input pen 11 and a liquid-crystal display section 13. 
Reference numeral 2 denotes a processing block which is formed of an input 
coordinate storage means 21, a handwritten character recognition means 22, 
a recognition result storage means 23, a sentence input processing 
continuation determination means 24, and a display control means 25. 
The input section 12 is an input panel in which electrodes are arrayed in 
the vertical and horizontal directions, and to which coordinate data is 
input when it is depressed with the input pen 11. Preferably, an input 
area 10 of the input section 12 is preallocated for inputting one 
character only. The coordinate data is sent to the input coordinate 
storage means 21. The input coordinate storage means 21 receives and 
stores the coordinate data of the input pen 11 sent from the input section 
12. The input character coordinate data is sent to the handwritten 
character recognition means 22 and the display control means 25. The 
handwritten character recognition means 22 recognizes characters on the 
basis of a conventional commonly-used recognition method, such as a 
pattern matching method, and sends code data of the recognized character 
to the recognition result storage means 23. The recognition result storage 
means 23 stores the code data of the recognized character sent from the 
handwritten character recognition means 22 and sends the character string 
data to the sentence input processing continuation determination means 24. 
The sentence input processing continuation determination means 24 sends a 
control code for clearing the display of the calligraphic input character 
and detecting the aforesaid character string code data from the display 
control means 25 when the sentence input processing continuation 
determination means 24 determines that inputting of one sentence is 
terminated on the basis of character string data sent from the recognition 
result storage means 23. The display control means 25 creates calligraphic 
display dot coordinate data on the basis of the input coordinate data sent 
from the input coordinate storage means 21, sends out data indicating that 
the liquid-crystal display section 13 should be cleared on the basis of a 
control code sent from the sentence input processing continuation 
determination means 24, and sends out the display dot coordinates of the 
character string data which are the result of the recognition obtained 
based on the character string data. The commonly used liquid-crystal 
display section 13 displays characters on the basis of the display dot 
coordinate data sent from the display control means 25. 
FIG. 2 is a block diagram of the embodiment of the present invention. 
Reference numeral 31 denotes a coordinate input section, which is an input 
panel having electrodes arrayed in the vertical and horizontal directions, 
and into which coordinate data is input when the input pen 11 is 
depressed. The coordinate data is sent to a central processing unit 32 
(hereinafter referred to as a CPU). The CPU 32 has a ROM 32a for storing 
programs by means of which operations are performed in accordance with the 
flowchart shown in FIG. 3, and a RAM 32b for storing data which must be 
processed. The CPU 32 stores coordinate values inputted from the 
coordinate input section in the RAM 32b by using the processing procedure 
stored in the ROM 32a, outputs the input coordinate values, performs a 
matching with a character pattern dictionary having coordinate values 
stored in a ROM, and outputs character codes as a result of the 
recognition. 
FIG. 3 is a flowchart which illustrates an operation sequence stored in the 
ROM 32a according to the present invention. FIG. 4 shows an example of 
characters input to the input section 12, which are displayed as they are 
originally input. FIG. 5 shows an example of the result of the recognition 
of the input character in FIG. 4. 
The operation of the apparatus having the above-described construction of 
the present invention will now be explained with reference to the 
flowchart in FIG. 3. 
Character recognition is usually performed when the apparatus is in the 
character input mode. When characters are written by depressing the input 
pen 11 in the input section 12, the information of the coordinates in the 
input section 12 are input to the processing block 2 in order that the 
information on the coordinates can be recognized as being a character. In 
step S41, the work area of the RAM 32b is initialized and a recognition 
result storage buffer in the recognition result storage means 23 is 
initialized. 
In step S42, it is determined that the inputting of character data has been 
terminated upon moving the input pen 11 into another input area 10 of 
input section 12. Recognition is performed on the basis of a conventional 
commonly used recognition method, such as a pattern matching method, when 
one character is written by depressing the input pen 11 in the input 
section 12, and a character code is determined based on the recognition 
result. 
In step S43, the calligraphic specimen of the input character is displayed 
on the liquid-crystal display section 13. An instruction to write a 
straight line formed by connecting the coordinate points of each stroke of 
a character input from the coordinate input section 31 is sent to the 
display control means 25. Thereafter, the display control means 25 sends 
out display dot coordinate data of the straight line and the 
liquid-crystal display section 13 displays the display dot coordinate 
data. As a result, the calligraphic specimen of the input character is 
displayed. The display coordinates are stored in a calligraphic specimen 
display storage buffer in a specific area of the RAM 32b. 
In step S44, the recognition result is stored in the recognition result 
storage means 23. Information, such as character codes or character 
positions obtained as a result of the recognition performed in step S42, 
is stored in a recognition result storage buffer in a specific area of the 
RAM 32b. 
In step S45, an operation for determining whether inputting of one sentence 
is terminated is performed by the sentence input processing continuation 
determination means 24. In this regard, it is generally determined that 
the inputting of one sentence is terminated when a period (.) is input. 
When the input character is recognized as a period in step S42, the CPU 32 
determines that the inputting of one sentence is terminated, and the 
process proceeds to step S46. When a character other than a period is 
recognized, it is determined that the inputting of one sentence is 
continuing, and the process proceeds to step S42, at which step the next 
character is input. 
In step S46, an operation for clearing the display of the calligraphic 
specimen of one sentence inputted thus far is performed. Data to clear the 
display is sent to the display control means 25. The data clears the 
display of the calligraphic specimen of one sentence displayed in step S43 
on the basis of the storage display coordinate data of the calligraphic 
specimen display storage buffer in a specific area of the RAM 32b, and the 
data is stored in step S43, causing the calligraphic specimen display on 
the liquid-crystal display section 13 to be cleared. 
In step S47, the result of the recognition of one sentence inputted thus 
far is displayed. The character code data of the recognition result 
storage buffer in a specific area of the RAM 32b, stored in step S44, is 
sent to the display control means 25, causing the recognition result to be 
displayed on the liquid-crystal display section 13. 
Thus, since the operations described above are performed in the 
above-described way, the display of the calligraphic specimens of 
characters, the input of which is in progress, as shown in FIG. 4, is 
changed to display the recognition result shown in FIG. 5. 
An operation for determining whether or not the inputting of one sentence 
is terminated on the basis of the input of a period has been explained 
above. There is a case in which it can be considered that the inputting of 
one sentence is terminated on the basis of a recognition other than that 
described above, and the recognition may be displayed. That is, the above 
case is one in which no inputting has occurred for five minutes or longer. 
In this case, an operation for measuring the time during which the 
inputting is discontinued may be performed so that, when no inputting has 
been performed for a given time, a determination is made as to whether or 
not the steps for clearing a display beginning with step S46 should be 
performed. 
In a case where the present invention is applied to a handwriting 
electronic pocket notebook, when an operation other than inputting of a 
character is performed (an input of something other than a character is 
made), it is desirable that an operation for determining whether the 
inputting be discontinued and steps starting with step S46 should be 
performed. Even though only an operation for recognizing characters one by 
one in step S42 has been explained, an operation for collectively 
recognizing characters may be performed since the recognition result can 
be displayed collectively in step S47. 
Many different embodiments of the present invention may be constructed 
without departing from the spirit and scope of the present invention. It 
should be understood that the present invention is not limited to the 
specific embodiments described in this specification. To the contrary, the 
present invention is intended to cover various modifications and 
equivalent arrangements included with the spirit and scope of the claims.