CN1195282C

CN1195282C - Character identification for obtained mark by camera

Info

Publication number: CN1195282C
Application number: CN 02119354
Authority: CN
Inventors: 镇立新; 黄建成
Original assignee: Motorola Inc
Current assignee: Motorola Mobility LLC; Google Technology Holdings LLC
Priority date: 2002-05-13
Filing date: 2002-05-13
Publication date: 2005-03-30
Anticipated expiration: 2022-05-13
Also published as: CN1458623A

Abstract

The present invention relates to a character identification method (20) for an obtained mark by a camera (17) connected with an electronic device (1). The character identification method (20) comprises the following steps that differences (27) of a stroke written on a surface are stored; the differences exist between a reference picture and a current picture; the reference picture and the current picture are respectively obtained by the camera (17) in step (22) and step (23); a determining step (28) determines whether the stroke forms a possible character or not; a combining step (29) combines the differences; a handwritten character is supplied; a character identification step (30) identifies the handwritten character subsequently.

Description

The character recognition of obtained mark by camera

Technical field

The present invention relates to obtain the character recognition of mark by camera.The present invention is specially adapted to the character recognition that (but might not be confined to) uses in portable phone, PDA(Personal Digital Assistant) or similar portable electric appts.

Background technology

In some cases, portable phone, PDA and other similar portable electric appts and ordinary electronic equipment allow the user by input pen and digitizing tablet (normally touch-screen) input characters symbol or alphanumeric information.These equipment can be made the hand-written character machine of being converted into representation (typewritten representation) usually.

The common methods that the hand-written character machine of being converted into is beaten representation partly comprises compares the key element of hand-written character with one group of predetermined template character.This step is finished by Character recognizer usually, and Character recognizer determines which group template character is the most similar to given hand-written character in the template character repertoire.This determines to be based upon usually on the basis of this possibility: selected template character can be identical with hand-written character.But digitizing tablet or touch-screen are relatively expensive, and the character that everyone writes distinguished also need a powerful processor.

In this instructions and claims, " comprise ", " comprising " or other similar word all represent containing of a kind of nonexcludability, therefore the method or the device that comprise a series of element are not to include only these elements, but also may comprise other unlisted element.

Summary of the invention

According to one aspect of the invention, a kind of method that the mark that is obtained by camera is carried out character recognition is provided, this camera links to each other with electronic equipment, said method comprising the steps of:

Between the continuous pictures that above-mentioned camera obtained, the difference of stroke (this stroke is write on a surface) is stored;

Determine whether above-mentioned stroke constitutes a possible character;

Provide a hand-written character in conjunction with above-mentioned difference;

Realization is to the character recognition of above-mentioned hand-written character.

Above-mentioned cohesive process is preferably in above-mentioned deterministic process and concludes that above-mentioned stroke carries out before constituting a possible character.As selection, above-mentioned cohesive process also can carry out after above-mentioned deterministic process be concluded possible character of above-mentioned stroke formation.

Obtain a current picture by obtaining a reference picture in thereafter, it is more desirable so to obtain continuous pictures.

Preferably difference is determined by relatively whether there are differences between reference picture and the current picture.

From reference picture, deduct current picture, so difference is determined more desirable.

Preferably after a preset time period expires, carry out determining step.

When the disparity range between the current stroke in the previous difference of stroke and the current picture greater than a threshold range value, it is more desirable to carry out determining step this moment.

Attempt hand-written character and template character are mated so that a character after the identification to be provided, the character recognition step with such feature is more desirable.

This method preferably also comprises the step that a signal further is provided, and this signal is based on that character of picking out from described Character mother plate as the character after the described identification.

This method preferably also comprises a subsequent step, demonstrates the machine identical with discerning the back character and beat form on display screen.

According to a further aspect of the invention, also provide a kind of electronic equipment, having comprised:

A processor;

A camera that links to each other with processor;

Wherein in use, described processor will be write the difference of stroke from the teeth outwards and store (this difference is present between the continuous pictures that above-mentioned camera obtains), determine whether above-mentioned stroke constitutes a possible character, provide a hand-written character in conjunction with above-mentioned difference, and realize character recognition above-mentioned hand-written character.

Described electronic equipment can suitably be realized any step above-mentioned.

Description of drawings

For making easy to understand of the present invention and enforcement, below with reference to accompanying drawing a preferred embodiment is described, wherein:

Fig. 1 is the block diagram of an embodiment of electronic equipment as described herein;

Fig. 2 is a flow chart, and the method that the mark that is obtained by the camera that links to each other with electronic equipment among Fig. 1 is carried out character recognition has been described;

Fig. 3 is the example of the stroke that obtains by the camera that links to each other with electronic equipment among Fig. 1.

Embodiment

In the accompanying drawings, the same numbers in the different accompanying drawings is represented components identical.Referring to Fig. 1, electronic equipment 1 comprises radio frequency communication unit 2, and unit 2 is connected with processor 3 and communicates.The input interface that is expressed as display screen 5 and keyboard 6 forms also is connected with processor 3 and communicates.In addition, also having camera 17 to be connected with processor 3 communicates.

Processor 3 comprises encoder/decoder 11, and it links to each other with ROM (read-only memory) (ROM) 12, and ROM (read-only memory) 12 is used for sound and may carries out data storage by the Code And Decode of electronic equipment 1 transmission or other signal that receives.Processor 3 also comprises microprocessor 13, and microprocessor 13 and encoder/decoder 11 link to each other with relevant character ROM (read-only memory) (ROM) 14.Microprocessor 13 also links to each other with random-access memory (ram) 4, keyboard 6, display screen 5, camera 17 and static programmable memory 16.

The auxiliary output of microprocessor 13 is connected to alarm module 15, and typical alarm module 15 comprises loudspeaker, vibrator motor and relevant driver.Character ROM (read-only memory) 14 storage codes are used for communication unit 2 is received and encoded or decoded by the Word message of keyboard 6 input.In the present embodiment, character ROM (read-only memory) 14 also is microprocessor 13 and the Character mother plate group storage operation sign indicating number (OC) that is used for character recognition.Operational code (OC) is used for running application on electronic equipment 1.

Radio frequency communication unit 2 is a combined receiver and transmitter, has a common antenna 7.Communication unit 2 has a radio transceiver 8, and it is connected to antenna 7 by radio-frequency amplifier 9.Radio transceiver 8 also links to each other with a combined modulator/demodulator 10, and modulator/demodulator 10 is connected to processor 3 with communication unit 2.

Electronic equipment 1 can be any electronic installation, comprises portable phone, plain old telephone, laptop computer or PDA.Camera 17 can carry out the Image Acquisition of mark, and processor 3 can detect the mark that obtains and carry out character recognition subsequently through programming.

Referring to Fig. 2, this figure has illustrated method 20, is used for the mark that is obtained by the camera 17 that links to each other with electronic equipment 1 is carried out character recognition.In beginning step 21, the camera lens that the user makes camera 17 usually is towards a piece of paper and trigger a button on the keyboard 6 subsequently.Finish the step 22 of obtaining reference picture, this can cause camera to obtain the image of described paper usually.Should be understood that it may not is blank on this paper, above may be underlined or print or write mark, therefore described image may be blank or opposite.Finish the step 23 of obtaining current picture by camera.Whether checking procedure 24 there are differences by the image of recently determining the reference picture acquisition is compared with current picture.Determine that by from reference picture, deducting current picture this species diversity, the result of any non-zero all are difference, realize this contrast like this.In checking procedure 35, if there is no difference and do not exceed time threshold (perhaps not expiring), then assignment step 25 just is appointed as new reference picture with

current picture.Step

23,24,35 and 25 is carried out repeatedly, when contrast, there are differences between the new current picture of determining in new image that reference picture obtained and step 23, to obtain until checking procedure 24, perhaps the button that starts on the keyboard 6 of user has been cancelled method 20, perhaps preset time period expires and be detected in step 35.

When step 24 defines difference, processor 3 completing steps 26, the difference between selection image that reference picture obtained and current picture when contrast.This species diversity generally can be the line (stroke) that constitutes a character part on the paper surface.Processor 3 is finished the step 26 of this difference of storage subsequently, is stored among the RAM 4 in difference described in this step.Possible character is searched check program 28 and is carried out verification subsequently, so that determined whether to find a possible character, the previous image difference of the stroke of storage carries out verification among current stroke in this step in 3 pairs of current pictures of processor and the RAM 4.Return referring again to step 35,, then also will carry out step 28 if the time cycle has surpassed time threshold (be the preset time period expires, this predetermined period of time was generally 2 seconds).If at the stroke differences of step 28 check greater than a thresholding gap value, then think on described paper, write one may character.Apparent to those skilled in the art, this thresholding gap value is apart from determining by the relative mistake between the contrast stroke.

If do not find the possibility character in step 28, then

step

25 and 23 is carried out repeatedly, detect until the preset time period expires and in step 35, perhaps when contrast, there are differences between the image of the definite reference picture acquisition of step 24 and current picture, carry out

step

26,27 and 28 thereafter repeatedly.In case step 28 has determined to find a possible character, the step 29 in conjunction with store discrepancy just combines all differences that the step 27 of store discrepancy is stored, and generates a hand-written character.

30 pairs of hand-written characters of character recognition step carry out character recognition subsequently.Can use any in the art known method to finish character recognition, for example U.S. Pat 6226403 described methods (at this by reference and in conjunction with this method).In view of the above, character recognition step 30 is intended to the Character mother plate collection of storage in hand-written character and the character ROM (read-only memory) 14 is mated.

If character recognition step 30 fails to find the coupling character, then one not the matching characteristic position with set.Otherwise will think that character recognition is successful, not matching characteristic position reset.Stop checking procedure 31 subsequently and determine whether method 20 should end at termination step 34, if beginning step 21 and the time period that stops between the checking procedure 31 have surpassed a default maximum input string time cycle (being generally 1 minute), perhaps the user then enters and stops step 34 from termination order of keyboard 6 inputs.If identify hand-written character, then identify character and coherent signal by processor processing, the character that this signal relied on is selected from above-mentioned Character mother plate and is used as the above-mentioned character that identifies.This signal can be used for carrying out or starting the function of electronic equipment 1.As selecting or appendage, identify template form (the identical with it machine that promptly preestablishes font is beaten form) meeting demonstration on display screen 5 usually of character, for user's inquiry.Determine that methods 20 should proceed if stop checking procedure 31, the then successful test for identification step 32 pair not state of matching characteristic position is tested.If not matching characteristic position set, then hand-written character is unrecognized in character recognition step 30 goes out, and suppose that potential character is incomplete, method 20 is returned step 25, attempts to obtain more picture and store more difference to be increased on the incomplete character of supposition.As selection, if not matching characteristic position reset, the difference that the difference that then resets storing step 33 will be stored among the RAM 4 is removed, and the timer that preestablishes the time cycle is resetted, thereby allows another character is tested.Method 20 is returned step 25 and is attempted new hand-written character is obtained and discerns.

Referring to Fig. 3, this figure is an example of the stroke that obtained by camera, in order to further specify the present invention.In step 22, obtain the paper 40 that has context marker as with reference to picture 41.In step 23, the paper 40 that has stroke 43 becomes current picture 42, and in step 27 storage its difference (being stroke 43).Become a new reference picture 42 at the current picture 42 of step 25 subsequently, and obtain the new current picture 45 that has stroke 43,46 in step 23.Step 27 store discrepancy (being stroke 46).Current subsequently picture 45 becomes a new reference picture 45 in step 25, and obtains the new current picture 48 that has stroke 43,46 and 49 in step 23.In step 27 storage its difference (being stroke 49).Current subsequently picture 48 becomes a new reference picture 48 in step 25, and obtains the new current picture 54 that has

stroke

43,46,49 and 52 in step 23.Its difference (being stroke 52) is stored in step 27.

Checking procedure 28 is determined gap between strokes 52 and other stroke 43,46,49 greater than the thresholding gap value, and finds out a possible character thus.Thereby step 29 combines the stored gap of stroke 43,46 and 49, produces a potential character " A ", identifies with numeral 53.Carry out character recognition at step 30 pair potential character " A " subsequently, and if character recognition success, the then stored difference of stroke 43,46,49 promptly in step 33, be reset (deletion from ROM 14).So current picture 54 becomes a new reference picture 54 in step 25, and obtain the new current picture 56 that has

stroke

43,46,49,54 and 57 in step 23.Its difference (being stroke 57) is stored in step 27.If do not detect other stroke (difference), detect step 35 and determine that promptly the preset time cycle expires, checking procedure 28 thinks and has found a possible character that step 29 combines the

difference

54,57 of storage, produce a potential character " B ", identify with numeral 58.Carry out character recognition subsequently, method stops in step 34.

The invention provides a kind of effective ways of importing handwritten text character and alphanumeric information expediently, do not need to use digitizing tablet or touch-screen.Method 20 is to store by the difference of stroke between the continuous pictures that camera 17 obtains that will write in step 27 at paper surface in essence, thereby carries out being obtained by camera the character recognition of mark.Detect step 28 and be used for determining whether stroke constitutes a possible character.Near in the step 29, the difference before the step 28 is combined, determine whether stroke constitutes a possible character, thereby this hand-written character is provided.As selection mode, as shown in Figure 2, after step 28, step 29 realizes the difference combination, determines whether stroke constitutes a possible character.Subsequently, carry out character recognition by step 30 pair hand-written character.

Though only describe a preferred one exemplary embodiment of the present invention in detail, its meaning be not limit the scope of the invention, applicability and configuration.On the contrary, the detailed description to this preferred one exemplary embodiment can make those skilled in the art be implemented preferred one exemplary embodiment of the present invention.Will be understood that not departing under the definite spirit and scope of the invention situation of appended claims, can carry out various modifications the function and the configuration of each assembly.

Claims

1. method of carrying out character recognition for the mark that camera obtained that links to each other with electronic equipment, this method may further comprise the steps:

The difference of writing at a lip-deep stroke is stored, this difference is present between the continuous pictures that camera obtains, obtain described continuous pictures by obtaining a reference picture and obtaining a current picture subsequently, by whether there are differences to determine described difference between more described reference picture and the current picture;

Determine whether described stroke constitutes a possible character;

Described difference is combined, thereby hand-written character is provided;

Described hand-written character is carried out character recognition.

2. method according to claim 1 is wherein determined described difference by deduct described current picture from described reference picture.

3. method according to claim 1 wherein begins to carry out described certain step when the preset time period expires, described predetermined period of time is the maximum time of obtaining the picture differences.

4. method according to claim 1 wherein when the disparity range between the current stroke is greater than a threshold range value in the previous difference of stroke and the described current picture, is carried out described determining step.

5. method according to claim 1, the feature of wherein carrying out described character recognition step are to attempt described hand-written character and template character are mated, thereby the character after the identification is provided.

6. method according to claim 1 wherein, after the step of carrying out character recognition, also has the step that a signal is provided, and this signal is based on that character of picking out from described Character mother plate as the character after the described identification.

7. method according to claim 6, wherein, after the step that a signal is provided, described method comprises a subsequent step, demonstrates the machine identical with described identification back character and beat form on display screen.