WO2018130216A1

WO2018130216A1 - Method and device for recognizing characters on license plate

Info

Publication number: WO2018130216A1
Application number: PCT/CN2018/072593
Authority: WO
Inventors: 丁超员; 何海峰; 钮毅; 罗兵华; 林翠翠; 蔡晓蕙; 钱华; 韦立庆
Original assignee: 杭州海康威视数字技术股份有限公司
Priority date: 2017-01-16
Filing date: 2018-01-15
Publication date: 2018-07-19
Also published as: CN108319951A; CN108319951B

Abstract

A method and a device for recognizing characters on a license plate. The method comprises: acquiring a license plate area image of a license plate to be recognized (101); determining a continuous character sequence having most characters in the license plate area image as initial primary segment characters of said license plate (102); determining, according to preset sub-segment character characteristics, whether the characters located at the left end or right end of the initial primary segment characters comprise characters belonging to sub-segment characters (103); deleting the characters which are located at the left end or right end of the initial primary segment characters and belong to the sub-segment characters, to obtain primary segment characters of said license plate (104); and determining the sub-segment characters of said license plate according to the location of the primary segment characters on the license plate area image (105). Said method is able to recognize primary segment characters and sub-segment characters of a plurality of types of license plates.

Description

Method and device for identifying characters in license plate

This application claims the priority of the Chinese Patent Application entitled "A Method and Apparatus for Recognizing Characters in License Plates" filed on January 16, 2017 by the Chinese Patent Office, Application No. 201710028236.X, the entire contents of which are incorporated by reference. In this application.

Technical field

The present application relates to the field of intelligent transportation, and in particular to a method and apparatus for recognizing characters in a license plate.

Background technique

With the rapid increase in the number of vehicles, the intelligent identification technology of license plates has been widely used in parking lots, urban roads and highways to automatically capture and identify vehicle grades.

Currently, the method for identifying characters in a license plate is:

The first step: obtaining the license plate area corresponding to the license plate to be identified through the camera device;

The second step: identifying characters in the license plate area;

Step 3: split the characters in the license plate area according to the preset template;

The fourth step: comparing the characters in the divided license plate area with the individual character templates in the preset template to determine the characters in the license plate area.

Usually, the license plate is divided into a single-layer license plate and a double-layer license plate. The characters in the single-layer license plate include not only a series of consecutive character sequences, but also other characters that differ in position or format from the character sequence. For convenience of description, the character sequence is generally referred to as a main segment character, and the other characters are referred to as sub-segment characters. In addition, the types of license plates vary from country to country, and there is no uniform standard. In particular, the Gulf Cooperation Council (GCC) national member of the UAE emirates has not only a wide range of license plates, but also various types of license plates. The character styles are also different. Since the above-mentioned method for recognizing characters in the license plate has a limited variety of templates, for the application scene with a wide variety of license plates, the method of recognizing the characters in the license plate cannot accurately identify the main segment characters and the sub-segment characters from the plurality of types of license plates. .

Summary of the invention

The purpose of the embodiments of the present application is to provide a method and apparatus for recognizing characters in a license plate, which can identify main segment characters and sub-segment characters in a plurality of license plate types. The specific technical solutions are as follows:

An embodiment of the present application provides a method for recognizing a character in a license plate, the method comprising: acquiring a license plate area image of a license plate to be identified; determining a sequence of consecutive characters having the largest number of characters in the license plate area image as Determining an initial main segment character in the license plate; determining, according to the preset sub-segment character feature, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character; The character belonging to the left segment or the right end of the segment character is deleted, and the main segment character in the license plate to be identified is obtained; and the position of the main segment character in the license plate region image is determined according to the position of the main segment character in the license plate image. Subsection character.

Optionally, the step of determining, according to the preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main-segment character, includes: starting from the initial main segment character Extracting, by the left end, a first preset number of characters or extracting a second preset number of characters from the right end; determining whether the characters in the first preset number of characters or the second preset number of characters are the same; Determining, by the first preset number of characters or the second preset number of characters, a size of the first smaller number of the first preset number of characters, or the first a size of a second smaller one of the plurality of preset characters; determining whether the first smaller character or the second smaller character is a letter; if the first smaller character or the second smaller If the character is a letter, it is determined that the first smaller character or the second smaller character belongs to the sub-segment character; if the first preset number of characters or the second preset number of characters The characters are the same size, or the first Small characters and the second character is not a small letter, it is determined that the character belongs to the character sub-segments not present in the initial main character at the character segment of the left or right.

Optionally, the step of determining, according to the location of the main segment character in the license plate area image, the sub-segment character in the license plate to be identified, comprising: according to the main segment character in the license plate area a location in the image, determining a connected domain in which the sub-segment character is located in the license plate area image; determining, in the connected domain, a sub-segment area in which the sub-segment character is located; according to a preset classification model, Determining the sub-segment characters in the license plate to be identified in the sub-segment area.

Optionally, the step of determining, according to a location of the main segment character in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image, including: according to the main segment character Determining, at a position in the license plate area image, a connected domain in which the sub-segment character is located to the left of the main segment character; or determining according to a location of the main segment character in the license plate area image The connected domain where the sub-segment character is located is located to the right of the main segment character.

Optionally, the step of determining that the connected domain where the sub-segment character is located is located on the left side of the main segment character according to the location of the main segment character in the license plate area image includes: determining the first Whether the height of the area is consistent with the height of the main segment character; when the height of the first area is consistent with the height of the main segment character, determining that the first area is a connected domain in which the sub-segment character is located; The first area is an area from a left side of the main segment character to a third number of characters from the left side; or determining a height of the second area and the main segment character Whether the height is consistent; when the height of the second area is consistent with the height of the main segment character, determining that the second area is a connected domain in which the sub-segment character is located; wherein the second area is a slave The left side of the main segment character is a region between a preset fourth number of characters and a predetermined fifth number of characters from the left side; when the height of the second region is different from the main segment character Highly inconsistent and the first judgment The height of the main section and the height of the character region when the two are the same, inverting the colors in the second region, determining whether to execute the second region and the height of the main section of the same character.

Optionally, the step of determining, according to the location of the main segment character in the license plate area image, that the connected domain where the sub-segment character is located is located on a right side of the main segment character, including: determining a third Whether the lower bound of the region is consistent with the character of the main segment, and the height of the third region is three-quarters of the height of the main segment character; if yes, determining that the third region is the sub-segment character a connected domain; wherein the fourth area is an area between a sixth number of characters from a right side of the main character character and a seventh number of characters preset to the right side; Or determining whether the height of the fourth area is consistent with the height of the main segment character; if yes, determining that the fourth area is a connected domain where the sub-segment character is located; wherein the fourth area is a slave Determining, on the right side of the main segment character, an area between the preset eighth number of characters and a preset ninth number of characters from the right side; or determining the height of the fifth area and the height of the main segment character Whether it is consistent; if yes, then determine The fifth area is a connected domain in which the sub-segment character is located; wherein the fifth area is a preset tenth number of characters from a right side of the main segment character to a preset distance from the right side An area between eleven numbers of characters.

Optionally, the step of determining, according to the preset classification model, the sub-segment characters in the to-be-identified license plate in the sub-segment area, including: determining, according to a preset first classification model, Whether the sub-segment character exists in the sub-segment area; if yes, determining the sub-segment character in the to-be-identified license plate in the sub-segment area according to a preset second classification model; And executing, according to the location of the main segment character in the license plate area image, determining a connected domain in which the sub-segment character is located in the license plate area image.

An embodiment of the present application further provides an apparatus for recognizing a character in a license plate, the apparatus comprising: an acquiring unit, configured to acquire an image of a license plate area of a license plate to be identified; and a first determining unit, configured to use the license plate area a sequence of consecutive characters having the largest number of characters in the image, determined as the initial main segment character in the license plate to be identified; and a determining unit configured to determine, according to the preset sub-segment character feature, the left end or the right end of the initial main segment character Whether the character belonging to the sub-segment character exists in the character; the deleting unit is configured to delete the character belonging to the sub-segment character located at the left end or the right end of the initial main segment character to obtain the main segment character in the to-be-identified license plate; And a second determining unit, configured to determine a sub-segment character in the license plate to be identified according to a location of the main segment character in the license plate area image.

Optionally, the determining unit includes: an extracting subunit, a determining subunit, a first determining subunit, and a second determining subunit; and the extracting subunit is configured to extract from the left end of the initial main segment character a predetermined number of characters or a second preset number of characters from the right end; the determining subunit, configured to determine a character size of the first preset number of characters or the second preset number of characters Whether the first determining subunit is configured to determine the first preset number if the character sizes in the first preset number of characters or the second preset number of characters are not the same a size of a first smaller character in the character, or a size of a second smaller one of the second predetermined number of characters; determining whether the first smaller character or the second smaller character is a letter; Determining that the first smaller character or the second smaller character belongs to the sub-segment character; the second determining sub-unit, For the first preset number of characters or places The character size of the second preset number of characters is the same, or the first smaller character and the second smaller character are not letters, and then the character is located at the left end or the right end of the initial main segment character. There are no characters belonging to the sub-segment characters.

Optionally, the second determining unit includes: a third determining subunit, a fourth determining subunit, and a fifth determining subunit; and the third determining subunit, configured to be according to the main segment character Determining, in a location in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image; the fourth determining sub-unit, configured to determine, in the connected domain, a sub-segment character a segment determining unit, configured to determine the sub-segment character in the to-be-identified license plate in the sub-segment region according to a preset classification model.

Optionally, the third determining subunit includes: a sixth determining subunit and a seventh determining subunit; and the sixth determining subunit, configured to be located in the license plate area image according to the main segment character a location, determining that the connected domain where the sub-segment character is located is located to the left of the main segment character; or the seventh determining sub-unit for determining a location of the main segment character in the license plate area image And determining that the connected domain where the sub-segment character is located is located to the right of the main segment character.

Optionally, the sixth determining subunit includes: an eighth determining subunit, a ninth determining subunit, and an executing subunit; and the eighth determining subunit, configured to determine a height of the first area and the main Whether the height of the segment character is consistent; when the height of the first region is consistent with the height of the main segment character, determining that the first region is a connected domain in which the sub-segment character is located; wherein the first region An area between the left side of the main segment character and a third number of characters from the left side; or the ninth determining subunit, configured to determine the height of the second area and the main Whether the height of the segment character is consistent; when the height of the second region is consistent with the height of the main segment character, determining that the second region is a connected domain in which the sub-segment character is located; wherein the second region An area between a fourth number of characters from a left side of the main segment character and a fifth number of characters preset from the left side; the execution subunit, when the The height of the two regions and the height of the main segment character Consistently, and when it is determined for the first time whether the height of the second region is consistent with the height of the main segment character, the color in the second region is reversed, and the determining the height of the second region and the main segment are performed Whether the height of the characters is the same.

Optionally, the seventh determining subunit includes: a tenth determining subunit, an eleventh determining subunit, and a twelfth determining subunit; and the tenth determining subunit, configured to determine a lower bound of the third region Whether it is consistent with the main segment character, and the height of the third region is three-quarters of the height of the main segment character; if yes, determining that the third region is the communication where the sub-segment character is located a region; wherein the fourth region is an area between a sixth number of characters from a right side of the main segment character and a seventh number of characters from the right side; or An eleven determining subunit, configured to determine whether a height of the fourth area is consistent with a height of the main segment character; if yes, determining that the fourth area is a connected domain where the sub-segment character is located; The fourth area is an area between an eighth number of characters from a right side of the main character character and a ninth number of characters preset to the right side distance; or the twelfth determiner a unit for determining a height of the fifth area and the main section Whether the height of the characters is consistent; if yes, determining that the fifth area is a connected domain where the sub-segment character is located; wherein the fifth area is a preset distance from a right side of the main segment character Tens of characters to an area between the eleventh number of characters preset to the right side.

Optionally, the fifth determining subunit includes: a thirteenth determining subunit, a fourteenth determining subunit, and a fifteenth determining subunit; the thirteenth determining subunit, configured to be according to a preset a first classification model, determining whether the sub-segment character exists in the sub-segment area; the fourteenth determining sub-unit, configured to: if the sub-segment character exists in the sub-segment area, according to a preset a second classification model, the sub-segment character in the license plate to be identified is determined in the sub-segment area; the fifteenth determining sub-unit is configured to: if the sub-segment does not exist in the sub-segment area And performing, according to the position of the main segment character in the license plate area image, determining a connected domain in which the sub-segment character is located in the license plate area image.

An embodiment of the present application further provides a storage medium for storing executable code for performing a method of identifying characters in a license plate as described above at runtime.

An embodiment of the present application further proposes an application for performing a method of recognizing characters in a license plate as described above at runtime.

An embodiment of the present application further provides an apparatus for recognizing characters in a license plate, including: a processor and a memory;

The memory is for storing executable program code;

The processor, configured to execute a program corresponding to the executable program code by reading executable program code stored in the memory to perform a method of recognizing a character in a license plate as described in any of the above.

The method and device for recognizing a character in a license plate provided by the embodiment of the present application, firstly, determining the initial main segment character in the license plate to be identified in the obtained license plate area image of the license plate to be identified; and then determining the initial main segment character Whether the character belonging to the sub-segment character exists in the left or right end character; the character belonging to the sub-segment character at the left end or the right end of the initial main segment character is deleted, and the main segment character of the license plate to be recognized is obtained; finally, according to the main segment character The position of the sub-segment in the license plate to be identified. In this way, the interference of the sub-segment characters that are tightly connected with the main segment character can be excluded, the accurate main segment character is obtained, and the sub-segment characters are determined according to the precise main segment character. Since the embodiment of the present application does not use a fixed template, multiple types of single-layer license plates can be identified according to different application scenarios, and the scope of application is wide.

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings to be used in the embodiments or the related art description will be briefly described below. Obviously, the drawings in the following description are only Some embodiments of the application may also be used to obtain other figures from those of ordinary skill in the art without departing from the scope of the invention.

1 is a flow chart of a method for recognizing characters in a license plate according to an embodiment of the present application;

2 is a schematic view of a plurality of license plates according to an embodiment of the present application;

FIG. 3 is still another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application; FIG.

4 is another flow chart of a method for recognizing characters in a license plate according to an embodiment of the present application;

FIG. 5 is still another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application; FIG.

FIG. 6 is still another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application; FIG.

7 is a structural diagram of an apparatus for recognizing characters in a license plate according to an embodiment of the present application;

FIG. 8 is still another structural diagram of an apparatus for recognizing characters in a license plate according to an embodiment of the present application; FIG.

FIG. 9 is a schematic diagram of an apparatus for recognizing characters in a license plate according to an embodiment of the present application.

detailed description

The technical solutions in the embodiments of the present application are clearly and completely described in the following with reference to the drawings in the embodiments of the present application. It is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

The embodiment of the present application discloses a method for recognizing characters in a license plate. Referring to FIG. 1, FIG. 1 is a flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application, including the following steps:

Step 101: Acquire an image of a license plate area of the license plate to be identified;

Step 102: Determine a sequence of consecutive characters having the largest number of characters in the license plate area image as an initial main segment character in the to-be-identified license plate;

The embodiment of the present application is applied to identify a main segment character and a sub-segment character in a single-layer license plate.

First, the scene image including the license plate to be identified may be acquired by the image capturing device, and the license plate area image corresponding to the license plate to be identified is determined in the scene image;

Then, all the characters in the license plate area image are identified, and all the recognized characters are used as the rough recognition main segment characters in the license plate to be recognized, but the characters located in the opposite region of the main background color of the license plate to be recognized are not included.

It can be understood that when the sub-segment character is included in the license plate to be identified, the sub-segment character may be included in the rough recognition main segment character.

For example, as shown in FIG. 2, FIG. 2 is a schematic diagram of various license plates according to an embodiment of the present application. In FIG. 2, the rough identification main segment character corresponding to the license plate A1 may be 96078, and the rough identification main segment character corresponding to the license plate A2. May be 54848, the rough identification main segment character corresponding to the license plate A3 may be 8308, the rough recognition main segment character corresponding to the license plate A4 may be 54977, the rough identification main segment character corresponding to the license plate A5 may be 62709, the rough identification main corresponding to the license plate A6 The segment character may be 58562, the rough recognition main segment character corresponding to the license plate A7 may be58626, the rough recognition main segment character corresponding to the license plate A8 may be 45920, and the rough recognition main segment character corresponding to the license plate A9 may be 32415, and the license plate A10 corresponds to the coarse The identification of the main segment character may be 98952, the rough recognition main segment character corresponding to the license plate A11 may be 40163, the rough recognition main segment character corresponding to the license plate A12 may be 9186, and the rough recognition main segment character corresponding to the license plate B1 may be 26029, the license plate B2 corresponding The rough recognition main segment character may be 3327, the rough identification main segment character corresponding to the license plate B3 may be 7778D, and the rough recognition main segment character corresponding to the license plate C1 may be G4297, and the license plate C2 corresponds to the coarse The main character of the main segment may be 8544. The rough recognition main segment character corresponding to the license plate D1 may be 3890GAA, the rough recognition main segment character corresponding to the license plate D2 may be 1021, and the rough recognition main segment character corresponding to the license plate D3 may be 0528; visible, the license plate The corresponding rough recognition main segment character may not be an accurate main segment character, and may include sub-segment characters; for example, the rough recognition main segment character G4297 corresponding to the license plate C1 includes the sub-segment character G, and the coarse identification main segment character corresponding to D1 The sub-segment character GAA is included in the 3890GAA.

Next, in the coarse identification character, the continuous character sequence with the largest number of characters is determined as the initial main segment character; thus, the sub-segment characters far from the main segment character can be excluded from the coarse recognition main segment character, and further limited The range of the main segment characters. Specifically, the initial main segment character may be determined according to the pitch, width, and center distance information of the character in the rough identification main segment character. However, in a scene where the sub-segment characters are closer to the left or right side of the main segment character, the sub-segment characters may still be included in the left or right side of the initial main segment character.

Therefore, in order to obtain an accurate main segment character and to determine the sub-segment character based on the exact main segment character, the initial main segment character needs to be further defined.

For example, for the license plate C1 and the license plate D1 in FIG. 2, it is necessary to further define the initial main segment characters corresponding to the license plate C1 and the license plate D1.

Step 103: Determine, according to a preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character;

In this step, it is possible to determine whether there is a character belonging to the sub-segment character in the character at the left end of the initial main segment character, and whether there is a character belonging to the sub-segment character in the character at the right end of the initial main segment character. For ease of understanding, the embodiment of the present application is described in the order of first determining the left end and then determining the right end. Of course, the step of determining the left end may also be performed simultaneously with the step of determining the right end. It should be noted that, in the present application, whether there is a character belonging to the sub-segment character in the character located at the left end of the initial main segment character, and whether the character belonging to the sub-segment character exists in the character located at the right end of the initial main segment character The order of execution of the steps is not limited.

In a preferred embodiment of the present application, referring to FIG. 3, FIG. 3 is still another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application. Step 103 may specifically include:

Sub-step 11, extracting a first preset number of characters from the left end of the initial main segment character or extracting a second preset number of characters from the right end;

Sub-step 12, determining whether the character sizes in the first preset number of characters or the second preset number of characters are the same;

Sub-step 13, determining, if the character size of the first preset number of characters or the second preset number of characters is different, determining a size of the first smaller one of the first preset number of characters Or the size of the second smaller number of the second predetermined number of characters; determining whether the first smaller character or the second smaller character is a letter; if the first smaller character or Determining that the second smaller character is a letter, and determining that the first smaller character or the second smaller character belongs to the sub-segment character;

Sub-step 14, if the characters of the first preset number of characters or the second preset number of characters are the same, or the first smaller character and the second smaller character are not letters Then, it is determined that there is no character belonging to the sub-segment character in the character at the left end or the right end of the initial main segment character.

In practical applications, the distance between some sub-segment characters and the main segment characters is relatively close, and in normal cases, the size of the sub-segment characters that are closer to the main segment characters is smaller than the size of the main segment characters, and the main segment characters are The closer sub-segment characters are letters; therefore, the initial main segment can be determined by determining the size of the character located to the left or right of the initial main segment character and determining whether the character at the left or right end of the initial main segment character is a letter. Whether the character at the left or right end of the character belongs to the sub-segment character.

The embodiment of the present application can be applied to determine a character in any license plate. For example, it can be used to determine a character in a license plate of a member of the GCC country in the UAE, or a character in another type of license plate, which is not limited in the embodiment of the present application. Moreover, in the character determining process, the first preset number of characters may be two characters from left to right in the initial main segment character, and the second preset number of characters may be from left to right in the initial main segment character. The fourth and fifth characters; of course, the first preset number value and the second preset number value can be changed according to actual needs.

Specifically, when determining whether the left side of the initial main segment character is connected to the sub-segment character, first, the first character and the second character may be extracted in the order from left to right at the left end of the initial main segment character; And determining whether the size of the first character and the second character are the same; if the size of the first character and the second character are different, the first character is usually less than the first character. The other characters, including the second character, determine whether the first character is a letter after re-determining the size of the first character; if the first character is a letter, the first character It belongs to a sub-segment character; if the first character and the second character have the same size, or the first character is not a letter, the left end of the initial main segment character does not have a character belonging to the sub-segment character.

It should be noted that, in the initial main segment character, the first character is different in size from other characters, which may result in inaccurate recognition of the first character in the initial main segment character; therefore, After determining the size of the first character, the first character needs to be re-identified to determine whether the first character is a letter.

When judging whether the right side of the initial main segment character is connected with the sub-segment character, first, at the right end of the initial main segment character, the fourth character and the fourth character after the left-to-right order may be extracted; And determining whether the size of the characters after the fourth character and the fourth character are the same; if the characters of the fourth character and the fourth character are different in size, the fifth character is usually If the character after the fifth character is smaller than other characters including the fourth character, the characters after the fourth character are re-determined, that is, after the fifth character and the fifth character. After the size of the character, determining whether the fifth character and the character after the fifth character are letters; if the fifth character and the character after the fifth character are letters, The fifth character and the character after the fifth character belong to the sub-segment character; if the fourth character and the character after the fourth character are the same size, or the fifth character and the fifth Characters after the characters are not letters, and there are no characters belonging to the sub-segment characters at the right end of the initial main segment character.

It should be noted that, in the initial main character, the characters after the fourth character and the fourth character are different from the other characters, which may result in the initial main segment character being The recognition of the fifth character and the characters after the fifth character is inaccurate; therefore, after determining the size of the fifth character and the character after the fifth character, the fifth The character and the character after the fifth character are re-identified to determine whether the fifth character and the character after the fifth character are letters.

For example, the license plate C1 and the license plate D1 in FIG. 2; wherein the initial main segment character corresponding to the license plate C1 is G4297, and the first character and the second character corresponding to the order from left to right are G and 4, respectively. It can be seen that the size of the character G is smaller than the character 4, and there is a blank area in the upper part of the character 4, which may cause misidentification of the character G in the initial main segment character; therefore, it is necessary to re-recognize the character G after re-determining the size of the character G, when When it is determined that the character G is a letter, it can be determined that the left side of the initial main segment character corresponding to the license plate C1 is connected with the sub-segment character, and the first character G is a sub-segment character; and the initial main segment character corresponding to the license plate D1 is 3890GAA, According to the fourth character and the fourth character after the order from left to right, the characters are 0 and GAA respectively. It can be seen that the size of the character GAA is smaller than the character 0, and the character GAA is an English letter, and the upper and lower parts of the character GAA are There is a blank area, which may cause misidentification of the character GAA in the initial main segment character; therefore, it is necessary to re-recognize the character GAA after re-determining the size of the character GAA, when determining that the character GAA is a letter The initial character may determine the license plate main section E corresponding right sub-segment is connected to the character, and the fifth character after character GAA characters and fifth sub-segment characters.

It should be noted that, because there are many types of license plates in various countries and regions around the world, and the difference in character styles in license plates is also large, in order to more accurately identify the characters in the license plate, according to the current application area, the license plate middle sub-segment characters A scene in which the characters of the main segment are closer to each other, and a judgment rule that distinguishes the main segment character from the sub segment character close to the main segment character is summarized.

Specifically, according to the style of the characters in the license plate in the current application area, all the license plates whose sub-segment characters are located on the left or right side of the main segment character and are close to the main segment character may be selected, and the sub-segment characters in the license plate characters are summarized. The feature, and according to the characteristics of the sub-segment characters in the license plates, a judgment rule capable of distinguishing the sub-segment characters of the license plates is used to determine whether the left or right side of the rough-recognition main segment character is connected with the sub-segment characters.

It should be noted that, with the increase of the license plate type of the Emirates emirates of the GCC countries, the embodiment of the present application can expand on the basis of the original judgment rules according to the distribution of characters in the newly added license plate to identify the new license plate type. .

Of course, the application scenario of the embodiment of the present application is not limited to the members of the GCC countries in the UAE emirates. In practical applications, it can also be applied to identify license plate types of other countries and regions. Specifically, according to the license plates of other countries and regions. The distribution of characters determines the judgment rule for judging whether the left or right side of the main character of the rough recognition is connected to the sub-segment character. For example, for license plates of members of the GCC countries in the UAE emirates, character recognition rules can be determined based on their character distribution.

Step 104: Delete a character belonging to a sub-segment character located at a left end or a right end of the initial main segment character to obtain a main segment character in the to-be-identified license plate;

In this step, when it is determined that the character located at the left end or the right end of the initial main segment character belongs to the sub-segment character, the character belonging to the sub-segment character may be deleted from the left end or the right end of the initial sub-segment character to obtain an accurate main segment character.

For example, as shown in FIG. 2, the license plate C1 and the license plate D1, the initial main segment character corresponding to the license plate C1 is G4297, and the character G belongs to the sub-segment character, and the character G can be deleted from the initial main segment character to obtain an accurate main segment character. 4297; the initial main segment character corresponding to the license plate D1 is 3890GAA, and the character GAA belongs to the sub-segment character, and the character GAA can be deleted from the initial main segment character 3890GAA, and the exact main segment character is 3890.

Step 105: Determine a sub-segment character in the license plate to be identified according to a location of the main segment character in the license plate area image.

Specifically, through the processing of steps 101-104, the accurate main segment character has been obtained, and then, the sub-segment character can be determined according to the accurate main segment character.

In another preferred embodiment of the present application, referring to FIG. 4, FIG. 4 is another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application. The step 104 may include:

Sub-step 21, determining, according to a location of the main segment character in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image;

Sub-step 22, determining, in the connected domain, a sub-segment area in which the sub-segment character is located;

Sub-step 23, determining the sub-segment characters in the to-be-identified license plate in the sub-segment area according to a preset classification model.

Specifically, the connected domain in which the sub-segment character is located may be determined according to the position of the exact main segment character in the license plate area image; next, the minimum circumscribed rectangle including the sub-segment region is determined in the connected domain, and the minimum external connection may be considered The rectangle is the sub-segment area; finally, the sub-segment characters are identified in the sub-segment area according to the preset classification model.

Further, in a preferred embodiment of the present application, referring to FIG. 5, FIG. 5 is still another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application. The sub-step 21 may specifically include:

Sub-step 31, determining, according to the location of the main segment character in the license plate area image, that the connected domain where the sub-segment character is located is located on the left side of the main segment character; or

Sub-step 32, determining, according to the location of the main segment character in the license plate area image, that the connected domain where the sub-segment character is located is located to the right of the main segment character.

It should be noted that, in this application, the order in which the connected domain where the sub-segment character is located is located on the left or the right side of the main segment character is not limited, and the sub-segment character may be determined to be on the left side to determine whether the sub-segment character is in the right state. On the side, you can also determine whether the sub-segment character is on the right side and then determine whether the sub-segment character is on the left side.

Since the sub-segment characters may only be located on the left or right side of the main segment character, it is impossible to be located at the left and right sides of the main segment character at the same time. Therefore, once it is determined that the connected field of the sub-segment character is located to the left or right of the main segment character, On the side, it is no longer necessary to continue to determine whether the sub-segment character is located on the other side of the main segment character, and sub-step 22 of determining the sub-segment region can be further performed.

Further, in a preferred embodiment of the present application, the sub-step 31 may specifically include:

Determining whether the height of the first area is consistent with the height of the main segment character; when the height of the first area is consistent with the height of the main segment character, determining that the first area is the sub-segment character a connected domain; wherein the first area is an area between a left side of the main section character and a distance from the left side to preset a third number of characters; or

Determining whether the height of the second area is consistent with the height of the main segment character; when the height of the second area is consistent with the height of the main segment character, determining that the second area is the sub-segment character a connected domain; wherein the second area is an area between a predetermined fourth number of characters from a left side of the main character character and a fifth number of characters preset by a distance from the left side;

When the height of the second area is inconsistent with the height of the main segment character, and is the first time determining whether the height of the second area is consistent with the height of the main segment character, inverting the second area Color, performing the determining whether the height of the second region is consistent with the height of the main segment character.

The preset third number of characters may be two characters, and the preset fourth number of characters may be three characters, and the preset fifth number of characters may be six characters.

It should be noted that, only when it is determined that the height of the second area is inconsistent with the height of the main segment character for the first time, it is necessary to invert the color in the second area, and perform another determination process for the second area. If the second judgment result for the second region is still that the height of the second region is inconsistent with the height of the main segment character, it indicates that the second region is not the connected domain in which the sub-segment character is located.

In this way, it can be determined whether there is a connected domain on the left side of the main segment character, and if there is a connected domain on the left side of the main segment character, the position of the connected domain relative to the main segment character can also be determined.

In a preferred embodiment of the present application, the sub-step 32 may specifically include:

Determining whether a lower bound of the third region is consistent with the main segment character, and a height of the third region is three-quarters of a height of the main segment character; if yes, determining that the third region is the a connected domain in which the sub-segment character is located; wherein the fourth area is preset from a sixth number of characters from a right side of the main segment character to a distance from the right side to preset a seventh number of characters Area between; or

Determining whether the height of the fourth area is consistent with the height of the main segment character; if yes, determining that the fourth area is a connected domain in which the sub-segment character is located; wherein the fourth area is a slave The right side of the main segment character is an area between a preset eighth number of characters and a distance from the right side preset by a ninth number of characters; or

Determining whether the height of the fifth area is consistent with the height of the main segment character; if yes, determining that the fifth area is a connected domain in which the sub-segment character is located; wherein the fifth area is a slave The right side of the main segment character is a region between a preset tenth number of characters and a distance from the right side to preset an eleventh number of characters.

The preset sixth number of characters may be one character, and the preset seventh number of characters may be three characters, and the preset eighth number of characters may be one character, and the preset ninth number of characters may be four characters. Character, the preset tenth number of characters can be four characters, and the eleventh number of characters can be eight characters by default.

In this way, it can be determined whether there is a connected domain on the right side of the main segment character, and if there is a connected domain on the right side of the main segment character, the position of the connected domain relative to the main segment character can also be determined.

For example, the license plate C1 and the license plate D1 in FIG. 2; the connected domain where the sub-segment characters in the license plate C1 are located in the first area on the left side of the main character 4297; the connected domain in which the sub-segment characters in the license plate D1 are located in the main segment The third area on the right side of the character 3890.

Next, in a preferred embodiment of the present application, the sub-step 23 may specifically include:

Determining, according to the preset first classification model, whether the sub-segment character exists in the sub-segment area;

If yes, determining, according to the preset second classification model, the sub-segment characters in the to-be-identified license plate in the sub-segment area;

If no, sub-step 21 is performed.

The preset first classification model and the second classification model can be trained according to any license plate style, for example, according to the license plate style of the members of the GCC countries in the UAE. The classification model may be a neural network model, or a support vector machine (SVM) classification model, a boost classification model, etc., and the specific form of the classification model is not limited in this application.

Specifically, the first classification model is used to determine whether there is a valid character in the sub-segment area, that is, whether there is a sub-segment character, and if there is a sub-segment character, the second classification model is used to identify the sub-segment character in the sub-segment area. .

It can be seen that the embodiment of the present application can determine the initial main segment character in the license plate to be identified in the acquired license plate area image of the license plate to be identified; next, determine whether the belonging character of the left end or the right end of the initial main segment character exists The character of the segment character; the character belonging to the sub-segment character at the left or right end of the initial main segment character is deleted, and the main segment character of the license plate to be identified is obtained; finally, the sub-segment in the license plate to be identified is determined according to the position of the main segment character character. In this way, the interference of the sub-segment characters that are tightly connected with the main segment character can be excluded, the accurate main segment character is obtained, and the sub-segment characters are determined according to the precise main segment character. Since the fixed template is not used in the embodiment of the present application, multiple types of single-layer license plates can be identified according to different application scenarios, and the scope of application is wide.

The embodiment of the present application also discloses a method for recognizing characters in a license plate. Referring to FIG. 6, FIG. 6 is still another flowchart of a method for recognizing characters in a license plate according to an embodiment of the present application, including the following steps:

Step 601: Acquire a scene image that includes a license plate to be identified; and determine a sequence of consecutive characters having the largest number of characters in the license plate area image as an initial main segment character in the license plate to be identified;

Step 602: Extract two characters from left to right from the initial main segment characters.

Step 603, it is determined whether the first character from left to right is smaller than the second character; if yes, step 606 is performed, if not, step 604 is performed;

Step 604, it is determined whether the first character is a letter; if yes, step 605 is performed; if not, step 606 is performed;

Step 605, determining that the first character belongs to the sub-segment character, and deleting the first character from the initial main segment character to obtain an accurate main segment character; performing step 610;

Specifically, the size of the first character can be determined, and the first character is re-identified to determine that the first character belongs to the sub-segment character; and the first character is deleted from the initial main segment character; Main segment character.

In practical applications, it can be initially determined that the license plate to be identified is a license plate of the Lebanese country.

Step 606: Extract, from the initial main segment character, a fourth character from left to right and a character after the fourth character;

Step 607, determining whether the fifth character and the character after the fifth character are smaller than the fourth character; if yes, the sub-segment character does not exist in the initial main segment character, if Otherwise, step 608 is performed;

Step 608, it is determined whether the fifth character and the character after the fifth character are letters; if yes, step 609 is performed; if not, the sub-segment character does not exist in the license plate to be identified;

Step 609, determining that the fifth character and the characters after the fifth character belong to the sub-segment character, and deleting the fifth character and the fifth character from the initial main segment character. Character, get the exact main segment character; perform step 610;

Specifically, the fifth character and the characters after the fifth character may be determined, and the fifth character and the characters after the fifth character are re-identified, and the fifth character and the characters after the fifth character are determined. It belongs to the sub-segment character; and, the fifth character and the character after the fifth character are deleted from the initial main segment character; the exact main segment character is obtained.

In practical applications, it can be initially determined that the license plate to be identified is a license plate of the Saudi state.

Step 610, it is determined whether the height of the first area is consistent with the height of the main segment character; if yes, step 616 is performed; if not, step 611 is performed;

The first area is an area between two characters from a left side of the main segment character to a distance from the left side.

Step 611, it is determined whether the height of the second area is consistent with the height of the main segment character; if yes, step 616 is performed; if not, step 612 is performed;

The second area is an area between three characters from the left side of the main segment character and six characters from the left side.

Step 612, it is determined whether it is the first judgment; if yes, the color in the second area is reversed, and the process returns to step 611; if not, step 613 is performed;

Step 613, it is determined whether the lower boundary of the third area is consistent with the main segment character, and the height of the third area is three-quarters of the height of the main segment character; if yes, step 616 is performed; Otherwise, step 614 is performed;

The fourth area is an area between one character from a right side of the main segment character and three characters from a distance from the right side.

Step 614, it is determined whether the height of the fourth area is consistent with the height of the main segment character; if yes, step 616 is performed; if no, step 615 is performed;

The fourth area is an area between a character from a right side of the main segment character and a distance of four characters from the right side.

Step 615, it is determined whether the height of the fifth area is consistent with the height of the main segment character; if yes, step 616 is performed; if not, the sub-segment character does not exist in the to-be-identified license plate;

The fifth area is an area between four characters from a right side of the main segment character and eight characters from the right side.

Step 616, determining a connected domain where the sub-segment character is located;

Step 617: Determine, in the connected domain, a sub-segment area where the sub-segment character is located;

The sub-segment area is a minimum circumscribed rectangle in the connected domain.

Step 618: Determine, according to the preset first classification model, whether the sub-segment character exists in the sub-segment area; if yes, perform step 619; if not, the sub-segment character does not exist in the to-be-identified license plate ;

Step 619: Determine, according to the preset second classification model, the sub-segment characters in the to-be-identified license plate in the sub-segment area.

It can be seen that the embodiment of the present application can identify the main segment character from the license plate to be identified. When the sub-segment character exists in the to-be-identified license plate, the sub-segment character is identified according to the position of the main segment character.

The embodiment of the present application further discloses a license plate type identification device. As shown in FIG. 7 , FIG. 7 is a structural diagram of a license plate type identification device according to an embodiment of the present application. The device includes: an acquisition unit 701, a determining unit 702, a determining unit 703, a deleting unit 704, and a second determining unit 705;

The acquiring unit 701 is configured to acquire an image of a license plate area of the license plate to be identified;

The first determining unit 702 is configured to determine a sequence of consecutive characters having the largest number of characters in the license plate area image as an initial main segment character in the to-be-identified license plate;

The determining unit 703 is configured to determine, according to the preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character;

The deleting unit 704 is configured to delete a character belonging to a sub-segment character located at a left end or a right end of the initial main segment character to obtain a main segment character in the to-be-identified license plate;

The second determining unit 705 is configured to determine a sub-segment character in the license plate to be identified according to the location of the main segment character in the license plate area image.

It can be seen that the apparatus embodiment of the present application can obtain the license plate area corresponding to the license plate to be identified in the scene image; then, determine the character sequence and the background color in the license plate to be identified in the license plate area; next, according to the preset rule, the license plate The special pattern area corresponding to the license plate to be identified is determined in the area; finally, the license plate type of the license plate to be identified is determined according to the character sequence and the background color in the license plate to be identified, and the special pattern area. In this way, the embodiment of the present application can identify the license plate type corresponding to the license plate including the special pattern, and the application range is wider.

The embodiment of the present application further discloses a license plate type identification device. As shown in FIG. 8 , FIG. 8 is another structural diagram of a license plate type identification device according to an embodiment of the present application. The device includes: an acquisition unit 701, a first determining unit 702, a determining unit 703, a deleting unit 704, and a second determining unit 705;

The determining unit 703 includes: an extracting subunit 801, a determining subunit 802, a first determining subunit 803, and a second determining subunit 804;

The extracting subunit 801 is configured to extract a first preset number of characters from the left end of the initial main segment character or a second preset number of characters from the right end;

The determining sub-unit 802 is configured to determine whether the character sizes in the first preset number of characters or the second preset number of characters are the same;

The first determining sub-unit 803 is configured to determine, in the first preset number of characters, that the characters in the first preset number of characters or the second preset number of characters are different in size Determining, by the size of the first smaller character, or the size of the second smaller one of the second predetermined number of characters; determining whether the first smaller character or the second smaller character is a letter; Determining that the first smaller character or the second smaller character belongs to the sub-segment character;

The second determining subunit 804 is configured to: if the first preset number of characters or the second preset number of characters have the same size, or the first smaller character or the first If the second smaller character is not a letter, it is determined that there is no character belonging to the sub-segment character in the character at the left or right end of the initial main segment character.

The second determining unit 705 includes: a third determining subunit 805, a fourth determining subunit 806, and a fifth determining subunit 807;

The third determining sub-unit 805 is configured to determine, according to a location of the main segment character in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image;

The fourth determining sub-unit 806 is configured to determine, in the connected domain, a sub-segment area where the sub-segment character is located;

The fifth determining sub-unit 807 is configured to determine, in the sub-segment area, the sub-segment characters in the license plate to be identified according to a preset classification model.

The third determining subunit 805 includes: a sixth determining subunit 808 and a seventh determining subunit 809;

The sixth determining sub-unit 808 is configured to determine, according to the location of the main segment character in the license plate area image, the connected segment where the sub-segment character is located, where the sub-segment character is located in the main segment character Left side; or

The seventh determining sub-unit 809 is configured to determine, according to the location of the main segment character in the license plate area image, the connected segment where the sub-segment character is located, where the sub-segment character is located in the main segment character Right.

It can be seen that the embodiment of the present application can identify the license plate type corresponding to the license plate including the special pattern, and the application range is wider.

The embodiment of the present application further discloses a storage medium for storing executable code, and the executable code is configured to perform the following steps at runtime:

Obtaining an image of the license plate area of the license plate to be identified;

Determining, as the initial main segment character in the license plate to be identified, a continuous character sequence having the largest number of characters in the license plate area image;

Determining, according to a preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character;

Deleting a character belonging to a sub-segment character at a left end or a right end of the initial main segment character to obtain a main segment character in the to-be-identified license plate;

The sub-segment characters in the license plate to be identified are determined according to the position of the main segment character in the license plate area image.

It can be seen that the storage medium disclosed in the embodiment of the present application can determine the initial main segment character in the license plate to be identified in the obtained license plate area image of the license plate to be identified; next, determine the left end or the right end character of the initial main segment character. Whether there is a character belonging to the sub-segment character; the character belonging to the sub-segment character at the left end or the right end of the initial main segment character is deleted, and the main segment character of the license plate to be recognized is obtained; finally, the position to be identified is determined according to the position of the main segment character Sub-segment characters in the license plate. In this way, the interference of the sub-segment characters that are tightly connected with the main segment character can be excluded, the accurate main segment character is obtained, and the sub-segment characters are determined according to the precise main segment character. Since the fixed template is not used in the embodiment of the present application, multiple types of single-layer license plates can be identified according to different application scenarios, and the scope of application is wide.

Optionally, the step of determining, according to the preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character, includes:

Extracting a first preset number of characters from the left end of the initial main segment character or extracting a second preset number of characters from the right end;

Determining whether the character sizes in the first preset number of characters or the second preset number of characters are the same;

If the size of the first preset number of characters or the second preset number of characters is different, determining a size of the first smaller number of the first preset number of characters, or a size of a second smaller one of the second predetermined number of characters; determining whether the first smaller character or the second smaller character is a letter; if the first smaller character or the second comparison The small character is a letter, and it is determined that the first smaller character or the second smaller character belongs to the sub-segment character;

If the characters in the first preset number of characters or the second preset number of characters are the same, or the first smaller character and the second smaller character are not letters, the determining is located There are no characters belonging to the sub-segment characters in the characters at the left or right end of the initial main segment character.

Optionally, the step of determining the sub-segment characters in the license plate to be identified according to the location of the main segment character in the license plate area image includes:

Determining, according to a location of the main segment character in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image;

Determining, in the connected domain, a sub-segment area in which the sub-segment character is located;

Determining the sub-segment characters in the license plate to be identified in the sub-segment area according to a preset classification model.

Optionally, the step of determining, according to the location of the main segment character in the license plate area image, the connected domain of the sub-segment character in the license plate area image, including:

Determining, according to a location of the main segment character in the license plate area image, a connected domain where the sub-segment character is located to a left side of the main segment character; or

And determining, according to the location of the main segment character in the license plate area image, that the connected domain where the sub-segment character is located is located to the right of the main segment character.

Optionally, the step of determining that the connected domain where the sub-segment character is located is located on a left side of the main segment character according to a location of the main segment character in the license plate area image ,include:

Determining whether the height of the first area is consistent with the height of the main segment character; when the height of the first area is consistent with the height of the main segment character, determining that the first area is the sub-segment character a connectivity domain; wherein the first region is an area between a left side of the main segment character and a third number of characters from the left side; or

Determining whether the height of the second area is consistent with the height of the main segment character; when the height of the second area is consistent with the height of the main segment character, determining that the second area is the sub-segment character a connectivity domain; wherein the second region is an area between a fourth number of characters from a left side of the main segment character and a fifth number of characters from the left side distance;

Optionally, the step of determining, according to the location of the main segment character in the license plate area image, that the sub-segment character of the connected domain where the sub-segment character is located is located on a right side of the main segment character, include:

Determining whether a lower bound of the third region is consistent with the main segment character, and a height of the third region is three-quarters of a height of the main segment character; if yes, determining that the third region is the a connected domain in which the sub-segment character is located; wherein the fourth region is between a sixth number of characters from a right side of the main segment character and a seventh number of characters from the right side Area; or

Determining whether the height of the fourth area is consistent with the height of the main segment character; if yes, determining that the fourth area is a connected domain in which the sub-segment character is located; wherein the fourth area is a slave The right side of the main segment character is an area between a preset eighth number of characters and a preset ninth number of characters from the right side; or

Determining whether the height of the fifth area is consistent with the height of the main segment character; if yes, determining that the fifth area is a connected domain in which the sub-segment character is located; wherein the fifth area is a slave The right side of the main segment character is a region between a preset tenth number of characters and a predetermined eleventh number of characters from the right side.

Optionally, the step of determining, according to the preset classification model, the sub-segment characters in the to-be-identified license plate in the sub-segment area, including:

If not, performing the determining according to the location of the main segment character in the license plate area image to determine a connected domain in which the sub-segment character is located in the license plate area image.

It can be seen that the storage medium disclosed in the present application is capable of recognizing a license plate type corresponding to a license plate including a special pattern, and has a wide application range.

The embodiment of the present application further discloses an application for performing the following steps at runtime:

It can be seen that the application program disclosed in the embodiment of the present application can determine the initial main segment character in the license plate to be identified in the obtained license plate area image of the license plate to be identified; next, determine the left end or the right end character of the initial main segment character. Whether there is a character belonging to the sub-segment character; the character belonging to the sub-segment character at the left end or the right end of the initial main segment character is deleted, and the main segment character of the license plate to be recognized is obtained; finally, the position to be identified is determined according to the position of the main segment character Sub-segment characters in the license plate. In this way, the interference of the sub-segment characters that are tightly connected with the main segment character can be excluded, the accurate main segment character is obtained, and the sub-segment characters are determined according to the precise main segment character. Since the fixed template is not used in the embodiment of the present application, multiple types of single-layer license plates can be identified according to different application scenarios, and the scope of application is wide.

It can be seen that the application disclosed in the present application can recognize the license plate type corresponding to the license plate including the special pattern, and has a wide application range.

An embodiment of the present application further discloses an apparatus for recognizing characters in a license plate. Referring to FIG. 9, FIG. 9 is a schematic diagram of an apparatus for recognizing characters in a license plate according to an embodiment of the present application. As shown in Figure 9, the device for identifying characters in the license plate includes: a processor 901 and a memory 902;

The memory 902 is configured to store executable program code;

The processor 901 is configured to run a program corresponding to the executable program code by reading executable program code stored in the memory 902 to perform the following steps:

It can be seen that the device for recognizing characters in the license plate disclosed in the embodiment of the present application can determine the initial main segment character in the license plate to be identified in the acquired license plate region image of the license plate to be identified; and then, determine the left end of the initial main segment character. Or whether the character belonging to the sub-segment character exists in the character at the right end; the character belonging to the sub-segment character at the left or right end of the initial main segment character is deleted, and the main segment character of the license plate to be recognized is obtained; finally, according to the position of the main segment character , determine the sub-segment characters in the license plate to be identified. In this way, the interference of the sub-segment characters that are tightly connected with the main segment character can be excluded, the accurate main segment character is obtained, and the sub-segment characters are determined according to the precise main segment character. Since the fixed template is not used in the embodiment of the present application, multiple types of single-layer license plates can be identified according to different application scenarios, and the scope of application is wide.

It can be seen that the device for recognizing characters in the license plate disclosed in the present application can recognize the license plate type corresponding to the license plate including the special pattern, and has a wide application range.

It should be noted that, in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply such entities or operations. There is any such actual relationship or order between them. Furthermore, the term "comprises" or "comprises" or "comprises" or any other variations thereof is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device that comprises a plurality of elements includes not only those elements but also Other elements, or elements that are inherent to such a process, method, item, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

The various embodiments in the present specification are described in a related manner, and the same or similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.

The above description is only the preferred embodiment of the present application, and is not intended to limit the scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application are included in the scope of the present application.

Claims

A method for recognizing characters in a license plate, the method comprising:

Obtaining an image of the license plate area of the license plate to be identified;

Determining, as the initial main segment character in the license plate to be identified, a continuous character sequence having the largest number of characters in the license plate area image;

Determining, according to a preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character;

Deleting a character belonging to a sub-segment character at a left end or a right end of the initial main segment character to obtain a main segment character in the to-be-identified license plate;

The sub-segment characters in the license plate to be identified are determined according to the position of the main segment character in the license plate area image.
The method according to claim 1, wherein the step of determining, according to the preset sub-segment character, whether there is a character belonging to the sub-segment character in the character at the left end or the right end of the initial main segment character, include:

Extracting a first preset number of characters from the left end of the initial main segment character or extracting a second preset number of characters from the right end;

Determining whether the character sizes in the first preset number of characters or the second preset number of characters are the same;

If the size of the first preset number of characters or the second preset number of characters is different, determining a size of the first smaller number of the first preset number of characters, or a size of a second smaller one of the second predetermined number of characters; determining whether the first smaller character or the second smaller character is a letter; if the first smaller character or the second comparison The small character is a letter, and it is determined that the first smaller character or the second smaller character belongs to the sub-segment character;

If the characters in the first preset number of characters or the second preset number of characters are the same, or the first smaller character and the second smaller character are not letters, the determining is located There are no characters belonging to the sub-segment characters in the characters at the left or right end of the initial main segment character.
The method according to claim 1, wherein the step of determining the sub-segment characters in the license plate to be identified according to the location of the main segment character in the license plate area image comprises:

Determining, according to a location of the main segment character in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image;

Determining, in the connected domain, a sub-segment area in which the sub-segment character is located;

Determining the sub-segment characters in the license plate to be identified in the sub-segment area according to a preset classification model.
The method according to claim 3, wherein said step of determining a connected domain in which said sub-segment character is located in said license plate area image is based on a position of said main segment character in said license plate area image ,include:

Determining, according to a location of the main segment character in the license plate area image, a connected domain where the sub-segment character is located to a left side of the main segment character; or

And determining, according to the location of the main segment character in the license plate area image, that the connected domain where the sub-segment character is located is located to the right of the main segment character.
The method according to claim 4, wherein said determining, according to a position of said main segment character in said license plate region image, a connected domain in which said sub-segment character is located is located at said sub-segment character The steps to the left of the main segment character include:

Determining whether the height of the first area is consistent with the height of the main segment character; when the height of the first area is consistent with the height of the main segment character, determining that the first area is the sub-segment character a connectivity domain; wherein the first region is an area between a left side of the main segment character and a third number of characters from the left side; or

Determining whether the height of the second area is consistent with the height of the main segment character; when the height of the second area is consistent with the height of the main segment character, determining that the second area is the sub-segment character a connectivity domain; wherein the second region is an area between a fourth number of characters from a left side of the main segment character and a fifth number of characters from the left side distance;

When the height of the second area is inconsistent with the height of the main segment character, and is the first time determining whether the height of the second area is consistent with the height of the main segment character, inverting the second area Color, performing the determining whether the height of the second region is consistent with the height of the main segment character.
The method according to claim 4, wherein said determining, according to a position of said main segment character in said license plate region image, said connected sub-segment character in which said sub-segment character is located is located in said method The steps to the right of the main paragraph character, including:

Determining whether a lower bound of the third region is consistent with the main segment character, and a height of the third region is three-quarters of a height of the main segment character; if yes, determining that the third region is the a connected domain in which the sub-segment character is located; wherein the fourth region is between a sixth number of characters from a right side of the main segment character and a seventh number of characters from the right side Area; or

Determining whether the height of the fourth area is consistent with the height of the main segment character; if yes, determining that the fourth area is a connected domain in which the sub-segment character is located; wherein the fourth area is a slave The right side of the main segment character is an area between a preset eighth number of characters and a preset ninth number of characters from the right side; or

Determining whether the height of the fifth area is consistent with the height of the main segment character; if yes, determining that the fifth area is a connected domain in which the sub-segment character is located; wherein the fifth area is a slave The right side of the main segment character is a region between a preset tenth number of characters and a predetermined eleventh number of characters from the right side.
The method according to claim 3, wherein the step of determining the sub-segment characters in the license plate to be identified in the sub-segment area according to a preset classification model comprises:

Determining, according to the preset first classification model, whether the sub-segment character exists in the sub-segment area;

If yes, determining, according to the preset second classification model, the sub-segment characters in the to-be-identified license plate in the sub-segment area;

If not, performing the determining according to the location of the main segment character in the license plate area image to determine a connected domain in which the sub-segment character is located in the license plate area image.
A device for recognizing characters in a license plate, characterized in that the device comprises:

An obtaining unit, configured to obtain an image of a license plate area of the license plate to be identified;

a first determining unit, configured to determine a continuous character sequence having the largest number of characters in the license plate area image as an initial main segment character in the to-be-identified license plate;

a determining unit, configured to determine, according to the preset sub-segment character, whether a character belonging to the sub-segment character exists in a character located at a left end or a right end of the initial main segment character;

a deleting unit, configured to delete a character belonging to a sub-segment character located at a left end or a right end of the initial main segment character to obtain a main segment character in the to-be-identified license plate;

And a second determining unit, configured to determine a sub-segment character in the license plate to be identified according to a location of the main segment character in the license plate area image.
The apparatus according to claim 8, wherein the determining unit comprises: an extracting subunit, a determining subunit, a first determining subunit, and a second determining subunit;

The extracting subunit is configured to extract a first preset number of characters from a left end of the initial main segment character or a second preset number of characters from a right end;

The determining subunit is configured to determine whether the character sizes in the first preset number of characters or the second preset number of characters are the same;

Determining, by the first determining subunit, a first predetermined number of characters in the first preset number of characters or the second preset number of characters a size of a smaller character, or a size of a second smaller one of the second predetermined number of characters; determining whether the first smaller character or the second smaller character is a letter; Determining that the first smaller character or the second smaller character belongs to the sub-segment character;

The second determining subunit is configured to: if the first preset number of characters or the second preset number of characters have the same size, or the first smaller character and the second If the smaller character is not a letter, it is determined that there is no character belonging to the sub-segment character in the character at the left or right end of the initial main segment character.
The apparatus according to claim 8, wherein the second determining unit comprises: a third determining subunit, a fourth determining subunit, and a fifth determining subunit;

The third determining subunit is configured to determine, according to a location of the main segment character in the license plate area image, a connected domain in which the sub-segment character is located in the license plate area image;

The fourth determining subunit is configured to determine, in the connected domain, a sub-segment area where the sub-segment character is located;

The fifth determining subunit is configured to determine, in the sub-segment area, the sub-segment characters in the license plate to be identified according to a preset classification model.
The apparatus according to claim 10, wherein the third determining subunit comprises: a sixth determining subunit and a seventh determining subunit;

The sixth determining subunit is configured to determine, according to a location where the main segment character is located in the license plate area image, a connected domain where the sub-segment character is located is located to a left side of the main segment character; or

The seventh determining subunit is configured to determine, according to the location of the main segment character in the license plate area image, that the connected domain where the sub-segment character is located is located to the right of the main segment character.
The apparatus according to claim 11, wherein said sixth determining subunit comprises: an eighth determining subunit, a ninth determining subunit, and an executing subunit;

The eighth determining subunit is configured to determine whether the height of the first area is consistent with the height of the main segment character; and when the height of the first area is consistent with the height of the main segment character, determining the first An area is a connected domain in which the sub-segment character is located; wherein the first area is an area between a left side of the main-segment character and a third-numbered character from the left side; or

The ninth determining subunit is configured to determine whether the height of the second area is consistent with the height of the main segment character; and when the height of the second area is consistent with the height of the main segment character, determining the The second area is a connected domain in which the sub-segment character is located; wherein the second area is a preset fourth number of characters from a left side of the main segment character to a fifth distance from the left side distance The area between a number of characters;

The execution subunit is configured to: when the height of the second area is inconsistent with the height of the main segment character, and determine whether the height of the second area is consistent with the height of the main segment character for the first time, Turning the color in the second area, performing the determining whether the height of the second area is consistent with the height of the main segment character.
The apparatus according to claim 11, wherein said seventh determining subunit comprises: a tenth determining subunit, an eleventh determining subunit, and a twelfth determining subunit;

The tenth determining subunit is configured to determine whether a lower bound of the third area is consistent with the main segment character, and a height of the third area is three quarters of a height of the main segment character; if yes, Determining that the third area is a connected domain in which the sub-segment character is located; wherein the fourth area is a preset sixth sixth number of characters from the right side of the main segment character to the right side The area between the preset seventh number of characters; or

The eleventh determining subunit is configured to determine whether the height of the fourth area is consistent with the height of the main segment character; if yes, determining that the fourth area is a connected domain where the sub-segment character is located; The fourth area is an area between an eighth number of characters from a right side of the main character character and a ninth number of characters preset to the right side distance; or

The twelfth determining subunit is configured to determine whether the height of the fifth area is consistent with the height of the main segment character; if yes, determining that the fifth area is a connected domain in which the sub-segment character is located; The fifth area is an area between a preset tenth number of characters from a right side of the main segment character and an eleventh number of characters preset from the right side distance.
The apparatus according to claim 10, wherein said fifth determining subunit comprises: a thirteenth determining subunit, a fourteenth determining subunit, and a fifteenth determining subunit;

The thirteenth determining subunit is configured to determine, according to the preset first classification model, whether the sub-segment character exists in the sub-segment area;

The fourteenth determining subunit is configured to determine, in the sub-segment area, the to-be-identified license plate according to a preset second classification model if the sub-segment character exists in the sub-segment area The sub-segment character;

The fifteenth determining subunit, configured to determine, according to a location of the main segment character in the license plate area image, if the sub-segment character does not exist in the sub-segment area, The connected domain in which the sub-segment character is located in the license plate area image.
A storage medium for storing executable code for performing a method of recognizing a character in a license plate according to any one of claims 1-7 at runtime.
An application for performing a method of recognizing a character in a license plate according to any one of claims 1-7 at runtime.
A device for recognizing characters in a license plate, comprising: a processor and a memory;

The memory is for storing executable program code;

The processor, configured to execute a program corresponding to the executable program code by reading executable program code stored in the memory to perform the identification of the license plate according to any one of claims 1-7 The method of characters.