Wafer OCR (Optical Character Recognition) method and device based on image enhancement

Abstract

The invention provides a wafer OCR (Optical Character Recognition) method and device based on image enhancement, and the method comprises the following steps: obtaining a character recognition region image on a wafer; sequentially carrying out image equalization, image filtering, image overturning, dynamic threshold segmentation and opening and closing operation processing on the character recognition area image so as to enhance the image and obtain an enhanced recognition area image; determining a wafer OCR character region in the enhanced recognition region image by using opening and closing operation, and extracting the wafer OCR character region; extracting each character in the OCR character area of the wafer; and recognizing the characters in sequence. According to the technical scheme, the problem that character templates need to be reset for different batches of wafers can be effectively solved, and the recognition efficiency is improved. In addition, through a large amount of image enhancement, the influence of uneven illumination and large noise on recognition is effectively reduced, and meanwhile the recognition speed is high.

Description

Technical Field

[0001] The present invention belongs to the technical field of wafer OCR recognition, and in particular relates to a wafer OCR recognition method and a recognition device based on image enhancement. Background Art

[0002] Wafer processing is a very important part of the chip production process. Each wafer has a unique number (Wafer ID), which is the wafer's OCR (Chinese name is identification code). Through OCR, the production information of the wafer can be found. In the front-end process, the wafer's OCR is usually on the back of the wafer; in the back-end packaging and testing stage, after the wafer is tested by needle, the corresponding Map information will be written into the wafer's OCR. Through the wafer OCR, we can know which DIEs in the wafer are qualified, providing information assistance for subsequent packaging and testing.

[0003] Currently, template matching can be used to extract the OCR character area on the wafer and then recognize it. For wafers of different batches, the OCR characters are different, so different character templates need to be set, resulting in low recognition efficiency. Summary of the invention

[0004] Therefore, the present invention provides a wafer OCR recognition method and a recognition device based on image enhancement, which can solve the technical problem in the prior art that different batches of wafers need to reset character templates, resulting in low recognition efficiency.

[0005] In order to solve the above problems, the present invention provides a wafer OCR recognition method based on image enhancement, which comprises the following steps:

[0006] Acquire a character recognition area image on a wafer; wherein the character recognition area image is a part of the wafer image, and the character recognition area image contains the OCR of the wafer;

[0007] The character recognition area image is subjected to image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operation processing in sequence to enhance the image and obtain an enhanced recognition area image;

[0008] Using the opening and closing operation again to determine the wafer OCR character area within the enhanced recognition area image, and extracting the wafer OCR character area;

[0009] Extract each character in the wafer OCR character area;

[0010] Recognize each character in turn.

[0011] In some implementations, acquiring the character recognition area image on the wafer specifically includes:

[0012] Acquire wafer images;

[0013] A recognition frame is set so that the OCR in the wafer image is located in the recognition frame, and the area in the recognition frame on the wafer image is extracted to obtain the character recognition area image.

[0014] In some implementations, extracting each character in the wafer OCR character area specifically includes:

[0015] Threshold segmentation is performed on the wafer OCR character area to obtain different connected domains;

[0016] Structural screening is performed on each of the connected domains to screen out character connected domains in the connected domains to obtain each character.

[0017] In some embodiments, the structural screening comprises: area comparison and / or length comparison and / or width comparison.

[0018] In some implementations, recognizing each character in turn specifically includes:

[0019] Perform recognition training on each character of wafer OCR respectively to obtain a recognition model for each character;

[0020] Each character is recognized in turn according to the recognition model.

[0021] The present invention also provides a wafer OCR recognition device based on image enhancement, which includes a character recognition area acquisition module, a recognition area acquisition module, a preprocessing module, a wafer OCR extraction module, a character extraction module and a recognition module;

[0022] The character recognition area acquisition module is used to acquire a character recognition area image on a wafer; wherein the character recognition area image is a part of the wafer image, and the character recognition area image contains the OCR of the wafer;

[0023] The preprocessing module is used to perform image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operation processing on the character recognition image in sequence to enhance the image and obtain an enhanced recognition area image;

[0024] The wafer OCR extraction module is used to determine the wafer OCR character area in the enhanced recognition area image again by using the opening and closing operation, and extract the wafer OCR character area;

[0025] The character extraction module is used to extract each character in the wafer OCR character area;

[0026] The recognition module is used to recognize each character in turn.

[0027] The wafer OCR recognition method and recognition device based on image enhancement provided by the present invention have the following beneficial effects:

[0028] 1. The technical solution of the present invention directly extracts the character recognition area on the wafer through the recognition frame, and then repeatedly enhances the character recognition area by using the image enhancement method to determine the wafer OCR character area and extract the wafer OCR character area. Since there is no need to set a character template, it can effectively solve the problem of needing to reset the character template for different batches of wafers, thereby improving the recognition efficiency. In addition, after a large amount of image enhancement, the impact of uneven lighting and high noise on recognition is effectively reduced, and the recognition speed is very fast. The recognition method of the present invention also has the function of training unfamiliar characters, and is more applicable.

[0029] 2. Use the recognition frame method to quickly extract the OCR area on the wafer image. The recognition range is wide and there is no need to locate the wafer OCR character area, which can improve the recognition efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. The drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0031] Figure 1 It is a flow chart of a wafer OCR recognition method based on image enhancement of the present invention;

[0032] Figure 2 It is a schematic diagram of the wafer picture;

[0033] Figure 3 It is a schematic diagram of the character recognition area;

[0034] Figure 4 It is a schematic diagram of image processing and feature enhancement;

[0035] Figure 5 It is a schematic diagram of extracting character areas;

[0036] Figure 6 It is a schematic diagram of wafer OCR character recognition. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0039] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] Unless otherwise specified, the relative arrangement of the components and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that for ease of description, the structures, proportions, sizes, etc. shown in the drawings are only used to match the contents disclosed in the specification, so that people familiar with this technology can understand and read, and are not used to limit the limiting conditions that can be implemented in the present invention. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. The techniques, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the techniques, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, not as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0041] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0042] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0043] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0044] See also Figure 1-6 As shown, according to an embodiment of the present invention, a wafer OCR recognition method based on image enhancement is provided, which includes the following steps:

[0045] Step S1: Acquire a character recognition area image on a wafer, wherein the character recognition area image is a part of the wafer image, and the character recognition area image includes the OCR of the wafer.

[0046] It should be noted here that: in order to ensure the recognition accuracy of subsequent wafer OCR and improve the recognition efficiency, the character recognition area on the wafer should be as small as possible on the basis of including the wafer OCR. In a specific application example, the character recognition area is a rectangular area, and accordingly, the character recognition area image is a rectangular image.

[0047] In order to obtain the character recognition area image on the wafer, the following method can be used: Figure 2 As shown, a wafer image is acquired; Figure 3 As shown, a recognition frame is set so that the OCR in the wafer image is located in the recognition frame, and the area in the recognition frame on the wafer image is extracted to obtain the character recognition area image. Specifically, the feeding mechanism can ensure that the OCR on the wafer can be located in the recognition frame when the wafer is fed into the set shooting position.

[0048] The area within the recognition frame on the wafer image is the character recognition area, and the character recognition area image is obtained by extracting the character recognition area.

[0049] The above-mentioned method of using a recognition frame to quickly extract the OCR area on the wafer image has a wide recognition range and does not require positioning of the wafer OCR character area, which can improve recognition efficiency.

[0050] It should be noted here that the wafer image can be acquired by using an industrial camera, a zoom lens and a strip light to form an acquisition module. The quality of the acquired image can be guaranteed by using an industrial camera, a zoom lens and a strip light to form an acquisition module. Secondly, by adjusting the brightness of the light source, it can be applied to most wafer image acquisition scenarios.

[0051] Step S2: Figure 4 As shown, the character recognition area image is subjected to image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operation processing in sequence to enhance the image and obtain an enhanced recognition area image.

[0052] The OCR characters on the wafers are different, and there are different degrees of wear and tear during the processing and testing process, which increases the difficulty of recognition. In step S2, by performing image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operations on the image in sequence, the contrast of the characters can be increased, the noise in the image can be reduced, and the image can be enhanced.

[0053] It should be noted here that: the above-mentioned image equalization is to improve the contrast of the image; image filtering is mainly used to remove noise in the image; image flipping can enhance the details of the dark area of ​​the image and improve sharpness and contrast; dynamic threshold segmentation extracts features within the corresponding grayscale value range; closing operation is to connect the backup features into one area.

[0054] Step S3: Figure 5 As shown, the opening and closing operation is used again to determine the wafer OCR character area within the enhanced recognition area image, and the wafer OCR character area is extracted.

[0055] Among them, using the opening and closing operation again will form a large connected domain including the characters, and obtaining the sub-connected domain inside it can separate the characters. Using the opening and closing operation again to determine the wafer OCR character area can effectively reduce the impact of noise points around the characters on the recognition algorithm and improve the accuracy of recognition.

[0056] Step S4: Figure 6 As shown, each character in the wafer OCR character area is extracted.

[0057] Specifically, the extraction of each character in the wafer OCR character area can be achieved by the following method: threshold segmenting the wafer OCR character area to obtain different connected domains, and structurally screening each of the connected domains to screen out the character connected domains in the connected domain to obtain each character.

[0058] Among them, some of the connected domains are character connected domains, and some are non-character connected domains. The character connected domains in each connected domain can be screened out by structural screening to obtain each character.

[0059] In a specific application example, the above-mentioned structural screening may include: area comparison and / or length comparison and / or width comparison. Specifically, by comparing the area of ​​each connected domain with a preset area range value, and / or comparing the length of each connected domain with a preset length range value, and / or comparing the width of each connected domain with a preset width range value, if the area of ​​the connected domain is within the preset area range value, and / or the length of the connected domain is within the preset length range value, and / or the width of the connected domain is within the preset width range value, then the connected domain is the desired character connected domain, that is, the connected domain is screened out.

[0060] Step S5: recognize each character in turn.

[0061] The recognition of each character in sequence may be performed in the following manner: each character of the wafer OCR is trained for recognition respectively to obtain a recognition model of each character, and each character is recognized in sequence according to the recognition model.

[0062] It should be noted that: each character can be trained by character set, and the specific recognition training method is prior art and will not be described here. If an unfamiliar character is to be recognized, the character can be added to the character set for training and the recognition model can be updated.

[0063] The wafer OCR recognition method of the present invention directly extracts the character recognition area on the wafer through the recognition frame, and then repeatedly enhances the character recognition area by using the image enhancement method to determine the wafer OCR character area and extract the wafer OCR character area. Since there is no need to set a character template, the problem of needing to reset the character template for different batches of wafers can be effectively solved, thereby improving the recognition efficiency. In addition, after a large amount of image enhancement, the influence of uneven lighting and large noise on recognition is effectively reduced, and the recognition speed is very fast. The recognition method of the present invention also has a training function for unfamiliar characters, and is more applicable.

[0064] The present invention also provides a wafer OCR recognition device based on image enhancement, which includes a character recognition area acquisition module, a recognition area acquisition module, a preprocessing module, a wafer OCR extraction module, a character extraction module and a recognition module.

[0065] Among them, the character recognition area acquisition module is used to obtain the character recognition area image on the wafer; the character recognition area image is a part of the wafer image, and the character recognition area image contains the OCR of the wafer. The preprocessing module is used to perform image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operations on the character recognition image in sequence to enhance the image and obtain an enhanced recognition area image. The wafer OCR extraction module is used to use the opening and closing operation again to determine the wafer OCR character area in the enhanced recognition area image, and extract the wafer OCR character area. The character extraction module is used to extract each character in the wafer OCR character area. The recognition module is used to recognize each character in turn.

[0066] The wafer OCR recognition device of the present invention can effectively solve the problem that different batches of wafers need to reset the character template, thereby improving the recognition efficiency. In addition, after a large amount of image enhancement, the influence of uneven illumination and large noise on recognition is effectively reduced, and the recognition speed is very fast. The recognition method of the present invention also has the function of training unfamiliar characters, and is more applicable.

[0067] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A wafer OCR recognition method based on image enhancement, characterized in that: The following steps are involved: Acquire a character recognition area image on a wafer; wherein the character recognition area image is a part of the wafer image, and the character recognition area image contains the OCR of the wafer; The character recognition area image is subjected to image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operation processing in sequence to enhance the image and obtain an enhanced recognition area image; Using the opening and closing operation again to determine the wafer OCR character area within the enhanced recognition area image, and extracting the wafer OCR character area; Extract each character in the wafer OCR character area; Recognize each character in turn.

2. The wafer OCR recognition method based on image enhancement according to claim 1, characterized in that: The obtaining of the character recognition area image on the wafer specifically includes: Acquire wafer images; A recognition frame is set so that the OCR in the wafer image is located in the recognition frame, and the area in the recognition frame on the wafer image is extracted to obtain the character recognition area image.

3. The wafer OCR recognition method based on image enhancement according to claim 1, characterized in that: The extracting of each character in the wafer OCR character area specifically includes: Threshold segmentation is performed on the wafer OCR character area to obtain different connected domains; Structural screening is performed on each of the connected domains to screen out character connected domains in the connected domains to obtain each character.

4. The wafer OCR recognition method based on image enhancement according to claim 3 is characterized in that: The structural screening includes: area comparison and / or length comparison and / or width comparison.

5. The wafer OCR recognition method based on image enhancement according to claim 1, characterized in that: Each character is recognized in turn, including: Perform recognition training on each character of wafer OCR respectively to obtain a recognition model for each character; Each character is recognized in turn according to the recognition model.

6. A wafer OCR recognition device based on image enhancement, characterized in that: It includes a character recognition area acquisition module, a recognition area acquisition module, a pre-processing module, a wafer OCR extraction module, a character extraction module and a recognition module; The character recognition area acquisition module is used to acquire a character recognition area image on a wafer; wherein the character recognition area image is a part of the wafer image, and the character recognition area image contains the OCR of the wafer; The preprocessing module is used to perform image equalization, image filtering, image flipping, dynamic threshold segmentation and opening and closing operation processing on the character recognition image in sequence to enhance the image and obtain an enhanced recognition area image; The wafer OCR extraction module is used to determine the wafer OCR character area in the enhanced recognition area image again by using the opening and closing operation, and extract the wafer OCR character area; The character extraction module is used to extract each character in the wafer OCR character area; The recognition module is used to recognize each character in turn.

Images