WO2015096462A1

WO2015096462A1 - Method and system for focused display of 2-dimensional bar code

Info

Publication number: WO2015096462A1
Application number: PCT/CN2014/082081
Authority: WO
Inventors: 付仲平; 袁永贵; 汪雪林
Original assignee: 北京握奇智能科技有限公司
Priority date: 2013-12-24
Filing date: 2014-07-11
Publication date: 2015-07-02
Also published as: CN103729610B; CN103729610A

Abstract

Disclosed in the present invention are a method and system for focused display of a 2-dimensional bar code. At first, a 2-dimensional bar code image is obtained via a camera of a photographing device, and then the key information of a 2-dimensional bar code in the 2-dimensional bar code image is extracted, the proportional relation between the resolution of the camera of the photographing device and the resolution of a display area, which is used for displaying the outline of a photographed object, in a display screen is obtained, the coordinates of the key information of the 2-dimensional bar code image in a camera imaging coordinate system is proportionally mapped to the coordinates in a display screen coordinate system according to the proportional relation, and finally, information concerning the outline of the 2-dimensional bar code image is rebuilt according to the mapped key information of the 2-dimensional bar code in the 2-dimensional bar code image, and sent to the display screen for display purposes. According to the method and system disclosed in the present invention, an abstract analysis of the characteristic information of a scanned target is performed, and information concerning the outline of the target is extracted and restored to achieve a real-time feedback of view-finding locations, as a result, the dependency on high-resolution display equipment is no longer present; in addition, the method and system are particularly applicable for 2-dimensional bar code scanning equipment on which a low-resolution display screen is employed.

Description

Two-dimensional code focusing display method and system

Technical field

The invention belongs to the technical field of image processing, and in particular relates to a method and system for focusing display of two-dimensional codes.

A two-dimensional code (2_d imens i ona l ba r code ), also known as a two-dimensional bar code, is a black and white graphic that is distributed in a plane (two-dimensional direction) by a certain geometric pattern, and is all information data. A bunch of keys. In modern business activities, achievable applications are very broad, such as: product anti-counterfeiting / traceability, advertising push, website link, data download, commodity trading, positioning / navigation, electronic voucher, vehicle management, information transfer, business card exchange, wi fi Enjoy together and so on.

The current QR code scanning, such as mobile phone scanning, uses the camera + high-resolution display to display the image captured by the camera in real time on the screen, and the imaging information allows the user to adjust the shooting and framing position. This method has higher requirements on the back-end display screen, higher power consumption and cost, and is not suitable for use on a two-dimensional code scanning device of a low-resolution display, such as an OTP-type device. At present, the widely used OTP-type device is a blind shooting scheme without shooting finder. For users of non-recurring operation equipment, since the feedback of the scanning position cannot be obtained intuitively, the scanning result of the two-dimensional code is poor. The user experience is poor. Summary of the invention

In view of the deficiencies in the prior art, an object of the present invention is to provide a two-dimensional code focusing display method and system for realizing display optimization of a two-dimensional code image on a low-resolution device such as OTP. In order to achieve the above object, the technical solution adopted by the present invention is: A two-dimensional code focusing display method, comprising the following steps:

(1) acquiring a two-dimensional code image through a camera of the photographing device;

(2) extracting key information of the two-dimensional code in the two-dimensional code image; the key information includes coordinate information of a position detection pattern of the two-dimensional code;

(3) Obtain the camera resolution and display resolution of the camera device, according to the camera resolution The key information of the camera imaging coordinates in the two-dimensional code image is mapped to the key information in the display coordinate system according to the ratio of the display resolution; the display resolution is used in the display screen Displaying the resolution of the display area of the outline of the photographed object;

(4) Reconstruct the outline of the QR code image according to the key information in the display coordinate system and send it to the display. Further, in the above two-dimensional code focus display method, in the step (1), the photographing device refers to a device whose display screen resolution is lower than the resolution of the camera. Further, in the above two-dimensional code focusing display method, in step (3), according to the proportional relationship between the resolution of the camera and the resolution of the display screen, the key information in the imaging coordinates of the camera in the two-dimensional code image is Specific ways to map key information in the display coordinate system include:

1) Calculate the ratio A of the number of horizontal pixels of the camera to the number of horizontal pixels of the display screen, and the ratio B of the number of vertical pixels of the camera to the number of vertical pixels of the display screen, and use the larger of the ratios A and B as the mapping ratio. ;

2) mapping the key information in the imaging coordinates of the camera in the two-dimensional code image to the key information in the display coordinate system according to the mapping ratio. Further, in the above two-dimensional code focus display method, in step 1), the number of vertical pixels of the display screen is the number of vertical pixels of the display screen after the necessary information area is removed; The information area refers to the area on the display for displaying the hardware information of the photographing device. Further, in the above two-dimensional code focus display method, in the step (1), the two-dimensional code image is a QR code image. Further, in the above two-dimensional code focus display method, in step (4), the specific manner of reconstructing the contour of the two-dimensional code image according to the key information in the display screen coordinate system includes:

The coordinate points of the three position detection patterns of the two-dimensional code in the display coordinate system are respectively recorded as P ₂ and P ₃ , and P ₃ is located at a diagonal position of the two-dimensional code;

Calculate the coordinates of P ₂ with respect to the symmetry point P ₄ of the P ₃ line, and Pi, P ₂ , P ₃ and P ₄ are two-dimensional codes. The four vertices of the outline;

The quadrilateral contour of the two-dimensional code is constructed from the four vertices to obtain the contour of the two-dimensional code image. A two-dimensional code focusing display system, comprising:

a two-dimensional code image acquisition module, configured to acquire a two-dimensional code image by a camera of the photographing device; a two-dimensional code key information extraction module, configured to extract key information of the two-dimensional code in the two-dimensional code image; The information includes coordinate information of the position detection pattern of the two-dimensional code;

The key information mapping module is configured to acquire camera resolution and display resolution of the photographing device, and map key information of the camera image in the two-dimensional code image according to a proportional relationship between the camera resolution and the display resolution. The key information in the display coordinate system; the display resolution refers to the resolution of the display area in the display screen for displaying the outline of the photographed object;

The two-dimensional code image contour building module is configured to reconstruct the contour of the two-dimensional code image according to the key information in the display coordinate system, and send it to the display screen for display. Further, a two-dimensional code focus display system as described above, wherein the key information mapping module comprises:

The mapping ratio calculation unit is configured to calculate a key information mapping ratio, and the calculation manner is: calculating a ratio A of the number of horizontal pixels of the camera to the number of horizontal pixels of the display screen, and a ratio of the number of vertical pixels of the camera to the number of vertical pixels of the display screen B, the larger of the ratio A and the ratio B is used as a mapping ratio;

And a mapping unit, configured to map key information in the imaging coordinates of the camera in the two-dimensional code image to key information in a display coordinate system according to the mapping ratio. Still further, a two-dimensional code focus display system as described above, wherein the two-dimensional code image is a QR code image. Further, a two-dimensional code focus display system as described above, wherein the two-dimensional code image contour building module comprises:

The two-dimensional code vertex calculation unit is configured to calculate the coordinates of the fourth vertex of the two-dimensional code image, and the calculation manner is as follows: the coordinate points of the three position detection patterns of the two-dimensional code in the display coordinate system are respectively recorded as P ₂ and P ₃ , Ρ^α P _{3 are} located at the diagonal position of the two-dimensional code, and calculate the coordinates of the symmetry point Ρ ₄ of P ₂ with respect to the line connecting Ρ^α Ρ ₃ , P ₂ , P ₃ and P ₄ Four vertices of the outline of the two-dimensional code;

A contour building unit is configured to construct a quadrilateral contour of the two-dimensional code from the four vertices to obtain a contour of the two-dimensional code image. The beneficial effects of the present invention are as follows: The method and system according to the present invention, by not analyzing the feature information of the scanning target, abstracting the feature information of the scanning target, extracting the contour information and performing restoration to realize the framing position. Real-time feedback. The method and system are out of the reliance on high-resolution display devices, and are particularly useful for QR code scanning devices that use low-resolution displays, such as on cost- and power-sensitive OTP devices. DRAWINGS

1 is a structural block diagram of a two-dimensional code focus display system according to an embodiment of the present invention; FIG. 2 is a flowchart of a two-dimensional code focus display method according to an embodiment of the present invention; FIG. Schematic diagram of the code;

4 is a schematic diagram of a QR code position detection pattern in a specific embodiment;

5 is a schematic diagram of coordinates of three position detection patterns of a QR code in a specific embodiment; FIG. 6 is a schematic diagram of a QR code in a camera coordinate system in a specific embodiment;

FIG. 7 is a schematic diagram showing the display of an image in a display coordinate system in a specific embodiment. detailed description

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. 1 is a structural block diagram of a two-dimensional code focus display system in a specific embodiment of the present invention, the system includes a two-dimensional code image acquisition module 1 1 , a two-dimensional code key information extraction module 1 2, a key information mapping module 1 3 and 2D code image contour building module 14, wherein:

The two-dimensional code image acquisition module 1 1 is configured to obtain a two-dimensional code image by using a camera of the photographing device; the photographing device refers to a device whose display resolution is lower than the resolution of the camera;

The two-dimensional code key information extraction module 1 2 is configured to extract key information of the two-dimensional code in the two-dimensional code image; the key information includes coordinate information of a position detection pattern of the two-dimensional code; The key information mapping module 1 3 is configured to acquire the resolution of the camera of the photographing device and the resolution of the display screen, and according to the proportional relationship between the resolution of the camera and the resolution of the display screen, the image of the two-dimensional code image is imaged under the imaging coordinates of the camera. The key information is mapped to key information in the display coordinate system; the display resolution refers to the resolution of the display area for displaying the outline of the photographed object in the display screen; the module includes:

And a mapping unit, configured to map key information in the imaging coordinates of the camera in the two-dimensional code image to key information in a display coordinate system according to the mapping ratio.

The two-dimensional code image contour building module 14 is configured to reconstruct the contour of the two-dimensional code image according to the key information in the display coordinate system and send it to the display. For the two-dimensional code image, the original pattern is square, and the image displayed on the display after shooting is not a standard square, and is a quadrangle such as a diamond or a rectangle, and the coordinate information of the position detection pattern under the calculated display resolution is obtained. , 3⁄4 can be constructed to get the outline of the quadrilateral. The two-dimensional code image in this embodiment is a QR code image. For the QR code image, the two-dimensional code image contour building module 14 includes:

The two-dimensional code vertex calculation unit is configured to calculate the coordinates of the fourth vertex of the two-dimensional code image, and the calculation manner is as follows: the coordinate points of the three position detection patterns of the two-dimensional code in the display coordinate system are respectively recorded as P ₂ and Ρ ₃ , Ρ^α P ₃ is located at the diagonal position of the two-dimensional code, and calculates the coordinates of the symmetry point Ρ ₄ of P ₂ with respect to the line connecting Ρ^α Ρ ₃ , and P ₂ , P ₃ and P ₄ are two-dimensional codes. The four vertices of the outline;

A contour building unit is configured to construct a quadrilateral contour of the two-dimensional code from the four vertices to obtain a contour of the two-dimensional code image. 2 shows a flow chart of a two-dimensional code focus display method based on the system shown in FIG. 1, the method comprising the following steps:

Step S 2 1 : obtaining a two-dimensional code image through the camera;

The two-dimensional code image is acquired by the camera of the photographing device, and the image is saved in the memory of the OTP device. The photographing device in the specific embodiment refers to the resolution of the display screen being lower than the resolution of the camera. A camera device, such as an OTP device.

When a two-dimensional code image is acquired by a photographing device having a display resolution lower than the resolution of the camera, the camera has a higher pixel of the camera, and the image obtained by the camera is a high-resolution image, but due to the lower resolution of the display screen, Sometimes it is not possible to completely restore the information captured by the camera to the display. The present invention is a solution proposed for this problem.

In the specific embodiment, the two-dimensional code scanning coded by the QR code model 2 method widely used in the present invention is taken as an example. In the specific embodiment, the two-dimensional code image is a QR code image.

Figure 3 shows a schematic diagram of the QR code. The smallest element of the QR code (black or white square) is called the "module". The QR code is composed of black and white modules, position detection patterns, time patterns, error correction levels and masks. The format information of the code number, the data area, and the error correction code are combined. The method of the present invention is mainly implemented by extracting information (shown by point P in Fig. 3) of the position detecting pattern portion in the QR code. Step S22: extract key information of the two-dimensional code in the two-dimensional code image;

The key information of the two-dimensional code in the two-dimensional code image acquired in step S21 is extracted, and the key information includes coordinate information of the position detection pattern of the two-dimensional code, for example, the key information of the QR code image shown in FIG. The coordinates of the pattern are detected for three positions. The purpose of this step is to extract the key information of the two-dimensional code in the two-dimensional code image acquired by the camera, that is, extract the coordinate information of the position detection pattern under the imaging target coordinate system of the camera.

For the QR code, the coordinate information of the three position detection patterns of the two-dimensional code in the imaging coordinates of the camera is obtained by the image processing algorithm, and the position information is abstracted into a single pixel point to save the coordinates. In practice, since the position detecting pattern includes a plurality of pixel points as a set of coordinate information, the coordinate position information of the vertex of the position detecting pattern is used as the key information in the present embodiment.

As shown in FIG. 5, the coordinate points of the three position detection patterns of the QR code in the imaging coordinates of the camera are respectively represented as Pi, P ₂ , and P ₃ , and the specific coordinates of the three points are expressed as (ΡηΧ, ΡηΥ), and η is taken. The values correspond to 1, 1, and 3. The position detection pattern of the QR code is arranged at three corners of the QR code, as shown in Fig. 4, the ratio of the black and white modules (black and white pixels) for any position of the position detection pattern Α, Β, and C The ratio is 1: 1: 3: 1 : 1, so the key information of the QR code can be extracted from any direction, and the work efficiency is greatly improved, and high-speed reading can be supported. Step S23: mapping key information in the imaging coordinates of the camera in the two-dimensional code image to key information in the coordinate system of the display screen according to the proportional relationship between the resolution of the camera and the resolution of the display screen;

Obtaining the resolution of the camera of the photographing device and the resolution of the display screen, and mapping the key information of the camera imaging coordinates in the two-dimensional code image to the display coordinate system according to the proportional relationship between the resolution of the camera and the resolution of the display screen Key information under. The resolution of the display screen in the embodiment refers to the resolution of the display area for displaying the outline of the photographed object in the display screen, that is, the resolution of the display screen in the embodiment is not the resolution of the actual display screen, and It is the resolution of the display area of the photographing device that can be used to display the photographed image. For example, the display screen of a photographing device is an LCD screen, the resolution of the LCD screen is 128 χ 64, and the LCD screen has 1 28 χ. The area of 16 needs to be used to display other related hardware information of the device, etc., and the area of the display screen that can be used to display the photographed image is 128 X 48 , which is the display screen resolution in this embodiment.

In the embodiment, according to the proportional relationship between the resolution of the camera and the resolution of the display screen, the specific manner of mapping the key information of the two-dimensional code image into the key information in the display coordinate system includes:

1) Calculate the ratio of the number of horizontal pixels of the camera to the number of horizontal pixels of the display screen, and the ratio of the number of vertical pixels of the camera to the number of vertical pixels of the display screen, and use the larger ratio of ratio Α and ratio B as the mapping ratio. ;

2) Mapping the key information in the imaging coordinates of the camera in the two-dimensional code image according to the mapping ratio as the key information in the display coordinate system.

Wherein, in step 1), the number of vertical pixels of the display screen is the number of vertical pixels of the display screen after the necessary information area is removed; the display necessary information area refers to the hardware for displaying the photographing device on the display screen. The area of information.

In this embodiment, the coordinate information of the key information in the camera photographing imaging coordinates is recorded as (P _n X, PnY ), and the coordinate information in the mapped display coordinate system is recorded as (PnXi, ΡηΥι )»

For a camera with a resolution of 30W pixels (640 x 480), to effectively identify the coded information of the QR code, the QR code must be completely and clearly within its field of view, as shown in Figure 6. For low display devices, the number of pixels cannot satisfy the complete display of the image information saved by the camera. Therefore, the coordinates in the high coordinate system need to be mapped to the low coordinate system to meet the needs of the display device.

The display screen in this embodiment takes an LCD screen of 128×64 resolution as an example, and removes a region of 1 28×16 (such as the power display area in FIG. 7) that displays necessary information, and the remaining area pixels for mapping are 128*48. The area that matches the 640x480 image scale is: 64x48. So according to the ratio of 1 0 : 1 The key information of the two-dimensional code image under the camera resolution is mapped to the key information in the display coordinate system, that is, the coordinates (PnX, PnY) of each position information in the image saved by the camera are mapped to the coordinates of the projection field of the display field of view. (PnX , ΡηΥι ), as shown in Figure 7. Step S24: reconstructing the contour image of the two-dimensional code image according to the key information of the mapped two-dimensional code; reconstructing the contour of the two-dimensional code image according to the key information in the display coordinate system obtained in step S23, and transmitting the contour to the display The on-screen display, that is, the contour information of the position detection pattern under the resolution of the display screen can be constructed to obtain the outline of the quadrilateral.

For the QR code image, the contour of the QR code image is reconstructed based on the key information in the display coordinate system and sent to the display on the display in the following way:

The coordinate points of the three position detection patterns in the display coordinate system are respectively recorded as P ₂ and P ₃ , and Ρ ₃ is located at the diagonal position of the two-dimensional code;

Calculate the coordinates of 对称₂ with respect to the symmetry point 连₄ of the Ρ ₃ line, Pi, P ₂ , P ₃ and P ₄ are the four vertices of the two-dimensional code,

A quadrilateral contour of the two-dimensional code is constructed from the four vertices and pattern information of the two-dimensional code is generated to obtain a two-dimensional code image.

The original pattern of the QR code is square. Due to the shooting angle problem, the pattern of the image and the camera area may not be a standard square, but a diamond, a rectangle or the like. Therefore, this situation should be considered in the reconstruction of the contour. The quadrilateral is used to draw the contour. The principle of drawing the contour is as follows: Know the coordinate point information of P l, P2, P 3, and find the P2 point relative to Pl, P 3 The coordinates of the symmetry point P4 of the line, P l, P2, P 3, and P4 are the four vertices of the quadrilateral, and the contour of the quadrilateral is drawn to the display device for display.

Through the steps S21-S 24, the contour of the two-dimensional code image in the display coordinate system can be obtained, and when the photographing device scans the two-dimensional code image according to the contour, the two-dimensional code image can be visually displayed on the display screen. The contour greatly improves the recognizability of the QR code displayed on the display. It should be noted that the two-dimensional code image in the present invention includes but is not limited to the QR code image, and is applicable to other two-dimensional code images, and only needs to extract the coordinate information of the position detection pattern in the two-dimensional code image obtained by the camera, and then According to the proportional relationship between the resolution of the camera and the resolution of the display, the coordinate information under the camera coordinate system is mapped to the coordinate information under the field of view of the display screen, and The coordinate information constructs the contour of the two-dimensional code image in the display coordinate system, and uses the contour as a reference standard for capturing the two-dimensional code image, so that the image captured by the camera can be clearly displayed in the display screen.

The method and system of the present invention are equally applicable to focus display of an image having a specific feature (key information) by extracting coordinate information of a specific feature of an image under camera imaging coordinates and mapping it to a display coordinate system. With coordinate information, you can reconstruct the outline of the image in the display coordinate system.

The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

Rights request

A method for displaying a two-dimensional code focus, comprising the steps of:

(3) obtaining the camera resolution and the display resolution of the camera device, and mapping the key information of the camera imaging coordinates in the two-dimensional code image to the display screen coordinates according to the proportional relationship between the camera resolution and the display resolution. The key information of the system; the resolution of the display screen refers to the resolution of the display area for displaying the outline of the photographed object in the display screen;

(4) Reconstruct the outline of the QR code image according to the key information in the display coordinate system and send it to the display.

The method for displaying a two-dimensional code focus according to claim 1, wherein in the step (1), the photographing device refers to a device whose display screen resolution is lower than the resolution of the camera.

The method for displaying a two-dimensional code focus according to claim 1 or 2, wherein in step (3), the two-dimensional code is used according to a proportional relationship between a resolution of the camera and a resolution of the display screen. The specific ways in which the key information in the imaging coordinates of the camera is mapped to the key information in the display coordinate system include:

2) mapping the key information in the imaging coordinates of the camera in the two-dimensional code image to the key information in the display coordinate system according to the mapping ratio.

4. The method according to claim 3, wherein in step 1), the number of vertical pixels of the display screen is a vertical pixel of the display screen after the necessary information area is removed. The display necessary information area refers to an area on the display screen for displaying hardware information of the photographing device.

The method of displaying a two-dimensional code focus according to claim 4, wherein in the step (1), the two-dimensional code image is a QR code image.

The method for displaying a two-dimensional code focus according to claim 5, wherein in the step (4), the specific manner of reconstructing the contour of the two-dimensional code image according to the key information in the display coordinate system comprises: displaying The coordinate points of the three position detection patterns of the two-dimensional code in the screen coordinate system are respectively recorded as P ₂ and P ₃ , and P ₃ is located at the diagonal position of the two-dimensional code;

Calculating the coordinates of P ₂ with respect to the symmetry point P ₄ of the P ₃ line, Pi, P ₂ , P ₃ and P ₄ are the four vertices of the two-dimensional code profile;

The quadrilateral contour of the two-dimensional code is constructed from the four vertices to obtain the contour of the two-dimensional code image.

7. A two-dimensional code focusing display system, comprising:

The two-dimensional code image contour building module is configured to reconstruct the contour of the two-dimensional code image according to the key information in the display coordinate system, and send it to the display screen for display.

8. The two-dimensional code focusing display system according to claim 7, wherein the key information mapping module comprises:

a mapping unit, configured to image the camera in the two-dimensional code image according to the mapping ratio The key information in the coordinates is mapped to the key information in the display coordinate system.

9. A two-dimensional code focus display system according to claim 7 or 8, wherein the two-dimensional code image is a QR code image.

A two-dimensional code focus display system according to claim 9, wherein the two-dimensional code image contour construction module comprises:

A contour building unit is configured to construct a quadrilateral contour of the two-dimensional code from the four vertices to obtain a contour of the two-dimensional code image.