CN111079738B - Image processing method, system and terminal equipment - Google Patents

Abstract

The application is applicable to the technical field of image processing, and provides an image processing method, an image processing system and terminal equipment, wherein the method comprises the following steps: obtaining an image to be processed by scanning an original image or photographing the original image; acquiring the outline of an image to be processed so as to cut the outline to obtain a cut image; if the ground color exists in the image to be processed, extracting an RGB color space and a YCbCr color space of the cut image, and converting the cut image in the RGB color space and the YCbCr color space twice to obtain the image with the ground color removed. The method can remarkably remove the background color of the image, perform inclination calibration and clipping, and improve the image quality.

Description

An image processing method, system and terminal equipment

Technical field

The present invention relates to the field of image processing, and in particular, to an image processing method, system, terminal equipment and computer-readable storage medium.

Background technique

At this stage, it has become more and more common to use devices such as scanners, mobile phones, or cameras to scan or take photos of documents and materials to complete electronic data or transmit information. However, due to reasons such as equipment, lighting, and the document itself, scanned or photographed document images often have background colors, which affects the print quality on the one hand and subsequent OCR recognition on the other.

In addition, document images often have problems such as black edges and areas that users are not interested in, as well as problems such as tilt, which affects the user experience.

Therefore, it is necessary to propose a new technical solution to solve the above technical problems.

Contents of the invention

In view of this, embodiments of the present invention provide an image processing method, system and terminal device to solve the problem in the prior art that ideal images cannot be obtained when images are obtained by scanning or photographing.

A first aspect of the embodiment of the present invention provides an image processing method. The image processing method includes:

Obtain the image to be processed by scanning the original image or taking a photo of the original image;

Obtain the outline of the image to be processed to crop it to obtain a cropped image;

Detect whether there is a background color in the cropped image, where the background color refers to the part not included in the original image;

If it exists, extract the RGB color space and YCbCr color space of the cropped image, convert the cropped image twice in the RGB color space and YCbCr color space, and obtain the image with the background color removed.

Optionally, obtaining the outline of the image to be processed to crop it includes:

Obtain the outline of the original image corresponding to the image to be processed;

Obtain the edge lines corresponding to the contour and the intersection points between the edge lines through Hough transformation;

Mapping transformation is performed according to the edge line and the intersection point to perform tilt correction and cropping of the image to be processed.

Optionally, obtaining the outline of the original image corresponding to the image to be processed includes:

If the image to be processed is a color image, grayscale the image to be processed;

The grayscale image to be processed is binarized by the Otsu method, and morphological operations are performed to obtain the outline of the image to be processed.

Optionally, obtaining the edge lines corresponding to the contour and the intersection points between the edge lines through Hough transformation includes:

Detect the edge lines of the image to be processed through Hough transform;

Select the straight part of the edge line according to the set preset conditions;

The intersection point between the straight lines is determined based on the selected straight lines.

Optionally, converting the cropped image twice in RGB color space and YCbCr color space includes:

Convert the cropped image from RGB color space to YCbCr color space and extract each component;

Scale and filter the Y component to obtain the transformation component G, convert the Y component and the transformation component G into a floating point matrix, divide the two to obtain M=Y/G, and convert them back to an integer matrix;

Combine Y, Cb, and Cr and perform Gamma transformation to convert the image to be processed from YCbCr color space back to RGB color space.

Optionally, after converting the image to be processed from the YCbCr color space back to the RGB color space, it also includes:

Correct and fill the image converted to RGB color space to remove redundant areas.

A second aspect of the embodiment of the present invention provides an image processing system. The image processing system includes:

An image acquisition unit, used to acquire the image to be processed by scanning the original image or taking a photo of the original image;

A cropping unit, used to obtain the outline of the image to be processed to crop it to obtain a cropped image;

A detection unit that detects whether there is a background color in the cropped image, where the background color refers to the part not included in the original image;

The background color removal unit is used to extract the RGB color space and YCbCr color space of the cropped image, and convert the cropped image twice in the RGB color space and YCbCr color space to obtain an image with the background color removed.

Optionally, the cutting unit is specifically used for:

Obtain the outline of the original image corresponding to the image to be processed;

Obtain the edge lines corresponding to the contour and the intersection points between the edge lines through Hough transformation;

Mapping transformation is performed according to the edge line and the intersection point to perform tilt correction and cropping of the image to be processed.

A third aspect of the embodiment of the present invention provides a terminal device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the first aspect is implemented. and methods.

A fourth aspect of the embodiments of the present invention provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the method mentioned in the first aspect is implemented.

Compared with the prior art, the beneficial effects of the embodiments of the present invention are: in this application, after acquiring the image to be processed, the image is corrected and cropped, and then the background color is removed to obtain the ideal image. Through the above method, the image background can be significantly removed and tilt calibration and cropping can be performed to improve image quality.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings in the following description are only illustrative of the present invention. For some embodiments, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is an implementation flow chart of an image processing method provided by an embodiment of the present invention;

Figure 2 is a schematic diagram of an image to be processed provided by an embodiment of the present invention;

Figure 3 is an image to be processed after correction and cropping provided by the embodiment of the present invention;

Figure 4 is an image after background color provided by an embodiment of the present invention;

Figure 5 is a schematic structural diagram of an image processing system according to an embodiment of the present invention;

Figure 6 is a schematic structural diagram of a terminal device provided by an embodiment of the present invention.

Detailed ways

In the following description, specific details such as specific system structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the present invention in unnecessary detail.

It will be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and/or components but does not exclude one or more other features , the presence or addition of a whole, a step, an operation, an element, a component, and/or a collection thereof.

In order to illustrate the technical solution of the present invention, specific examples will be described below.

Example 1:

Figure 1 is a schematic flowchart of an image processing method provided by Embodiment 1 of the present invention. The method may include the following steps:

S11: Obtain the image to be processed by scanning the original image or taking a photo of the original image.

S12: Obtain the outline of the image to be processed and crop it to obtain a cropped image.

Specifically: obtain the outline of the original image contained in the image to be processed, obtain the area of interest and intersection coordinates through Hough transformation, correct and crop through mapping transformation.

Furthermore, the image to be processed is subjected to adaptive binarization and morphological processing to obtain the maximum contour. Hough transform is performed on the image to be processed to obtain four edge straight lines; four intersection coordinates are determined based on the edge straight lines, and mapping transformation is used to perform tilt correction and cropping of the image.

S13: Detect whether there is a background color in the cropped image, where the background color refers to the part not included in the original image.

S14: When there is a background color, extract the RGB color space and YCbCr color space of the cropped image, and convert the cropped image twice in the RGB color space and YCbCr color space to obtain an image with the background color removed.

Specifically, the original image is converted from the first color space to the second color space; the original image is subjected to background color removal processing in the second color space; and the image is converted from the second color space back to the first color space. Color space; fill the image and remove uninteresting areas such as black edges. The first color space is an RGB color space and the second color space is a YCbCr color space.

Furthermore, the above-mentioned process of removing the background color of the original image in the second color space includes: performing image scaling on the image M in the second color space, performing Gaussian filtering on the Y component to obtain G; restoring the G image, and removing The image obtained after background coloring is M=Y/G; the second color space is converted to the first color space; the contrast is adjusted to convert the image between different color spaces.

Compared with the prior art, the beneficial effects of the embodiments of the present invention are: in this application, after acquiring the image to be processed, the image is corrected and cropped, and then the background color is removed to obtain the ideal image. Through the above method, the image background can be significantly removed and tilt calibration and cropping can be performed to improve image quality.

Example 2:

The above process will be explained step by step with reference to specific embodiments:

Referring to Figures 2-4, a document image rapid correction method of the present invention includes the following steps:

Step 101, obtain the image to be processed, as shown in Figure 2;

Step 102: Perform oblique cropping on the input image to be processed. Figure 3 shows the cropped image to be processed;

Specifically, it includes the following steps:

Step 1021, when the image to be processed is a color image, grayscale it;

Step 1022: Use the Otsu method to binarize the grayscale image and perform morphological operations;

Step 1023, obtain the outer contour of the image to be processed;

Step 1024, use Hough transform to detect edge straight lines, and set threshold conditions to remove inconsistent straight lines;

Step 1025: Determine the coordinates of four intersection points based on the edge straight lines, and use mapping transformation to perform tilt correction and crop the image.

Step 103, perform background color removal processing on the image obtained in step 102;

Specifically, it includes the following steps:

Step 1031, convert the image from RGB color space to YCbCr color space;

Step 1032, separate the color space and scale the Y component to improve speed;

Step 1033: Perform Gaussian filtering on the scaled Y. The kernel size is the smaller of the width of Y and the height of Y. After filtering, G is obtained and restored to its original size;

Step 1034, Y and G are converted into floating-point matrices, divided by the two to obtain M=Y/G, and converted back to integer matrices;

Step 1035: The Y, Cb, and Cr of the image are combined and Gamma transformed;

Step 1036, the image is converted from YCbCr color space back to RGB color space;

Step 1037, image color correction;

Step 1037: Fill the image and remove uninteresting black edges and other areas to obtain the ideal picture (Figure 4 shows the image after background color removal).

Embodiment 3

FIG. 5 is a schematic structural diagram of an image processing system provided in Embodiment 3 of the present invention. For convenience of explanation, only parts related to the embodiment of the present invention are shown.

The image processing system may be a software unit, a hardware unit, or a combination of software and hardware built into the terminal device.

The image processing system includes:

The image acquisition unit 51 is used to acquire the image to be processed by scanning the original image or taking a photo of the original image;

The cropping unit 52 is used to obtain the outline of the image to be processed to crop it to obtain a cropped image;

The detection unit 53 detects whether there is a background color in the cropped image, where the background color refers to the part not included in the original image;

The background color removal unit 54 is used to extract the RGB color space and YCbCr color space of the cropped image, and convert the cropped image twice in the RGB color space and YCbCr color space to obtain an image with the background color removed.

Optionally, the cutting unit 52 is specifically used for:

Obtain the outline of the original image corresponding to the image to be processed;

Obtain the edge lines corresponding to the contour and the intersection points between the edge lines through Hough transformation;

Mapping transformation is performed according to the edge line and the intersection point to perform tilt correction and cropping of the image to be processed.

For the specific working process of the above image processing system, please refer to the implementation process of the above image processing method, which will not be described again here.

Embodiment 4

Figure 6 is a schematic structural diagram of a terminal device provided in Embodiment 4 of the present invention. As shown in FIG. 6 , the terminal device 6 of this embodiment includes: a processor 60 , a memory 61 , and a computer program 62 stored in the memory 61 and executable on the processor 60 . When the processor 60 executes the computer program 62 , the steps in the first method embodiment are implemented, such as steps S11 to S14 shown in FIG. 1 . When the processor 60 executes the computer program 62, it implements the functions of each module/unit in each of the above device embodiments, such as the functions of units 51 to 54 shown in Figure 5 .

As mentioned above, the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the foregoing. The technical solutions described in each embodiment may be modified, or some of the technical features may be equivalently replaced; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims (9)

1. An image processing method, characterized in that the image processing method includes: Obtain the image to be processed by scanning the original image or taking a photo of the original image; Obtain the outline of the image to be processed to crop it to obtain a cropped image; Detect whether there is a background color in the cropped image, where the background color refers to the part not included in the original image; If it exists, extract the RGB color space and YCbCr color space of the cropped image, convert the cropped image twice in the RGB color space and YCbCr color space, and obtain the image after removing the background color; The two conversions of the cropped image into RGB color space and YCbCr color space include: Convert the cropped image from RGB color space to YCbCr color space and extract each component; Scale and filter the Y component to obtain the transformation component G, convert the Y component and the transformation component G into a floating point matrix, divide the two to obtain M=Y/G, and convert them back to an integer matrix; Combine Y, Cb, and Cr and perform Gamma transformation to convert the image to be processed from YCbCr color space back to RGB color space; Specific background color removal in YCbCr color space includes: Perform image scaling on the image M in the YCbCr color space, perform Gaussian filtering on the Y component, and use the smaller of the width of Y and the height of Y as the kernel size to obtain the transformation component G; convert the Y component and the transformation component G into floating point numbers. Matrix, divide the two to get the image after removing the background color, M=Y/G; and convert it back to the shaping matrix. 2. The image processing method according to claim 1, characterized in that said obtaining the outline of the image to be processed to crop it includes: Obtain the outline of the original image corresponding to the image to be processed; Obtain the edge lines corresponding to the contour and the intersection points between the edge lines through Hough transformation; Mapping transformation is performed according to the edge line and the intersection point to perform tilt correction and cropping of the image to be processed. 3. The image processing method according to claim 2, wherein said obtaining the outline of the original image corresponding to the image to be processed includes: If the image to be processed is a color image, grayscale the image to be processed; The grayscale image to be processed is binarized by the Otsu method, and morphological operations are performed to obtain the outline of the image to be processed. 4. The image processing method according to claim 1, wherein obtaining the edge line corresponding to the contour and the intersection between the edge lines through Hough transformation includes: Detect the edge lines of the image to be processed through Hough transform; Select the straight part of the edge line according to the set preset conditions; 5. The image processing method according to claim 1, characterized in that, after converting the image to be processed from the YCbCr color space back to the RGB color space, it further includes: Correct and fill the image after converting it back to RGB color space, and remove redundant areas. 6. An image processing system using the image processing method according to any one of claims 1 to 5, characterized in that the image processing system includes: An image acquisition unit, used to acquire the image to be processed by scanning the original image or taking a photo of the original image; A cropping unit, used to obtain the outline of the image to be processed to crop it to obtain a cropped image; A detection unit that detects whether there is a background color in the cropped image, where the background color refers to the part not included in the original image; The background color removal unit is used to extract the RGB color space and YCbCr color space of the cropped image, convert the cropped image twice in the RGB color space and the YCbCr color space, and remove the background color in the YCbCr color space to obtain the background removal Colored image. 7. The image processing system according to claim 6, characterized in that the cropping unit is specifically used to: Obtain the outline of the original image corresponding to the image to be processed; Obtain the edge lines corresponding to the contour and the intersection points between the edge lines through Hough transformation; Mapping transformation is performed according to the edge line and the intersection point to perform tilt correction and cropping of the image to be processed. 8. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that when the processor executes the computer program, it implements the claims as claimed in The steps of the method of any one of 1 to 5. 9. A computer-readable storage medium, the computer-readable storage medium stores a computer program, characterized in that, when the computer program is executed by a processor, the method of any one of claims 1 to 5 is implemented. step.