WO2019200658A1

WO2019200658A1 - Method for image smoothing processing, electronic device, and computer readable storage medium

Info

Publication number: WO2019200658A1
Application number: PCT/CN2018/088019
Authority: WO
Inventors: 朱江; 赵斌; 张裕桦; 陈宏贵
Original assignee: 深圳市华星光电技术有限公司
Priority date: 2018-04-16
Filing date: 2018-05-23
Publication date: 2019-10-24
Also published as: CN108513044B; CN108513044A

Abstract

Disclosed is a method for image smoothing processing, comprising: extracting a luminance component from an inputted image; performing, according to the extracted luminance component, flat region detection on the image to determine whether each pixel of the image is in a flat region; if the pixel is in a flat region, performing smoothing processing on the pixel; and after compositing luminance components, outputting a smoothened image. Also disclosed are an electronic device and a computer readable storage medium. The invention can suppress noise in a flat region of an image, and enables a luminance component at the flat region to have moderate gradation, thereby improving image quality.

Description

Image smoothing processing method, electronic device and computer readable storage medium

Technical field

The present invention relates to the field of image processing technologies, and in particular, to an image smoothing processing method, an electronic device, and a computer readable storage medium.

Background technique

With the development of technology and changes in market demand, flat-panel TVs are becoming more and more popular, and the resolution of TVs is getting higher and higher. The demand for high-resolution video and signals is also growing. However, there are still many video files and signal sources with low resolution. These video files and signal sources will bring noise when they are amplified to the required resolution on a flat-panel TV. In particular, watermarks and mosaics appear in flat areas of the image, which seriously affects the quality of the image.

Summary of the invention

A main object of the present invention is to provide an image smoothing processing method, an electronic device, and a computer readable storage medium, aiming at solving the problem of how to process a flat region of an image to suppress noise.

To achieve the above objective, the present invention provides an image smoothing processing method, the method comprising the steps of:

Extracting a luminance component from the input image;

Performing flat area detection on the image according to the extracted luminance component, and determining whether each pixel in the image is in a flat area;

Smoothing the pixels when the pixels are in a flat region; and

The smoothed image is output after the luminance component is combined.

Optionally, after the step of extracting a luminance component from the input image, the method further includes the steps of: performing a bit number enhancement on the luminance component, thereby performing flat region detection on the image according to the enhanced luminance component;

Before the step of combining the luminance components, the method further includes the step of: converting the new luminance value processed by each pixel in the image into a low bit by the dither display, thereby performing luminance component synthesis according to the converted luminance component data.

Optionally, in the step of performing bit number enhancement on the luminance component, converting the number of bits of the luminance component from 8 bits to 10 bits or 12 bits;

In the step of converting the new luminance value into a low bit, the number of bits of the new luminance value after each pixel processing is changed from 10 bit or 12 bits to 8 bits.

Optionally, the flat area detection comprises the steps of:

Calculating the flatness value of each target pixel;

Determining, from the target pixel, a maximum value of the flatness value of the pixel in the preset area according to a preset area size M*N;

Comparing the flatness maximum value with a preset threshold value, if the flatness maximum value is smaller than the threshold value, the target pixel needs to perform smoothing processing; otherwise, the target pixel does not need to perform smoothing processing. .

Optionally, the flatness value is a maximum value of absolute values of luminance differences of the target pixel and adjacent pixels.

In addition, in order to achieve the above object, the present invention also provides an electronic device, the electronic device comprising: a memory, a processor, and an image smoothing processing program stored on the memory and operable on the processor, The image smoothing process is implemented by the processor to implement the following steps:

Extracting a luminance component from the input image;

Smoothing the pixels when the pixels are in a flat region; and

The smoothed image is output after the luminance component is combined.

Optionally, after the step of extracting the luminance component from the input image, the method further includes the step of: performing a bit increase on the luminance component, thereby performing flat region detection on the image according to the enhanced luminance component;

Optionally, the flat area detection comprises the steps of:

Calculating the flatness value of each target pixel;

Further, in order to achieve the above object, the present invention further provides a computer readable storage medium having an image smoothing processing program stored thereon, and the image smoothing processing program is executed by a processor to implement the above The steps of the image smoothing method.

The image smoothing processing method, the electronic device and the computer readable storage medium proposed by the invention are mainly used for suppressing noise of a flat region of an image, and gradually grading a luminance component of the flat region of the image. First, the image brightness component is detected, and whether the pixel is in a flat area is detected according to the size of the preset area, and then the center point pixel of the area is smoothed, thereby improving the image quality and the display quality of the electronic device. In addition, the luminance component is converted into a high bit for calculation, and then restored to a low level by the dithering display, which improves the arithmetic precision, so that the luminance component of the output image flat region changes more gently. The probability of the target pixel being in a flat region is judged by taking the maximum value of the absolute value of the luminance difference between the target pixel and the adjacent pixel, and the calculation method is simple and convenient for hardware implementation. By setting the size of the area, the smoothing ability of the pixels in the flat area can be controlled, which is simple, flexible, and practical.

DRAWINGS

1 is a block diagram of an electronic device according to a first embodiment of the present invention;

2 is a flowchart of an image smoothing processing method according to a second embodiment of the present invention;

3 is a flowchart of an image smoothing processing method according to a third embodiment of the present invention;

4 is a schematic diagram of a target pixel and its adjacent pixels in the present invention;

Fig. 5 is a schematic view showing the maximum value of flatness in a preset area in the present invention.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Embodiment 1

Referring to FIG. 1, a first embodiment of the present invention provides an electronic device 2. The electronic device 2 has an image display and image processing function, and may be a flat panel television or the like. The electronic device 2 includes a memory 20, a processor 22, and an image smoothing program 28.

The memory 20 includes at least one type of readable storage medium for storing an operating system and various types of application software installed in the electronic device 2, such as program code of the image smoothing program 28. Further, the memory 20 can also be used to temporarily store various types of data that have been output or are to be output.

The processor 22 may be a Central Processing Unit (CPU), controller, microcontroller, microprocessor, or other data processing chip in some embodiments. The processor 22 is typically used to control the overall operation of the electronic device 2. In this embodiment, the processor 22 is configured to run program code or process data stored in the memory 20, such as running the image smoothing process 28 and the like.

When the image smoothing program 28 is executed by the processor 22, the following steps are implemented:

(1) Extracting a luminance component from the input image.

(2) The number of bits of the luminance component is increased.

(3) Performing flat area detection on the image based on the boosted luminance component, and determining whether each pixel in the image is in a flat area.

(4) When the pixel is in a flat area, the pixel is smoothed.

(5) Converting the new luminance value processed by each pixel in the image to a low level.

(6) The smoothed image is output after the luminance component is combined.

For details of the above steps, please refer to the following second embodiment and the third embodiment, and details are not described herein again.

It will be understood by those skilled in the art that the structure shown in FIG. 2 does not constitute a limitation on the electronic device 2, and the electronic device 2 may further include other necessary components (such as a screen, etc.), or combine some components, or Different parts are arranged.

Embodiment 2

Referring to FIG. 2, a second embodiment of the present invention provides an image smoothing processing method applied to the electronic device 2. In this embodiment, the order of execution of the steps in the flowchart shown in FIG. 2 may be changed according to different requirements, and some steps may be omitted. The method includes the following steps:

S100, extracting a luminance component from the input image.

Specifically, in general, each pixel in an image may include a luminance component, a chrominance component, and the like. When it is necessary to smooth the image, the input image is first acquired, and then the luminance component of the image is extracted. The color space that the image can take is YUV, HSL or HSV, and the like.

S102. Perform flat area detection on the image according to the extracted luminance component, and determine whether each pixel in the image is in a flat area. When the pixel is in a flat area, step S104 is performed. When the pixel is in a non-flat area, step S106 is directly performed.

Specifically, after the luminance component is extracted from the image, it is necessary to perform flat region detection for each pixel according to the luminance component. The pixels in the flat area are smoothed, and the pixels in the non-flat area are not processed.

In this embodiment, the flat area detection includes:

(1) Calculate the flatness value of each pixel (referred to as a target pixel). The flatness value is a maximum value among absolute values of luminance differences of the target pixel and the adjacent pixels (eight pixels around). As shown in FIG. 4, it is a schematic diagram of a target pixel and its neighboring pixels. Wherein, the pixel (j, i) is the target pixel, and the other pixels are adjacent pixels of the pixel (j, i). This step requires traversing each of the target pixels in the image to calculate a corresponding flatness value. For ease of calculation, the target pixel ends from the second row of the image to the penultimate row, ending with each row starting from the second pixel to the second to last pixel. Calculated as follows:

F1=|y(j,i)–y(j,i-1)|;

F2=|y(j,i)–y(j,i+1)|;

F3=|y(j,i)–y(j-1,i-1)|;

F4=|y(j,i)–y(j-1,i)|;

F5=|y(j,i)–y(j-1,i+1)|;

F6=|y(j,i)–y(j+1,i-1)|;

F7=|y(j,i)–y(j+1,i)|;

F8=|y(j,i)–y(j+1,i+1)|;

Fabs(j,i)=max(f1f2f3f4f5f6f7f8);

Where y represents the luminance component of the corresponding pixel, and fabs(j, i) represents the flatness value of the pixel (j, i). The smaller the flatness value, the greater the likelihood that the pixel is in a flat region.

(2) The maximum value of the flatness value of the pixels in the preset area is obtained according to the preset area size M*N centering on the target pixel. Among them, M and N are generally odd numbers, such as 3*3, 5*5, 7*7, etc., the larger the area is set, the stronger the subsequent smoothing processing capability. As shown in FIG. 5, it is a schematic diagram of finding the maximum value of the flatness in the preset area. In FIG. 5, the size of the preset area is 5*5, and the maximum value of the flatness value of 25 pixels in the area is calculated.

(3) comparing the flatness maximum value with a preset threshold value, if the flatness maximum value is smaller than the threshold value, the target pixel needs to perform smoothing processing; otherwise, the target pixel does not need to be processed. Smoothing is performed.

S104: Smooth processing the pixel.

Specifically, when the target pixel is in a flat region, the target pixel is smoothed. In this embodiment, the smoothing process adopts an averaging method, that is, the new luminance value of the target pixel is an average value of luminance values of all pixels in the preset region.

S106, after the luminance component is synthesized, the smoothed image is output.

Specifically, the luminance component synthesis is performed according to the new luminance value of each pixel in the image, and inversely transformed into the RGB data output by the corresponding color space.

In the image smoothing processing method proposed in this embodiment, the image brightness component is first detected, and whether the pixel is in a flat area is detected according to a preset size of the area, and then the center point pixel (target pixel) of the area is smoothed to The noise in the flat region of the image is suppressed, and the luminance component of the flat region of the image is gently graded, thereby improving the quality of the image and the display quality of the electronic device. In addition, by taking the maximum value of the absolute value of the luminance difference between the target pixel and the adjacent pixel to judge the possibility that the target pixel is in a flat region, the calculation method is simple and convenient for hardware implementation. By setting the size of the area, the smoothing ability of the pixels in the flat area can be controlled, which is simple, flexible, and practical.

Embodiment 3

Referring to FIG. 3, a third embodiment of the present invention provides an image smoothing processing method. In the third embodiment, the steps of the image smoothing processing method are similar to those of the second embodiment, except that the method further includes steps S202 and S208.

The method includes the following steps:

S200, extracting a luminance component from the input image.

Specifically, in general, each pixel in an image may include a luminance component, a chrominance component, and the like. When edge enhancement of an image is required, the input image is first acquired, and then the luminance component of the image is extracted. The color space that the image can take is YUV, HSL or HSV, and the like.

S202. Perform a bit increase on the brightness component.

Specifically, the number of bits of the luminance component is changed from 8 bits to 10 bits or 12 bits or higher.

S204: Perform flat area detection on the image according to the enhanced luminance component, and determine whether each pixel in the image is in a flat area. When the pixel is in a flat area, step S206 is performed. When the pixel is in a non-flat area, step S208 is directly performed.

Specifically, after the number of bits of the luminance component is increased, it is necessary to perform flat region detection for each pixel according to the luminance component. The pixels in the flat area are smoothed, and the pixels in the non-flat area are not processed.

In this embodiment, the flat area detection includes:

F1=|y(j,i)–y(j,i-1)|;

F2=|y(j,i)–y(j,i+1)|;

F3=|y(j,i)–y(j-1,i-1)|;

F4=|y(j,i)–y(j-1,i)|;

F5=|y(j,i)–y(j-1,i+1)|;

F6=|y(j,i)–y(j+1,i-1)|;

F7=|y(j,i)–y(j+1,i)|;

F8=|y(j,i)–y(j+1,i+1)|;

Fabs(j,i)=max(f1f2f3f4f5f6f7f8);

S206, performing smoothing on the pixel.

S208. Convert a new brightness value of each pixel in the image to a low level.

Specifically, for a new luminance value of each pixel in the image, it is converted from a high bit (10 bit or 12 bit) to 8 bit by dithering. For the pixels that have not been smoothed, the new luminance value is the same as the luminance component value after the digit enhancement, and no change occurs.

S210, after the luminance component is synthesized, the smoothed image is output.

Specifically, the converted luminance component data is subjected to luminance component synthesis, and inversely transformed into RGB data output by the corresponding color space.

The image smoothing processing method proposed in this embodiment firstly converts the luminance component into a high level for calculation, and then restores the luminance component from a high level to a low level through the dither display, thereby improving the operation precision and making the brightness component of the output image flat region change more. Smooth, better image processing.

Embodiment 4

The present invention further provides another embodiment, that is, a computer readable storage medium storing an image smoothing processing program, the image smoothing processing program being executable by at least one processor, The at least one processor is caused to perform the steps of the image smoothing processing method as described above.

It is to be understood that the term "comprises", "comprising", or any other variants thereof, is intended to encompass a non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes those elements. It also includes other elements that are not explicitly listed, or elements that are inherent to such a process, method, article, 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 serial numbers of the embodiments of the present invention are merely for the description, and do not represent the advantages and disadvantages of the embodiments.

Through the description of the above embodiments, those skilled in the art can clearly understand that the foregoing embodiment method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be through hardware, but in many cases, the former is better. Implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal (which may be a cell phone, a computer, a server, an air conditioner, or a network device, etc.) to perform the methods described in various embodiments of the present invention.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the specific embodiments described above, and the specific embodiments described above are merely illustrative and not restrictive, and those skilled in the art In the light of the present invention, many forms may be made without departing from the spirit and scope of the invention as claimed.

Claims

An image smoothing method, wherein the method comprises the steps of:

Extracting a luminance component from the input image;

Performing flat area detection on the image according to the extracted luminance component, and determining whether each pixel in the image is in a flat area;

Smoothing the pixels when the pixels are in a flat region; and

The smoothed image is output after the luminance component is combined.
The image smoothing processing method according to claim 1, wherein the method further comprises the step of: performing a digit enhancement on the luminance component after the step of extracting a luminance component from the input image, thereby based on the luminance component after the enhancement Performing flat area detection on the image;

Before the step of combining the luminance components, the method further includes the step of: converting the new luminance value processed by each pixel in the image into a low bit by the dither display, thereby performing luminance component synthesis according to the converted luminance component data.
The image smoothing processing method according to claim 2, wherein in the step of increasing the number of bits of the luminance component, the number of bits of the luminance component is changed from 8 bits to 10 bits or 12 bits;

In the step of converting the new luminance value into a low bit, the number of bits of the new luminance value after each pixel processing is changed from 10 bit or 12 bits to 8 bits.
The image smoothing processing method according to claim 1, wherein said flat area detection comprises the steps of:

Calculating the flatness value of each target pixel;

Determining, from the target pixel, a maximum value of the flatness value of the pixel in the preset area according to a preset area size M*N;

Comparing the flatness maximum value with a preset threshold value, if the flatness maximum value is smaller than the threshold value, the target pixel needs to perform smoothing processing; otherwise, the target pixel does not need to perform smoothing processing. .
The image smoothing processing method according to claim 2, wherein said flat area detection comprises the steps of:

Calculating the flatness value of each target pixel;

Determining, from the target pixel, a maximum value of the flatness value of the pixel in the preset area according to a preset area size M*N;

Comparing the flatness maximum value with a preset threshold value, if the flatness maximum value is smaller than the threshold value, the target pixel needs to perform smoothing processing; otherwise, the target pixel does not need to perform smoothing processing. .
The image smoothing processing method according to claim 4, wherein the flatness value is a maximum value among absolute values of luminance differences of the target pixel and adjacent pixels.
The image smoothing processing method according to claim 5, wherein the flatness value is a maximum value among absolute values of luminance differences of the target pixel and adjacent pixels.
An electronic device, comprising: a memory, a processor, and an image smoothing program stored on the memory and operable on the processor, the image smoothing program being The following steps are implemented during execution:

Extracting a luminance component from the input image;

Performing flat area detection on the image according to the extracted luminance component, and determining whether each pixel in the image is in a flat area;

Smoothing the pixels when the pixels are in a flat region; and

The smoothed image is output after the luminance component is combined.
The electronic device according to claim 8, wherein the step of extracting the luminance component from the input image further comprises the step of: increasing the number of bits of the luminance component to thereby perform the image on the image according to the enhanced luminance component Flat area detection;

Before the step of combining the luminance components, the method further includes the step of: converting the new luminance value processed by each pixel in the image into a low bit by the dither display, thereby performing luminance component synthesis according to the converted luminance component data.
The electronic device of claim 8, wherein the flat region detection comprises the steps of:

Calculating the flatness value of each target pixel;

Determining, from the target pixel, a maximum value of the flatness value of the pixel in the preset area according to a preset area size M*N;

Comparing the flatness maximum value with a preset threshold value, if the flatness maximum value is smaller than the threshold value, the target pixel needs to perform smoothing processing; otherwise, the target pixel does not need to perform smoothing processing. .
The electronic device of claim 9, wherein the flat area detection comprises the steps of:

Calculating the flatness value of each target pixel;

Determining, from the target pixel, a maximum value of the flatness value of the pixel in the preset area according to a preset area size M*N;

Comparing the flatness maximum value with a preset threshold value, if the flatness maximum value is smaller than the threshold value, the target pixel needs to perform smoothing processing; otherwise, the target pixel does not need to perform smoothing processing. .
The electronic device according to claim 10, wherein the flatness value is a maximum value among absolute values of luminance differences of the target pixel and adjacent pixels.
The electronic device according to claim 11, wherein the flatness value is a maximum value among absolute values of luminance differences of the target pixel and adjacent pixels.
A computer readable storage medium, wherein the computer readable storage medium stores an image smoothing processing program, and the image smoothing processing program is executed by a processor to implement the steps of the image smoothing processing method according to claim 1. .