KR101022311B1 - Embedded system using approximate lossless image coding method and image processing method thereof - Google Patents

Abstract

An embedded system using an approximate lossless compression technique and an image processing method thereof are disclosed. An embedded system according to the present invention includes a transparency bitmap generator for generating a transparency bitmap using color information of an input color image; A minimum bounding box setting unit configured to set a minimum bounding box area including a non-transparent area based on the transparency bitmap generated by the transparency bitmap generator; A compression unit configured to compress the transparency bitmap generated by the transparency bitmap generation unit using a lossless compression method and to perform JPEG loss compression on the minimum bounding box area set by the minimum bounding box setting unit; And a compressed stream generating unit for generating a compressed stream by combining the lossless compressed stream and the lost compressed stream compressed by the compression unit.

Embedded systems, color information, transparency bitmaps, lossless, lossy compression

Description

Embedded system using approximate lossless image coding method and image processing method

The present invention relates to an embedded system and an image processing method thereof, and more particularly, to an embedded system and an image processing method for encoding an image to be used as a user interface using an approximate lossless compression technique.

Most embedded systems have hardware specifications optimized for the processor's computing power, memory usage, and display device size to meet the intended use. However, in order to provide convenient use of the embedded equipment, most of the user interface adopts a Graphical User Interface (GUI) using image or graphic data, thereby interacting with the user, thereby providing the user with the embedded system. It offers dynamic effects and visual convenience. However, when storing graphics or video resources in an embedded system, a very large storage device is required. Also, in order to execute the video and graphic resources stored in the storage device as the user interface is activated and interact with the user, fast image processing is required. A lot of buffer memory is needed for this.

In order to provide a user interface using an image in a conventional mobile terminal or a portable embedded system, a run length based image compression technique and an image compression technique using a directory concept are used. The image used in the user interface is different from the characteristics of real-life images, such as photographs, mainly because of the large number of gradients or images generated using graphic tools. In particular, images used as a user interface may be assigned by using a specific color as a transparent color, so that a loss that is noticeable to the user when lossy compression occurs.

Because of the above problems, video resources used as a user interface utilize a lossless compressed video technique to minimize the storage space of a mobile terminal by reducing the amount of resources.

A typical compression technique is a Run Length-based compression technique that is effective for simple but artificially synthesized images. When the same color is expressed as a pair of run and run lengths, the amount of data can be reduced rather than representing each pixel of the image. have.

Another method is that most terminals use 16-bit color, and when the display is displayed, the trimmed portion of the 24-bit color is cut in advance, and then the existing run length technique is applied or LZW, LZO, ZIP, PNG, Using the JPEG-LS application technique, the image compression techniques used for the user interface of the portable terminal apply a relatively simple method in consideration of the performance of the portable terminal. However, such compression techniques have a disadvantage in that the compression efficiency is not high.

In addition, the same techniques that take existing compression techniques and optimize them in terms of speed have been applied to mobile terminals. The preprocessing process to increase the compression efficiency is mainly a method of increasing the compression efficiency by removing a high frequency region or removing noise from a live image. Have been used.

In addition, the discontinuity feature of the image is used to emphasize the user interface image. The preprocessing process of removing the high frequency region causes a problem of removing the main characteristics of the image to be used in the user interface image.

The present invention was devised to solve the above problems, reflecting characteristics such as high compression efficiency and transparent color designation, which are widely used in a graphic user interface, to be compressed and lossless in the user interface configuration even if loss occurs. It is an object of the present invention to provide an embedded system and an image processing method capable of reducing the data amount of image data used as a graphical user interface by applying an approximate lossless image compression technique so as not to cause a problem.

In addition, the present invention was devised to solve the lossless requirements of the image used in the user interface, the graphic and image data used as the user interface and the information and loss to be processed losslessly by receiving the value of the transparent designated color The purpose of the present invention is to provide an embedded system and an image processing method for improving the overall compression efficiency and satisfying the requirements of the user interface by applying a lossless compression technique and a lossy compression technique by dividing it into areas that do not affect the user interface. do.

Embedded system according to the present invention for achieving the above object, the transparency bitmap generation unit for generating a transparency bitmap using the color information of the input color image; A minimum bounding box setting unit configured to set a minimum bounding box area including a non-transparent area based on the transparency bitmap generated by the transparency bitmap generator; A compression unit configured to compress the transparency bitmap generated by the transparency bitmap generation unit using a lossless compression method and to perform JPEG loss compression on the minimum bounding box area set by the minimum bounding box setting unit; And a compressed stream generating unit for generating a compressed stream by combining the lossless compressed stream and the lost compressed stream compressed by the compression unit.

Here, the embedded system may further include a storage unit for storing the image resource compressed by the compression unit.

In addition, the compression unit preferably compresses by allocating a pixel value of a non-transparent region to a transparent region within the minimum bounding box region.

In addition, the compression unit preferably uses blocking and encoding of the transparency bitmap to increase compression efficiency of the transparency bitmap.

In the embedded system for achieving the above object, an embedded system for performing image processing on the input color image, a lossless compression method and a lossy compression method based on a transparency bitmap according to the color information of the input color image It may be implemented by using together to compress an image and combine the compressed lossless compressed stream and the lost compressed stream.

On the other hand, the embedded system is an image processing method of an embedded system for improving the image compression efficiency, comprising the steps of: generating a transparency bitmap using the color information of the input color image; Setting a minimum bounding box area including a non-transparent area based on the generated transparency bitmap; Compressing the generated transparency bitmap using a lossless compression method and lossy compressing the set minimum bounding box area; And generating a compressed stream by combining the lossless compressed stream and the lost compressed stream compressed by the compressing step.

The image processing method of the embedded system may further include storing the video resource compressed stream generated by the compressed stream generating step.

The image processing method of the embedded system may further include assigning a pixel value of a non-transparent region to a transparent region within the minimum bounding box region, in which case the JPEG loss compression is performed on the minimum bound box region. It is preferable.

The image processing method of the embedded system may further include blocking and encoding the transparency bitmap in order to increase the compression efficiency of the transparency bitmap, in which case the loss of the blocked and encoded transparency bitmap is lost. It is preferable to compress.

The present invention can be applied to an embedded system that outputs an image by installing a liquid crystal display (LCD) such as a portable terminal device, a portable game machine, and a portable media player, and implements a graphic user interface in a terminal having limited image resource memory. In order to reduce the amount of resources used for the image, the image is compressed using an approximate lossless compression method to store a large amount of resource image data, thereby using a more dynamic image and graphical user interface (GUI) representation. Make it possible.

Therefore, more image data can be stored in an embedded system having the same storage device, thereby reducing the cost of the storage device or storing a lot of resources for constructing a more diverse user interface. It can be widely used in other applications using conventional lossless image compression.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. However, the embodiments of the present invention described below are provided to enable those skilled in the art to more easily understand the present invention, and the scope of the present invention is not limited to the described embodiments.

1 is a view schematically showing an embedded system according to the present invention. Referring to the drawings, the embedded system 100 according to the present invention includes a transparency bitmap generator 10, a minimum bounding box setting unit 20, a compression unit 30, a compressed stream generator 40, and a storage unit. 50 is provided.

The transparency bitmap generator 10 receives the image used as the user interface and the color information to be used as the transparent color and generates a transparency bitmap using the transparent color information. Here, the transparency color is a specific color of the image to be used in the user interface, and the part set to this color is outputted as it is when the background color is reproduced on the screen, and other colors are output to the color set to the image. Therefore, a color designated as a transparent color must be free of losses. The loss of the transparency color means another color. When the loss occurs, the damaged color value is output instead of the background color at the location where the loss occurs. In order to set an area designated as a transparent color for compressing the transparent color area, the transparency bitmap generation unit 10 displays a portion to be output as a background color when outputting to the screen as a bitmap through a transparency bitmap using a transparency color value. do. That is, the pixel area indicated by the bit '1' outputs the background color, and the area set as the bit '0' outputs the pixel value of the image as the non-transparent area. The transparent bitmap compares a color value designated as a transparent color with each pixel value of an input image and sets the bit value to '1' at pixel positions having the same color and '0' at other colors. The size of the transparency bitmap is the same as the size of the input image.

The minimum bounding box setting unit 20 sets the minimum bounding box area including the non-transparent area according to the transparency bitmap based on the transparency bitmap generated in the transparency bitmap generator 10.

The compression unit 30 compresses the transparency bitmap generated by the transparency bitmap generation unit 10 using a lossless compression method and JPEG loss compression the minimum bounding box area set by the minimum bounding box setting unit. Here, the compression unit 30 preferably assigns and compresses the pixel value of the non-transparent region to the transparent region in the minimum bounding box region. In addition, the compression unit 30 preferably blocks and codes the transparency bitmap in order to increase the compression efficiency of the transparency bitmap. That is, the compression unit 30 encodes the bitmap by dividing the transparency bitmap into blocks in order to improve compression efficiency, and then compresses each code through a lossless compression technique. The size of the block divided into blocks may vary depending on the application, but the block size is set to have the same bit value as much as possible. Blocking and encoding is a method for increasing lossless compression efficiency by causing the same code values to be generated in succession by using locality characteristics of an image, in which adjacent pixels, which are general characteristics of an image, are likely to have similar values. The lossless compression scheme of the transparency bitmap may utilize various conventional lossless data compression techniques.

The minimum bounding box setting unit 20 including the non-transparent region using the transparency bitmap and the compression unit 30 for compressing the non-transparent region are to increase the compression efficiency of the image resource, A minimum bounding box including all '0' values represented by the transparent area is set, and only the minimum bounding box area in the input video resource is compressed with lossy compression. Some of the edges in the minimum bounding box area may include pixels set to a transparent color, and color values of the corresponding pixels assign values of non-transparent pixels in the boundary area to increase efficiency of lossy compression. An area assigned a boundary value to the transparent area in the area is compressed through JPEG loss compression. JPEG compression is lossy compression, so you can set the image quality so that the image quality is not noticeable by the user.

The compressed stream generator 40 combines the lossless compressed stream of the transparent bitmap compressed by the compressor 30 and the lossy compressed stream of the minimum bounding box region including the opaque region to be used as a user interface. Create

The storage unit 50 stores the video resource compressed stream for the user interface compressed by the compression unit 30. The video resource compression stream stored in the storage unit 50 is decoded when the user interface is output when the embedded system 100 is activated and used as the video resource.

2 is a flowchart illustrating an image processing method by the embedded system of FIG. 1. With reference to the drawings will be described in detail the operation and function of the embedded system according to the present invention.

2 illustrates a process of performing approximate lossless compression on an image used as a user interface of the embedded system 100 according to the present invention. In general, an image used for a user interface is a color image, and each component of the color is represented by 8 bits.

The bitmap generator 10 generates a transparency bitmap using a color image for the user interface input by the input step S101 and color information to be used as a transparent color in the image (S103). Here, the color information includes information on brightness, saturation, and luminance.

The minimum bounding box setting unit 20 finds a non-transparent region using the transparency bitmap generated by the bitmap generator 10 and sets a minimum bounding box including the non-transparent region (S105).

The compression unit 30 comprises a step of blocking and encoding a transparency bitmap in order to compress the transparency bitmap by a lossless compression technique (S107) and a step of compressing the transparency bitmap code by a lossless compression technique (S109). Bitmap lossless compression step, and lossless compression of the non-transparent region to obtain a compression efficiency. Here, the lossy compression may include assigning a boundary value of the non-transparent region to the transparent region in the minimum bounding box region including the non-transparent region (S111) and lossy compressing the minimum bounding region of the previous step (S113). It is provided. The lossless compressed stream and the lossy compressed stream compressed by the compression unit 30 are combined by the compression stream generation unit 40 to be generated as a compressed stream and stored in the storage unit 50 (S115 and S117).

In detail, a process of generating a transparency bitmap using the transparency color will be described with reference to FIGS. 3 and 4.

3 is an input image, and the part numbers 4 and 6 are object areas used as non-transparent areas in the input image 2, and the part number 8 is an area designated by a transparent color. In order to compress the input image 2, a transparency bitmap is obtained as shown in FIG. 4. That is, while scanning an input image, bit 1 is allocated to a pixel position having a value equal to a color value and a transparent color input value of the input image, and a bit 0 value is assigned to a pixel position having a different color value. 4 is a transparency color bitmap made of the input image of FIG. 3 as an example.

The transparency bitmap of FIG. 4 is compressed using a conventional lossless compression technique. Blocking and coding are performed to increase the compression efficiency. For example, when the block size is 8x8, the transparency bitmap is divided into blocks without overlapping as shown in reference numeral 12 and 8-bit values are assigned in scanning order in each block. For example, the first block of part number 12 generates eight code values, with the first line of the block 0xff, the second line 0xf3, the third line 0xe0, the fourth line 0xe0, the fifth line 0xe0, the sixth line 0xf0, The seventh line has a value of 0xf0 and the eighth line has a value of 0xf1. Of course, the size of the block can be different, but it is preferable to determine the multiple of 8 in consideration of the compression efficiency and the computer representation method. In FIG. 3, a block coded value may be compressed using a conventional lossless data compression scheme, and the compression scheme is not limited in the present invention.

FIG. 5 shows an example of setting a minimum bounding box including a non-transparent area in an input image input by the input step S101 of FIG. 2. In general, image compression compresses the entire input image. However, in the present invention, the transparent bitmap is lossless, allowing loss that is inconspicuous even if a loss occurs, thereby increasing compression efficiency through approximate lossless compression. In FIG. 5, a transparent area that is not a non-transparent object within a minimum bounding box area such as a part number 9 including non-transparent objects of 4 and 6 includes a pixel value bounded by the non-transparent object in order to increase loss compression efficiency. Copy as is to set the color value. Afterwards, the minimum bounding box region of the absent Bunno 9 is compressed using a JPEG compression algorithm, which is a lossy compression technique.

A lossy compression of the transparent bitmap and a lossy compression stream of the minimum bounding box region including the opaque region are combined to generate an image compression stream used as a user interface. In general, a head capable of distinguishing an area of a stream may include head signature and stream length information.

The video resource compression streams for the user interface generated by the method are stored in the resource storage unit 50 in the embedded device, and when the embedded device is activated, it is decoded and used as the video resource when outputting the user interface.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention without departing from the spirit of the present invention as claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

1 is a view schematically showing an embedded system according to the present invention.

2 is a flowchart illustrating an image processing method by the embedded system of FIG. 1.

3 is a diagram illustrating an example of a transparent region and a non-transparent region of an input image during a lossless image compression process according to the present invention.

4 is a diagram illustrating an example of configuring a transparency bitmap for the input image of FIG. 3.

FIG. 5 is a diagram illustrating an example of setting a minimum bounding box to perform lossy compression on the input image of FIG. 3.

Claims (9)

A transparency bitmap generator configured to generate a transparency bitmap by designating a specific color among the color information of the input color image as a transparent color; A minimum bounding box setting unit configured to set a minimum bounding box area including a non-transparent area based on the transparency bitmap generated by the transparency bitmap generator; A compression unit configured to compress the transparency bitmap generated by the transparency bitmap generation unit using a lossless compression method and to perform JPEG loss compression on the minimum bounding box area set by the minimum bounding box setting unit; And A compressed stream generating unit for generating a compressed stream by combining the lossless compressed stream and the lost compressed stream compressed by the compression unit, The compression unit, And a JPEG loss compression by allocating a pixel value of a boundary area of a non-transparent area adjacent to the transparent area to a transparent area within the minimum bounding box area. The method of claim 1, Embedded system further comprises a storage unit for storing the image resource compressed by the compression unit. delete The method according to claim 1 or 2, The compression unit, Embedded system, characterized in that to block and code the transparency bitmap to increase the compression efficiency of the transparency bitmap. delete In the image processing method of the embedded system to increase the image compression efficiency, Generating a transparency bitmap using color information of an input color image; Setting a minimum bounding box area including a non-transparent area based on the generated transparency bitmap; Compressing the generated transparency bitmap using a lossless compression method and lossy compressing the set minimum bounding box area; And Combining the lossless compressed stream and the lost compressed stream compressed by the compression step to generate a compressed stream, Lossy compressing the minimum bounding box area, JPEG loss compression by assigning a pixel value of a boundary area of a non-transparent area adjacent to the transparent area to a transparent area within the minimum bounding box area. The method of claim 6, And storing the compressed video resource stream generated by the compressed stream generating step. delete The method according to claim 6 or 7, Blocking and coding the transparency bitmap to increase compression efficiency of the transparency bitmap, An image processing method of an embedded system, characterized by lossless compression of the blocked and coded transparency bitmap.

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