KR102037962B1 - Systems, Methods, and Computer-Readable Mediums for Visually Lossless Image Compression of Medical Images - Google Patents

Abstract

The present invention relates to a system, a method, and a computer-readable medium for visually lossless image compression of a medical image. The system comprises: a pre-processing unit configured to perform pre-processing on an original image including a plurality of original image pixels in a predetermined pre-processing direction to generate a pre-processed image including a plurality of pre-processed image pixels; a predictor unit configured to calculate a prediction error of the pre-processed image pixels based on an adjacent pre-processed image pixel adjacent to a predetermined prediction direction, with respect to each of the pre-processed image pixels; an entropy encoder configured to generate a compressed image of which lossless compression has been performed based on the prediction error and the pre-processed image; a parameter input unit configured to input parameters with respect to the method of generating the pre-processed image and the method of calculating the prediction error; and a control unit configured to control the pre-processing unit and the prediction unit based on the parameters. According to the present invention, it is possible to increase a compression rate of visually lossless compression by performing pre-processing before performing the visually lossless compression on an original image.

Description

System, Methods, and Computer-Readable Mediums for Visually Lossless Image Compression of Medical Images}

An image compression system, method, and computer-readable medium for visual lossless compression of medical images, more particularly comprising a plurality of preprocessing image pixels by performing preprocessing on an original image comprising a plurality of original image pixels An image compression system, method, and computer-readable medium for visual lossless compression of a medical image, generating a preprocessed image and performing lossless compression based on the generated preprocessed image.

With the development of CMOS image sensors, the development of mass storage devices has increased the importance of the storage and management of medical digital images through medical devices including CT, MRI, and X-ray equipment.

In particular, in the case of lossless compression of medical images, there is less data loss than lossy compression, but the method of controlling the compression ratio of medical images according to the digitization of analog medical images and high quality medical images There is a growing need for.

An object of the present invention is to perform a preprocessing for the original image including a plurality of original image pixels to generate a preprocessed image including a plurality of preprocessed image pixels, and to perform a lossless compression based on the generated preprocessed image, An image compression system, method, and computer-readable medium for visual lossless compression of an image are provided.

In order to solve the above problems, in an embodiment of the present invention, as an image compression system for visual lossless compression of a medical image, pre-processing in the pre-processing direction is set for the original image including a plurality of original image pixels A preprocessing unit to generate a preprocessing image including a plurality of preprocessing image pixels; For each preprocessing image pixel, a predictor unit for calculating a prediction error of the preprocessing image pixel based on adjacent preprocessing image pixels in a set prediction direction; An entropy encoder for generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image; A parameter input unit for inputting parameters for the preprocessing image generation method and the prediction error calculation method; And a controller configured to control the preprocessor and the predictor based on the parameter.

In one embodiment of the present invention, the plurality of original image pixels includes one or more original image pixel groups having a base unit of n original image pixels continuous in the preprocessing direction, and the preprocessing unit includes each original image. Performing a preprocessing on the pixel group, using any one of the n original image pixels as a reference pixel, and based on the difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel, You can change the pixel value for the rest of the original image pixels.

In one embodiment of the present invention, when the difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel is less than a predetermined threshold with respect to the rest of the n original image pixels, The remaining pixel value of the n original image pixels may be changed to the pixel value of the reference pixel.

In one embodiment of the present invention, the preprocessing direction is a first direction for changing the x-axis value of the pixel, a second direction for changing the y-axis value of the pixel, and a change in the x-axis value and the y-axis value of the pixel. May include a third direction.

In an embodiment of the present invention, the parameter includes information on the preprocessing direction and information on the number of pixels of the original image pixel group, and the controller sets a prediction direction corresponding to the preprocessing direction, Can input to the predictor part.

In an embodiment of the present disclosure, the parameter may further include information on the preset threshold, and the preprocessor may perform preprocessing based on the preset threshold included in the parameter.

In order to solve the above problems, in an embodiment of the present invention, as an image compression method for visual lossless compression of a medical image, preprocessing in a preprocessing direction set for an original image including a plurality of original image pixels A preprocessing step of generating a preprocessing image including a plurality of preprocessing image pixels; For each preprocessing image pixel, calculating a predictive error of the preprocessing image pixel based on adjacent preprocessing image pixels in a set prediction direction; An entropy encoder step of generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image; A parameter input step of inputting parameters for the preprocessing image generation method and the prediction error calculation method; And a control step of controlling the preprocessor and the predictor based on the parameter.

In one embodiment of the present invention, the plurality of original image pixels includes at least one original image pixel group having a base unit of n original image pixels continuous in the preprocessing direction, and the preprocessing step includes: Performing preprocessing on the image pixel group, using any one of the n original image pixels as a reference pixel, and based on a difference between the pixel value of the remaining pixel values of the n original image pixels and the pixel value of the reference pixel, You can change the pixel value of the rest of the n original image pixels.

In one embodiment of the present invention, the preprocessing step, when the difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel is less than a predetermined threshold for the rest of the n original image pixels. The remaining pixel value of the n original image pixels may be changed to the pixel value of the reference pixel.

In order to solve the above problems, in one embodiment of the present invention, a computer-readable medium for implementing an image compression method for visual lossless compression of a medical image, the computer-readable medium, a computing device Stores instructions for performing the following steps, wherein the steps include: performing preprocessing in a preprocessing direction set for an original image including a plurality of original image pixels to generate a preprocessed image including a plurality of preprocessed image pixels Pretreatment step; For each preprocessing image pixel, calculating a predictive error of the preprocessing image pixel based on adjacent preprocessing image pixels in a set prediction direction; An entropy encoder step of generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image; A parameter input step of inputting parameters for the preprocessing image generation method and the prediction error calculation method; And a control step of controlling the preprocessor and the predictor based on the parameters.

According to an embodiment of the present invention, the pre-processing is performed before performing the visual lossless compression on the original image, thereby increasing the compression ratio of the visual lossless compression.

According to an embodiment of the present invention, in performing the preprocessing on the original image, data loss may be reduced by performing different preprocessing according to the visual lossless compression method of the image compression system.

According to an embodiment of the present invention, in performing the preprocessing on the original image, there is an effect of increasing the compression efficiency by performing different preprocessing according to the visual lossless compression method of the image compression system.

According to an embodiment of the present invention, in performing preprocessing on an original image, data loss is reduced or compression efficiency is adjusted by adjusting a predetermined threshold for a difference between a pixel value of an adjacent original image pixel as a reference. It can increase the effect.

According to an embodiment of the present invention, in performing the preprocessing on the original image, it is possible to reduce the data loss or increase the speed of the entire operation by adjusting the number of pixels of the original image pixel group to be preprocessed. have.

1 schematically illustrates an operating environment of an image compression system for visual lossless compression of a medical image according to an embodiment of the present invention.
2 schematically illustrates an internal configuration of an image compression system according to an embodiment of the present invention.
3 exemplarily illustrates an original image and a preprocessed image according to an embodiment of the present invention.
4 exemplarily illustrates an operation of the preprocessor according to the first direction according to an embodiment of the present invention.
5 exemplarily illustrates an operation of the preprocessor according to the third direction according to an exemplary embodiment.
6 exemplarily illustrates an operation of the preprocessor according to the second direction according to an embodiment of the present invention.
7 schematically illustrates the connection of an internal configuration of an image compression system according to an embodiment of the present invention.
8 exemplarily illustrates an original image and a compressed image by an operation of an image compression system according to an embodiment of the present invention.
9 illustrates an enlarged original image and a compressed image according to an embodiment of the present invention.
10 exemplarily shows an internal configuration of an image compression system according to an embodiment of the present invention.

In the following, various embodiments and / or aspects are now disclosed with reference to the drawings. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more aspects. However, it will also be appreciated by one of ordinary skill in the art that this aspect (s) may be practiced without these specific details. The following description and the annexed drawings set forth in detail certain illustrative aspects of the one or more aspects. However, these aspects are exemplary and some of the various methods in the principles of the various aspects may be used and the descriptions described are intended to include all such aspects and their equivalents.

Moreover, various aspects and features will be presented by a system that may include a number of devices, components, and / or modules, and the like. The various systems may include additional devices, components, and / or modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in connection with the drawings. It must be understood and recognized.

As used herein, “an embodiment”, “an example”, “aspect”, “an example”, etc., may not be construed as having any aspect or design described being better or advantageous than other aspects or designs. . The terms '~ part', 'component', 'module', 'system', 'interface', etc. used generally mean a computer-related entity, for example, hardware, hardware And a combination of software and software.

In addition, the terms "comprises" and / or "comprising" mean that such features and / or components are present, but exclude the presence or addition of one or more other features, components, and / or groups thereof. It should be understood that it does not.

In addition, terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

In addition, in the embodiments of the present invention, unless otherwise defined, all terms used herein including technical or scientific terms are generally understood by those skilled in the art to which the present invention belongs. Has the same meaning as Terms such as those defined in the commonly used dictionaries should be interpreted as having meanings consistent with the meanings in the context of the related art, and ideally or excessively formal meanings, unless explicitly defined in the embodiments of the present invention. Not interpreted as

The present invention provides an image compression system, method, and computer-readable medium for visual lossless compression of medical images, comprising preprocessing an original image including a plurality of original image pixels to include a plurality of preprocessed image pixels. A preprocessed image is generated and lossless compression is performed based on the generated preprocessed image.

Hereinafter, an image compression system for visual lossless compression of such medical images will be described.

1 schematically illustrates an operating environment of an image compression system for visual lossless compression of a medical image according to an embodiment of the present invention.

According to the exemplary embodiment, the image compression system 100 may generate the compressed image based on the input original image.

However, before the image compression system 100 performs the visual lossless compression on the original image, the image compression system 100 performs the preprocessing on the original image to generate the preprocessed image and the losslessness on the generated preprocessed image. The compressed image may be generated by performing compression.

That is, the image compression system 100 may increase the compression efficiency of the visual lossless compression while minimizing the loss of data representing the finally generated compressed image by performing preprocessing on the original image. .

However, as will be described later, the preprocessing method performed on the original image in the image compression system 100 may be performed according to a lossless compression method performed on the preprocessed image in the image compression system 100. have.

The original image may include an analog image obtained from a medical imaging apparatus such as MRI, CT, and X-ray, etc., into a digital image, or a digital image itself obtained from a digital medical imaging apparatus. This original image is an image expressed in gray-scale and may have an extension of DICOM (DCM).

In addition, the compressed image may have an extension including the JPEG, JPEG 2000, run-legth encoding (RLE) by performing visual lossless compression on the extension of the DICOM (DCM) from the original image.

As a result, the image compression system 100 performs the visual lossless compression on the original image, which is a medical image having a DICOM (DCM) extension expressed in gray-scale, thereby generating the compressed image having an extension such as JPEG. can do.

In addition, in one embodiment of the present invention, the original image represented by the gray-scale is represented by a value of 0 to 255 corresponding to a value of 8 bits, or 0 to a corresponding value of 16 bits. It can be represented by the value of 65535. However, the number of bits per pixel for the original image is not dependent and can be variously applied.

2 schematically illustrates an internal configuration of an image compression system according to an embodiment of the present invention.

The computing device may include a processor A, a bus (corresponding to a double-headed arrow between the processor, memory, network interface portion), a network interface B, and a memory C. The memory C may include an operating system, processor execution code, original image information, and compressed image information.

The processor A may include a preprocessor 1000, a predictor 2000, an entropy encoder 3000, a controller 4000, and a parameter input unit 5000. In other embodiments, the image compression system 100 may include more components than those of FIG. 2.

The memory C is a computer-readable recording medium, and may include a permanent mass storage device such as random access memory (RAM), read only memory (ROM), and a disk drive. In addition, the memory C may store program codes for the operating system and the processor execution code. These software components may be loaded from a computer readable recording medium separate from the memory C using a drive mechanism (not shown). Such a separate computer-readable recording medium may include a computer-readable recording medium (not shown) such as a floppy drive, a disk, a tape, a DVD / CD-ROM drive, a memory card, and the like. In other embodiments, software components may be loaded into the memory C via the network interface B rather than a computer readable recording medium.

The bus may enable communication and data transmission between components of a computing device that performs the image compression system 100. The bus may be configured using a high-speed serial bus, a parallel bus, a storage area network and / or other suitable communication technology.

The network interface unit B may be a computer hardware component for connecting a computing device that performs the image compression system 100 to a computer network. The network interface B may connect the image compression system 100 to the computer network through a wireless or wired connection. Through the network interface unit B, a computing device performing an image optimization method for a medical image may be wirelessly or wiredly connected to another electronic device.

The processor A may be configured to process instructions of a computer program by performing input / output operations of an image optimization method for basic arithmetic, logic, and medical images. Instructions may be provided to the processor A by the memory C or by the network interface unit B and via the bus. The processor A may be configured to execute program codes for the preprocessor 1000, the predictor 2000, the entropy encoder 3000, the controller 4000, and the parameter input unit 5000. Can be. Such program code may be stored in a recording device such as the memory C.

The preprocessor 1000, the predictor 2000, the entropy encoder 3000, the controller 4000, and the parameter input unit 5000 implement the image compression system 100 to be described below. It can be configured for. In the processor A, some components may be omitted, additional components not shown, or two or more components may be combined according to the image compression system 100.

On the other hand, such a computing device preferably corresponds to a personal computer or a server, and in some cases, a smart phone, a tablet, a mobile phone, a video phone, an e-book reader (e) -book reader, desktop PC, laptop PC, netbook PC, personal digital assistant (PDA), portable Portable multimedia player (PMP, hereinafter referred to as 'PMP'), MP3 player, mobile medical device, camera, wearable device (e.g., head-mounted) Head-mounted device (HMD), for example referred to as 'HMD', electronic clothing, electronic bracelet, electronic necklace, electronic accessory, electronic tattoo, or smart watch ) And the like.

According to the embodiment, the image compression system 100 is a pre-processing unit for generating a pre-processing image including a plurality of pre-processing image pixels by performing a pre-processing in the pre-processing direction set for the original image including a plurality of original image pixels ( 1000); A predictor 2000 for each preprocessing image pixel, for calculating a prediction error of the preprocessing image pixel based on adjacent preprocessing image pixels in the set prediction direction; An entropy encoder 3000 generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image; A parameter input unit 5000 for inputting parameters for the preprocessing image generation method and the prediction error calculation method; And a controller 4000 for controlling the preprocessor and the predictor based on the parameter.

Preferably, the plurality of original image pixels may include one or more original image pixel groups based on n original image pixels continuous in the preprocessing direction.

In particular, the preprocessing unit constituting the image compression system 100 performs the preprocessing on the original image including the plurality of original image pixels as described above, and the preprocessing includes a plurality of preprocessing image pixels. Create an image.

In addition, the predictor 2000 and the entropy encoder 3000 constituting the image compression system 100 may perform lossless compression on the preprocessed image generated by the preprocessing in the preprocessor 1000. To generate the compressed image.

That is, before the lossless compression of the predictor 2000 and the entropy encoder 3000 is performed on the original image input to the image compression system 100, the preprocessing unit may be applied to the original image. The preprocessing image is generated by performing the preprocessing of 1000).

In particular, the preprocessing unit 1000 is inputted so as to correspond to a method of calculating a prediction error according to a prediction direction in the predictor 2000 as described below in order to perform visual lossless compression. It is preferable to perform pretreatment for.

In addition, the preprocessing performed by the preprocessor 1000 is based on the original image uploaded to the volatile memory or the like so that the pixel value of the pixel that has been preprocessed is not affected by the pixel value of the pixel which has been preprocessed. Preference is given to performing.

Hereinafter, a description will be given of a method of calculating a prediction error according to the prediction direction in the predictor 2000.

3 exemplarily illustrates an original image and a preprocessed image according to an embodiment of the present invention.

According to the above embodiment, the plurality of original image pixels may include one or more original image pixel groups based on n original image pixels continuous in the preprocessing direction.

As shown in FIG. 3A, the preprocessing image 20 including a plurality of preprocessing image pixels input to the predictor 2000 includes one preprocessing image pixel 21 and adjacent thereto. It can be divided into a plurality of adjacent pre-processing image pixels 22.

Preferably, the plurality of preprocessing image pixels 22 includes a first neighboring preprocessing image pixel adjacent to a prediction direction on the left side of the preprocessing image pixel 21, a second neighboring preprocessing image pixel on a left diagonal prediction direction, and And a third neighboring processed image pixel adjacent to an upper prediction direction.

According to the embodiment, the predictor 2000 may calculate the prediction error of the preprocessing image pixel based on the adjacent preprocessing image pixel adjacent to each of the preprocessing image pixels in the set prediction direction.

Specifically, as shown in (b) of FIG. 3, when the prediction error is calculated according to the adjacent preprocessing image pixel adjacent in the set 1 prediction direction, the predictor 2000 performs the preprocessing image pixel 21. And a prediction error based on the first neighboring preprocessing image pixel adjacent to the left in the prediction direction among a plurality of adjacent preprocessing image pixels 22 adjacent to the preprocessing image pixel.

The prediction error calculation method is a result of the prediction unit 2000 performing prediction on the preprocessing image pixel 21 according to the pixel value D of the preprocessing image pixel 21 and the prediction type of 1. The difference between the pixel values C of the first neighboring processed image pixels may be calculated.

As shown in (b) of FIG. 3, when the prediction error is calculated according to adjacent adjacent preprocessed image pixels using the set 2 predictive type, the predictor 2000 includes the preprocessed image pixel 21 and the A prediction error may be calculated based on the second adjacent preprocessing image pixel adjacent in the prediction direction of the left diagonal line among the plurality of adjacent preprocessing image pixels 22 adjacent to the preprocessing image pixel.

The prediction error calculation method is a result of the prediction unit 2000 performing prediction on the preprocessing image pixel 21 according to the pixel value D of the preprocessing image pixel 21 and the prediction type of 2. The difference in pixel value A of the second neighboring processed image pixel may be calculated.

As shown in (b) of FIG. 3, when the prediction error is calculated according to the adjacent preprocessing image pixel adjacent to the set prediction direction of 3, the predictor 2000 includes the preprocessing image pixel 21 and the A prediction error may be calculated based on the third neighboring preprocessing image pixel adjacent to an upper prediction direction among a plurality of adjacent preprocessing image pixels 22 adjacent to the preprocessing image pixel.

The prediction error calculation method is a result of the prediction unit 2000 performing prediction on the preprocessing image pixel 21 according to the pixel value D of the preprocessing image pixel 21 and the prediction type of 2. The difference between the pixel values B of the third neighboring processed image pixels may be calculated.

As a result, the predictor 2000 predicts the preprocessed image 20 according to a prediction direction set based on a parameter for the method of calculating the prediction error input by the user to the parameter input unit 5000. The error can be calculated.

The entropy encoder 3000 may perform lossless compression based on the prediction error and the preprocessed image calculated by the predictor 2000 in the same manner as described above. However, as the value of the prediction error input to the entropy encoder 3000 approaches 0, the compression ratio of the lossless compression may increase.

To this end, as described above, the preprocessor 1000 may perform preprocessing on the original image by different preprocessing types and preprocessing directions according to a method of calculating a prediction error in the predictor 2000. have.

That is, according to the embodiment, the preprocessing unit 1000 may generate a preprocessing image including a plurality of preprocessing image pixels by performing preprocessing in a preprocessing direction set for the original image including the plurality of original image pixels. .

Preferably, the preprocessing unit 1000 performs preprocessing on each original image pixel group, and sets any one of the n original image pixels as a reference pixel, and the remaining pixel values of the n original image pixels. Based on the difference between the pixel values of and the reference pixel, the pixel values of the remaining of the n original image pixels may be changed.

Specifically, as shown in FIG. 3C, when the prediction error is calculated according to the prediction direction of 1 set in the predictor 2000, the original image 10 input to the preprocessor 1000 is calculated. ) Includes one or more original image pixel groups 11 based on four original image pixels contiguous in the preprocessing direction corresponding to the prediction direction, and the preprocessor 1000 performs preprocessing based on the original image pixel group 11. Can be.

However, in FIG. 3C, only one original image pixel group 11 continuous in the preprocessing direction corresponding to the set prediction direction is shown, but in practice, the original image 10 is continuous in the preprocessing direction on the left side. It can consist of one or more original image pixel groups.

In addition, as shown in (c) of FIG. 3, when the prediction error is calculated according to the prediction direction of 2 set in the predictor 2000, the original image 10 input to the preprocessor 1000 is calculated. Includes at least one original image pixel group 12 having a base unit of four original image pixels contiguous in the preprocessing direction corresponding to the set prediction direction, and the preprocessor 1000 performs preprocessing based on the original image pixel group 12. Can be.

However, in FIG. 3C, only one original image pixel group 12 that is continuous in the preprocessing direction corresponding to the set prediction direction is shown, but in reality, the original image 10 is arranged in the left diagonal preprocessing direction. It can consist of one or more original image pixel groups.

As shown in FIG. 3C, when the prediction error is calculated according to the prediction direction of 3 set by the predictor 2000, the original image 10 input to the preprocessor 1000 is set. At least one original image pixel group 13 based on four original image pixels consecutive in the preprocessing direction corresponding to the prediction direction may be included, and the preprocessor 1000 may perform preprocessing based on the original image pixel group 13. .

However, in FIG. 3C, only one original image pixel group 13 that is continuous in the preprocessing direction corresponding to the set prediction direction is shown, but in practice, the original image 10 is continuous in the upper preprocessing direction. It may consist of one or more original image pixel groups.

As a result, the preprocessing direction of the original image is preferably set to correspond to the prediction direction of the preprocessed image for calculating a prediction error in the predictor 2000.

Alternatively, the prediction direction of the preprocessed image may be set to correspond to the preprocessing direction of the original image to be preprocessed by the preprocessor 1000.

According to the embodiment, the preprocessing direction is a first direction for changing the x-axis value of the pixel, a second direction for changing the y-axis value of the pixel, and a second for changing the x-axis value and the y-axis value of the pixel. It can include three directions.

The first direction corresponds to the pretreatment direction on the left side described above, the second direction corresponds to the pretreatment direction on the upper side described above, and the third direction corresponds to the pretreatment direction on the left diagonal line described above.

4 exemplarily illustrates an operation of the preprocessor according to the first direction according to an embodiment of the present invention.

Preferably, the preprocessing unit 1000 performs preprocessing on each original image pixel group, sets any one of the n original image pixels as a reference pixel, and the remaining pixels of the n original image pixels. Based on the difference between the value and the pixel value of the reference pixel, the pixel value of the rest of the n original image pixels may be changed.

Specifically, as shown in (a) of FIG. 4, a left side set as a reference pixel among four original image pixels constituting the original image pixel group having four original image pixels consecutive in a first direction as a basic unit Based on the difference between the pixel value 10 of the last original image pixel and the pixel values 15, 30, and 15 of each of the remaining original image pixels, preprocessing may be performed on each of the remaining original image pixels.

As described above, the first direction in which the preprocessing is performed in the preprocessor 1000 is set to correspond to the prediction direction in which the prediction error is calculated in the predictor 2000.

Alternatively, the prediction direction in which the prediction error is calculated in the predictor 2000 may be set to correspond to the first direction in which the preprocessing is performed in the preprocessor 1000.

5 exemplarily illustrates an operation of the preprocessor according to the third direction according to an exemplary embodiment.

In addition, as shown in (a) of FIG. 5, an end portion of the four original image pixels constituting the original image pixel group having four original image pixels continuous in a third direction as a base unit is set as a reference pixel. Based on the difference between the pixel value 10 of the original image pixel and the pixel values 15, 30, 15 of each of the remaining original image pixels, preprocessing may be performed on each of the remaining original image pixels.

As described above, the third direction in which the preprocessing is performed in the preprocessor 1000 may be set to correspond to the prediction direction in which the prediction error is calculated in the predictor 2000.

Alternatively, the prediction direction in which the prediction error is calculated in the predictor 2000 may be set to correspond to a third direction in which the preprocessing is performed in the preprocessor 1000.

6 exemplarily illustrates an operation of a preprocessor according to an upper preprocessing direction according to an embodiment of the present invention.

In addition, as shown in (a) of FIG. 6, an upper side set as a reference pixel among four original image pixels constituting the original image pixel group having four original image pixels consecutive in a second direction as a basic unit. Based on the difference between the pixel value 10 of the original image pixel at the end and the pixel values 15, 30, 15 of each of the remaining original image pixels, preprocessing may be performed on each of the remaining original image pixels.

As described above, the second direction in which the preprocessing is performed in the preprocessor 1000 may be set to correspond to the prediction direction in which the prediction error is calculated in the predictor 2000.

Alternatively, the prediction direction in which the prediction error is calculated in the predictor 2000 may be set to correspond to the second direction in which the preprocessing is performed in the preprocessor 1000.

More preferably, when the difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel is less than or equal to a predetermined threshold with respect to the rest of the n original image pixels, the preprocessing unit 1000. The remaining pixel value of the n original image pixels may be changed to the pixel value of the reference pixel.

Specifically, as shown in (b) of FIG. 4, when the preset threshold is 10, the preprocessing unit 1000 may perform remaining pixel values 15, 30, and 15 of the four original image pixels. May be changed to the pixel value 10 of the reference pixel.

That is, the pixel values of the original image pixels positioned first and third of the remaining pixel values among the four original image pixels are converted into pixel values of the reference pixel, whereby the pixel values are changed to (10, 30, 10) and stored. Can be.

Specifically, the pretreatment may be performed in the same manner as in FIGS. 5B and 6B.

As described above, the preprocessor 1000 and the predictor 2000 may be configured such that the preprocessing direction and the prediction direction correspond to each other, thereby performing preprocessing and calculating a prediction error.

Hereinafter, a method of performing preprocessing in the preprocessor 1000 and a method of calculating a prediction error in the predictor 2000 based on a parameter input by the user to the parameter input unit 5000 is set. The configuration to be described.

7 schematically illustrates the connection of an internal configuration of an image compression system according to an embodiment of the present invention.

Specifically, the parameter input unit 5000 may input parameters for the method for generating the preprocessed image and the method for calculating the prediction error.

That is, the user may input a parameter for the method of calculating the prediction error including the prediction direction as described above in the parameter input unit 5000. In addition, a user may input a parameter for generating the preprocessed image to the parameter input unit 5000.

According to an embodiment of the present invention, when a parameter for the method of calculating the prediction error including the prediction direction is input to the parameter input unit 5000, the parameter input unit 5000 determines the preprocessing direction based on the parameter. A parameter for generating the preprocessing image may be generated.

Preferably, the parameter may include information about the prediction direction, information about the preprocessing direction, information about the predetermined threshold, and information about n value.

In the case of the method of generating the preprocessed image including the preprocessing direction, the parameter may be set to correspond to the method of calculating the prediction error including the prediction direction. Alternatively, in the prediction error calculation method including the prediction direction, a parameter may be set to correspond to the preprocessing image generation method including the preprocessing direction.

According to the embodiment, the controller 4000 may generate a control signal for the method for generating the preprocessed image and the method for calculating the prediction error based on the parameter.

That is, the controller 4000 receives a parameter input by a user from the parameter input unit 5000, and generates a control signal for the method of generating the preprocessed image in the preprocessor 1000 based on the parameter input by the user. The dictator 2000 may generate a control signal for the method of calculating the prediction error.

As such, each control signal generated by the controller 4000 may be input to the preprocessor 1000 and the predictor 2000.

As a result, the preprocessing unit 1000 generates the preprocessing image 20 by performing preprocessing on the original image 10 based on a control signal input from the control unit 4000, and the predator unit ( 2000).

In addition, the predictor 2000 calculates the prediction error by performing preprocessing on the preprocessing image 20 based on a control signal input from the control unit 4000, and then calculates the predictive error to the entropy encoder 3000. You can enter

The entropy encoder 3000 may perform lossless compression based on the prediction error and the preprocessed image.

Hereinafter, the operation of the components of the image compression system 100 according to the parameter will be described.

According to the embodiment, the parameter includes information on the preprocessing direction and information on the number of pixels of the original image pixel group, and the control unit sets a prediction direction corresponding to the preprocessing direction, and the predic It can be input to the touch part 2000.

Alternatively, the parameter may include information about the prediction direction and information about the number of pixels of the original image pixel group, and the controller sets a preprocessing direction corresponding to the prediction direction, and transmits the preprocessing direction to the preprocessor 1000. You can enter

As a result, the control unit 5000 sets a prediction direction corresponding to the preprocessing direction and inputs the prediction direction to the predictor 2000 or sets a preprocessing direction corresponding to the prediction direction. By inputting to, the compression efficiency of the lossless compression finally performed by the entropy encoder 3000 can be increased.

In addition, the user may adjust the speed of visual lossless compression of the original image and the data loss rate of visual lossless compression of the original image through information on the number of pixels of the original image pixel group. The speed and the data loss rate are in a trade-off relationship with each other.

That is, as the user sets the information on the number of pixels of the original image pixel group to a larger value, the number of pixels to perform preprocessing in one operation increases, thereby increasing the speed of visual lossless compression of the original image. Can be.

On the other hand, as the user sets the information on the number of pixels of the original image pixel group to a larger value, the original image pixel constituting the original image pixel group according to the reference pixel even though they are not adjacent to each other. The pixel value of can be converted, so that the data loss rate of visual lossless compression on the original image can be increased.

Preferably, the parameter may further include information on the preset threshold, and the preprocessor 1000 may perform preprocessing based on the preset threshold included in the parameter.

The user may adjust the compression ratio of the visual lossless compression on the original image and the data loss ratio of the visual lossless compression on the original image through the parameter including the information on the preset threshold. The compression rate and the data loss rate are in a trade-off relationship with each other.

That is, as the user sets the preset threshold to a larger value based on a parameter including information on the preset threshold, preprocessing is performed among a plurality of original image pixels constituting the original image, thereby converting the data value. The number of original image pixels to be increased. That is, for this reason, the data loss rate of visual lossless compression on the original image can be increased.

On the contrary, as the user sets the preset threshold to a large value, preprocessing is performed among a plurality of original image pixels constituting the original image, thereby increasing the number of original image pixels to which data values are converted. The compression rate of visual lossless compression can be increased.

As a result, the user can adjust the compression ratio of the visual lossless compression on the original image and the data loss ratio of the visual lossless compression on the original image by adjusting the predetermined threshold through the third parameter.

According to an embodiment of the present invention, the reference pixel selects one original image pixel having the largest pixel value among the pixel values of each of the n original image pixels, or one original image pixel having the smallest pixel value. Select an original image pixel having an intermediate pixel value, or select an original image pixel among one of the original image pixels positioned at both ends of the original image pixel group, or in the middle of the original image pixel group It can be set by the user by selecting the original image pixels located at.

Such a predetermined method may be set by the user in consideration of the compression rate, data loss rate, or calculation speed of visual lossless compression to be performed.

Preferably, the parameter may include information on a method of setting the reference pixel, and the controller 1000 may perform preprocessing based on a predetermined threshold included in the parameter.

However, even when the preprocessing is performed based on the fifth parameter of the preset method in the control unit 1000 as described above, the preprocessing performed corresponds to the method of calculating the prediction error in the predictor 2000. It is preferred to be set to.

8 exemplarily illustrates an original image and a compressed image by an operation of an image compression system according to an embodiment of the present invention.

According to the embodiment, Figure 8 is input to the image compression system (a), (c), (e), and (g) each of the gray scale medical original image having a DICOM (DCM) extension located on the left side The compressed images (b), (d), (f), and (h) generated by the above are shown.

(A), which is a medical original image having a capacity of 3666 KB, is converted into a compressed image (b) having a capacity of 2051 KB by the operation of the image compression system, and is generated as a medical original image having a capacity of 3374 KB ( c) is converted into (d), which is a compressed image having a capacity of 1873 KB by the operation of the image compression system, and (e) is a medical original image having a capacity of 986 KB (e) by the operation of the image compression system (G) which is converted to (f) which is a compressed image having a capacity of 547 KB and is a medical original image having a capacity of 6351 KB, is a compressed image having a capacity of 3319 KB by operation of the image compression system (b). Is converted to).

By the operation of the image compression system, the compression rate for the medical original image (a) has a compression ratio of 55.9%, the compression rate for the medical original image (c) has a compression ratio of 55.5%, and the medical original image (e). Has a compression rate of 55.5%, and the compression ratio for the medical original image (g) shows a compression rate of 52.3%.

In this compression ratio, as shown in FIG. 8, the original image and the compressed image do not show a difference that can be visually identified.

9 illustrates an enlarged original image and a compressed image according to an embodiment of the present invention.

According to the embodiment, (a) of FIG. 9 shows a result obtained by enlarging a part of (e) of FIG. 8, which is an original image, at a magnification of 501%, and (b) of FIG. The result of enlarging a part of f) by the same 501% magnification is shown.

As shown in (a) and (b) of FIG. 9, it can be seen that the original image and the compressed image do not show a difference that can be visually identified even though the magnification is 501%.

10 exemplarily shows an internal configuration of an image compression system according to an embodiment of the present invention.

The image compression system according to the above embodiment may be implemented by the computing device 11000 illustrated in FIG. 10.

As shown in FIG. 10, the computing device 11000 may include at least one processor 11100, a memory 11200, a peripheral interface 11300, and an input / output subsystem ( I / Osubsystem 11400, power circuit 11500, and communication circuit 11600.

The memory 11200 may include, for example, high-speed random access memory, magnetic disk, SRAM, DRAM, ROM, flash memory, or nonvolatile memory. have. The memory 11200 may include a software module, an instruction set, or other various data necessary for the operation of the computing device 11000.

In this case, accessing the memory 11200 from another component such as the processor 11100 or the peripheral device interface 11300 may be controlled by the processor 11100.

The peripheral interface 11300 may couple the input and / or output peripherals of the computing device 11000 to the processor 11100 and the memory 11200. The processor 11100 may execute a software module or an instruction set stored in the memory 11200 to perform various functions for the computing device 11000 and process data.

Input / output subsystem 11400 may couple various input / output peripherals to peripheral interface 11300. For example, the input / output subsystem 11400 may include a controller for coupling a peripheral device such as a monitor or keyboard, a mouse, a printer, or a touch screen or a sensor, as necessary, to the peripheral interface 11300. According to another aspect, the input / output peripherals may be coupled to the peripheral interface 11300 without passing through the input / output subsystem 11400.

The power circuit 11500 may supply power to all or part of the components of the terminal. For example, power circuit 11500 may include a power management system, one or more power sources such as batteries or alternating current (AC), charging systems, power failure detection circuits, power converters or inverters, power status indicators or power sources. It can include any other components for creation, management, distribution.

The communication circuit 11600 may enable communication with another computing device using at least one external port.

Alternatively, as described above, the communication circuit 11600 may include an RF circuit to transmit and receive an RF signal, also known as an electromagnetic signal, to enable communication with other computing devices.

This embodiment of FIG. 10 is only one example of the computing device 11000, and the computing device 11000 may include some components shown in FIG. 10, or may further include additional components not shown in FIG. 10, or 2. It may have a configuration or arrangement that combines two or more components. For example, a computing device for a communication terminal in a mobile environment may further include a touch screen or a sensor, in addition to the components shown in FIG. 10, and various communication schemes (WiFi, 3G, LTE) in the communication circuit 1160. , Bluetooth, NFC, Zigbee, etc.) may include a circuit for RF communication. Components that may be included in the computing device 11000 may be implemented in hardware, software, or a combination of both hardware and software, including integrated circuits specialized for one or more signal processing or applications.

Methods according to an embodiment of the present invention may be implemented in the form of program instructions that may be executed by various computing devices and may be recorded in a computer readable medium. In particular, the program according to the present embodiment may be configured as a PC-based program or an application dedicated to a mobile terminal. An application to which the present invention is applied may be installed in a user terminal through a file provided by a file distribution system. For example, the file distribution system may include a file transmitter (not shown) for transmitting the file at the request of the user terminal.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the devices and components described in the embodiments are, for example, processors, controllers, arithmetic logic units (ALUs), digital signal processors, microcomputers, field programmable gate arrays (FPGAs). May be implemented using one or more general purpose or special purpose computers, such as a programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of explanation, one processing device may be described as being used, but one of ordinary skill in the art will appreciate that the processing device includes a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as parallel processors.

The software may include a computer program, code, instructions, or a combination of one or more of these, and configure the processing device to operate as desired, or process it independently or in combination. You can command the device. Software and / or data may be any type of machine, component, physical device, virtual equipment, computer storage medium or device for the purpose of interpreting or providing instructions or data to the processing device. Or may be permanently or temporarily embodied in a signal wave to be transmitted. The software may be distributed over networked computing devices so that they are stored or executed in a distributed manner. Software and data may be stored on one or more computer readable recording media.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the media may be those specially designed and constructed for the purposes of the embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine code, such as produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even if replaced or substituted by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims (10)

An image compression system for visual lossless compression of medical images,
A preprocessing unit configured to generate a preprocessing image including a plurality of preprocessing image pixels by performing preprocessing on a preprocessing direction set for the original image including a plurality of original image pixels;
For each preprocessing image pixel, a predictor unit for calculating a prediction error of the preprocessing image pixel based on adjacent preprocessing image pixels in a set prediction direction;
An entropy encoder for generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image;
A parameter input unit for inputting parameters for the preprocessing image generation method and the prediction error calculation method; And
And a controller configured to control the preprocessor and the predictor based on the parameter.
The plurality of original image pixels includes one or more original image pixel groups having a base unit of n original image pixels consecutive in the preprocessing direction,
The preprocessing unit,
Perform preprocessing on each original image pixel group,
One of the n original image pixels is a reference pixel,
Change the pixel value of the remaining of the n original image pixels based on a difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel;
The parameter includes information about the preprocessing direction and information about the number of pixels of the original image pixel group, or includes information about the prediction direction and information about the number of pixels of the original image pixel group;
The control unit sets a prediction direction corresponding to the preprocessing direction and inputs the prediction direction to the predictor unit, or includes information on the number of pixels of the original image pixel group, and the control unit preprocesses corresponding to the prediction direction. Setting an orientation and inputting the orientation to the preprocessing unit.
delete The method according to claim 1,
The preprocessing unit,
For the rest of the n original image pixels,
When the difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel is less than a predetermined threshold, changing the remaining pixel value of the n original image pixels to the pixel value of the reference pixel Compression system.
The method according to claim 1,
The pretreatment direction is,
And a third direction for changing the x-axis value of the pixel, a second direction for changing the y-axis value of the pixel, and a third direction for changing the x-axis value and the y-axis value of the pixel.
delete The method according to claim 3,
The parameter further includes information about the preset threshold,
And the preprocessing unit performs preprocessing based on a predetermined threshold included in the parameter.
Image compression method for visual lossless compression of medical images,
A preprocessing step of generating a preprocessing image including a plurality of preprocessing image pixels by performing preprocessing on a preprocessing direction set for the original image including a plurality of original image pixels;
For each preprocessing image pixel, calculating a predictive error of the preprocessing image pixel based on adjacent preprocessing image pixels in a set prediction direction;
An entropy encoder step of generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image;
A parameter input step of inputting parameters for the preprocessing image generation method and the prediction error calculation method; And
And a control step of controlling the preprocessing step and the predictor step based on the parameter.
The plurality of original image pixels includes one or more original image pixel groups having a base unit of n original image pixels consecutive in the preprocessing direction,
The pretreatment step,
Perform preprocessing on each original image pixel group,
One of the n original image pixels is a reference pixel,
Change the pixel value of the remaining of the n original image pixels based on a difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel;
The parameter includes information about the preprocessing direction and information about the number of pixels of the original image pixel group, or includes information about the prediction direction and information about the number of pixels of the original image pixel group;
The control step sets a prediction direction corresponding to the preprocessing direction and inputs it to the predictor step, or includes information on the number of pixels of the original image pixel group, and the control step corresponds to the prediction direction. Setting a preprocessing direction, and inputting the preprocessing direction to the preprocessing step.
delete The method according to claim 7,
The pretreatment step,
For the rest of the n original image pixels,
When the difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel is less than a predetermined threshold, changing the remaining pixel value of the n original image pixels to the pixel value of the reference pixel Compression method.
A computer-readable medium for implementing an image compression method for visual lossless compression of a medical image, the computer-readable medium storing instructions for causing a computing device to perform the following steps, the steps :
A preprocessing step of generating a preprocessing image including a plurality of preprocessing image pixels by performing preprocessing on a preprocessing direction set for the original image including a plurality of original image pixels;
For each preprocessing image pixel, calculating a predictive error of the preprocessing image pixel based on adjacent preprocessing image pixels in a set prediction direction;
An entropy encoder step of generating a compressed image in which lossless compression is performed based on the prediction error and the preprocessed image;
A parameter input step of inputting parameters for the preprocessing image generation method and the prediction error calculation method; And
And a control step of controlling the preprocessing step and the predictor step based on the parameter.
The plurality of original image pixels includes one or more original image pixel groups having a base unit of n original image pixels consecutive in the preprocessing direction,
The pretreatment step,
Perform preprocessing on each original image pixel group,
One of the n original image pixels is a reference pixel,
Change the pixel value of the remaining of the n original image pixels based on a difference between the remaining pixel value of the n original image pixels and the pixel value of the reference pixel;
The parameter includes information about the preprocessing direction and information about the number of pixels of the original image pixel group, or includes information about the prediction direction and information about the number of pixels of the original image pixel group;
The control step sets a prediction direction corresponding to the preprocessing direction and inputs it to the predictor step, or includes information on the number of pixels of the original image pixel group, and the control step corresponds to the prediction direction. Setting a preprocessing direction and inputting the preprocessing direction to the preprocessing step.

Images