Image storage service providing method, computer program, and computing device

Abstract

To provide an image transcoding technology that enables efficient management of a server storage space in an image storage service.SOLUTION: A method includes the steps of selecting image data in a first format, determining an initial compression parameter for converting image data of a selected first format into a second format, searching for an optimal compression parameter on the basis of whether the image quality of primary image data satisfies a predetermined reference with respect to the primary image data of the second format obtained by transcoding the image data of the selected first format on the basis of the initial compression parameter, transcoding the image data of the selected first format on the basis of the optimum compression parameter and saving the final image data of the second format obtained by transcoding the image data in a memory.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for providing an image storage service performed by a computing device, a computer program, and a computing device. Specifically, the present invention relates to a method for providing an image storage service for efficiently managing user image data stored in a server storage space and providing the image data to the user, a computer program stored on a computer-readable recording medium for causing a computing device to execute the method, and a computing device for executing the method. [Background technology]

[0002] Recently, a number of service providers have been providing cloud storage-based image storage services that store user image data in a server's storage space and transmit the image data stored on the server to the user upon request.

[0003] With the increase in the number of users of image storage services and the widespread use of photographic devices, a huge amount of image data is continuously stored in the server storage space. However, once stored on the server, image data is rarely deleted. Therefore, a solution for efficiently managing the server storage space is required. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an image storage service providing method that can efficiently manage storage space on a server that stores user image data.

[0005] Another object of the present invention is to provide a computing device for performing the image storage service providing method according to the present invention.

[0006] Another object of the present invention is to provide a program stored in a computer-readable recording medium for executing the image storage service providing method according to the present invention.

[0007] The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by a person having ordinary knowledge in the technical field to which the present disclosure pertains (hereinafter referred to as "ordinary engineer") from the following description. [Means for solving the problem]

[0008] According to one aspect of the present invention, a method for providing an image storage service performed by a computing device including at least one processor and a memory includes the steps of selecting image data in a first format, determining initial compression parameters for converting the selected image data in the first format to a second format, searching for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether the image quality of the primary image data satisfies a predetermined standard, and storing in the memory the final image data in the second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters.

[0009] According to another aspect of the present invention, a computing device includes at least one processor and a memory, wherein the processor selects image data in a first format, determines initial compression parameters for converting the selected image data in the first format to a second format, searches for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether the image quality of the primary image data satisfies a predetermined standard, and stores final image data in the second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters in the memory.

[0010] A computer program stored on a computer-readable recording medium according to another aspect of the present invention may be a computer program for executing the image storage service providing method according to the present invention on a computer.

[0011] The above briefly summarized features of the present disclosure are merely exemplary aspects of the detailed description of the present disclosure that follows and are not intended to limit the scope of the present disclosure. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a method for providing an image storage service that can efficiently manage storage space on a server that stores user image data.

[0013] The present invention also provides a computing device that executes the image storage service providing method of the present invention.

[0014] Furthermore, according to the present invention, there can be provided a program stored in a computer-readable recording medium for executing the image storage service providing method according to the present invention.

[0015] The effects obtained by the present disclosure are not limited to those described above, and other effects not described above will be clearly understood by those skilled in the art from the following description. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing an example of a system in which an image storage service according to the present invention is performed; [Figure 2] 1 is a block diagram illustrating an example of the configuration of a user device that uses an image storage service according to the present invention, and a server that provides the image storage service according to the present invention. [Figure 3] 1 is a diagram illustrating a transcoding method according to an embodiment of the present invention; [Figure 4] FIG. 10 is a diagram for explaining an example of a search process for an optimal compression parameter. [Figure 5] FIG. 10 is a diagram for explaining another example of the search process for the optimum compression parameter. [Figure 6] FIG. 2 is a diagram illustrating an example of a method for comparing the image quality of image data in a first format with the image quality of image data in a second format. [Figure 7] FIG. 10 is a diagram showing an example of storing restoration information for image data in a first format. [Figure 8] FIG. 10 is a diagram illustrating an embodiment in which image data stored in a memory is provided in response to a user request. DETAILED DESCRIPTION OF THE INVENTION

[0017] <Summary of the Invention> According to one aspect of the present invention, a method for providing an image storage service performed by a computing device including at least one processor and a memory includes the steps of selecting image data in a first format, determining initial compression parameters for converting the selected image data in the first format to a second format, searching for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether the image quality of the primary image data satisfies a predetermined standard, and storing in the memory the final image data in the second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters.

[0018] In the image storage service providing method according to the present invention, the step of selecting image data in the first format can select any one of at least one first format data that has been stored in the memory for a period of time that is longer than a predetermined period of time as image data in the first format.

[0019] In the image storage service providing method according to the present invention, the initial compression parameters may be determined based on statistics of one or more compression parameters used in previous transcoding.

[0020] In the image storage service providing method according to the present invention, the step of searching for the optimal compression parameters includes the steps of: adjusting the initial compression parameters if the image quality of the primary image data satisfies the predetermined standard; determining whether the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard; and determining the initial compression parameters as optimal compression parameters if the image quality of the secondary image data does not satisfy the predetermined standard, wherein the adjusted compression parameters can have a higher compression rate than the initial compression parameters.

[0021] In the image storage service providing method according to the present invention, the step of searching for the optimal compression parameters includes the steps of: adjusting the initial compression parameters if the image quality of the primary image data does not satisfy the predetermined standard; determining whether the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard; and determining the adjusted compression parameters as optimal compression parameters if the image quality of the secondary image data satisfies the predetermined standard, wherein the adjusted compression parameters can have a lower compression rate than the initial compression parameters.

[0022] In the image storage service providing method according to the present invention, whether the image quality of the primary image data satisfies a predetermined standard can be determined based on whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold value.

[0023] In the image storage service providing method according to the present invention, an image of the image data in the first format and an image of the primary image data in the second format are divided into tiles of a predetermined size, and a determination can be made for each tile as to whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold value.

[0024] In the image storage service providing method according to the present invention, an analysis target is specified for an image of the image data in the first format and an image of the primary image data in the second format using a window of a predetermined size, and a determination as to whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold value can be made by moving the window a predetermined amount.

[0025] The image storage service providing method according to the present invention may include the steps of receiving image data in the first format from a terminal as data to be stored, receiving an input from the terminal requesting transmission of the data to be stored, determining whether the terminal supports the second format, and transmitting final image data in the second format if the terminal supports the second format.

[0026] The image storage service providing method according to the present invention may include the steps of receiving image data in the first format from a terminal as data to be stored, receiving an input from the terminal requesting transmission of the data to be stored, determining whether the terminal supports a second format, and if the terminal does not support the second format, transcoding the final image data in the second format into restored image data in a first format, and then transmitting the restored image data in the first format.

[0027] In the image storage service providing method according to the present invention, the final image data in the second format includes restoration information for the image data in the first format, and when transcoding the final image data in the second format into restored image data in the first format, the restoration information for the image data in the first format can be used.

[0028] In the image storage service providing method according to the present invention, the restoration information of the image data in the first format may include at least one of information regarding a quantization matrix of the first format, information regarding the size of the image in the first format, and SAR (Sample Aspect Ratio) information of the first format.

[0029] According to another aspect of the present invention, a computing device includes at least one processor and a memory, wherein the processor selects image data in a first format, determines initial compression parameters for converting the selected image data in the first format to a second format, searches for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether the image quality of the primary image data satisfies a predetermined standard, and stores final image data in the second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters in the memory.

[0030] In the computing device according to the present invention, the processor can select, as the image data in the first format, any of at least one piece of first format data that has been stored in the memory for a period of time equal to or longer than a predetermined period of time.

[0031] In a computing device according to the present invention, the processor may determine the initial compression parameters based on statistics of one or more compression parameters used in previous transcoding.

[0032] In the computing device according to the present invention, the processor adjusts the initial compression parameters when the image quality of the primary image data satisfies the predetermined standard, and determines whether the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard, and if the image quality of the secondary image data does not satisfy the predetermined standard, determines the initial compression parameters as optimal compression parameters, and the adjusted compression parameters can have a higher compression rate than the initial compression parameters.

[0033] In the computing device according to the present invention, the processor adjusts the initial compression parameters if the image quality of the primary image data does not satisfy the predetermined standard, and determines whether the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard, and if the image quality of the secondary image data satisfies the predetermined standard, determines the adjusted compression parameters as optimal compression parameters, and the adjusted compression parameters can have a lower compression rate than the initial compression parameters.

[0034] In a computing device according to the present invention, whether the image quality of the primary image data satisfies a predetermined standard can be determined based on whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold.

[0035] In a computing device according to the present invention, an image of the image data in the first format and an image of the primary image data in the second format are divided into tiles of a predetermined size, and a determination can be made for each tile as to whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold.

[0036] In the computing device according to the present invention, an analysis target in an image of the image data in the first format and an image of the primary image data in the second format are specified using a window of a predetermined size, and a determination of whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold can be made by moving the window a predetermined amount.

[0037] In the computing device according to the present invention, the processor receives image data in the first format from a terminal as data to be saved, receives an input from the terminal requesting transmission of the data to be saved, determines whether the terminal supports the second format, and if the terminal supports the second format, transmits final image data in the second format.

[0038] In the computing device according to the present invention, the processor receives image data in the first format from a terminal as data to be saved, receives an input from the terminal requesting transmission of the data to be saved, determines whether the terminal supports the second format, and if the terminal does not support the second format, transcodes the final image data in the second format into restored image data in the first format, and then transmits the restored image data in the first format.

[0039] In the computing device according to the present invention, the final image data in the second format includes restoration information for the image data in the first format, and the restoration information for the image data in the first format can be used when transcoding the image data in the second format into restored image data in the first format.

[0040] In the computing device according to the present invention, the restoration information of the image data in the first format may include at least one of information regarding a quantization matrix of the first format, information regarding the size of the image in the first format, and SAR (Sample Aspect Ratio) information of the first format.

[0041] A computer program stored on a computer-readable recording medium according to another aspect of the present invention may be a computer program for executing the image storage service providing method according to the present invention on a computer. <Details of the Invention> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein.

[0042] In describing the embodiments of the present disclosure, if it is determined that a specific description of a known configuration or function may obscure the gist of the present disclosure, the detailed description thereof will be omitted. In addition, in the drawings, parts that are not related to the description of the present disclosure will be omitted, and similar parts will be designated by similar reference numerals.

[0043] In this disclosure, when a component is referred to as being "coupled," "coupled," or "connected" to another component, this includes not only a direct connection, but also an indirect connection where another component is interposed between them. Furthermore, when a component is referred to as "including" or "having" another component, this does not mean that the other component is excluded, but that the other component can further be included, unless otherwise specified.

[0044] In this disclosure, terms such as "first" and "second" are used only to distinguish one component from another component, and do not limit the order or importance of the components unless otherwise specified. Therefore, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0045] In this disclosure, components that are distinguished from one another are used to clearly describe the characteristics of each component and do not necessarily mean that the components are separate. In other words, multiple components may be integrated into a single hardware or software unit, or a single component may be distributed into multiple hardware or software units. Therefore, unless otherwise specified, such integrated or distributed embodiments are also included within the scope of this disclosure.

[0046] In this disclosure, the components described in various embodiments are not necessarily essential components, and some of them may be optional components. Therefore, an embodiment consisting of a subset of the components described in one embodiment is also within the scope of this disclosure. Furthermore, an embodiment including other components in addition to the components described in various embodiments is also within the scope of this disclosure.

[0047] In addition, in this specification, the term "network" may be a concept that includes both wired and wireless networks. In this case, the term "network" may refer to a communication network through which data is exchanged between devices and systems, and between devices, and is not limited to a specific network.

[0048] In addition, in this specification, the term "device" may include not only mobile devices such as smartphones, tablet PCs, wearable devices, and HMDs (Head Mounted Displays), but also fixed devices such as PCs and home appliances with display capabilities. For example, the term "device" may be a computing device operable on a server, a vehicle, or an IoT (Internet of Things) device. In other words, in this specification, the term "device" may refer to equipment capable of performing the image storage service providing method according to the present invention, and is not limited to a specific type.

[0049] System and device configuration FIG. 1 is a diagram showing an example of a system in which an image storage service according to an embodiment of the present invention is performed.

[0050] The image storage service according to the present invention may be implemented in a system including one or more user devices 101 , 102 , 103 and a server 110 connected via a network 104 .

[0051] Each of the user devices 101, 102, 103 may also be referred to as a client, terminal, or user terminal, and can connect to a server 110 via a network 104 to send and receive data to and from other user devices or servers. The user devices and / or servers may be implemented as computing devices.

[0052] A client module for using the image storage service can be installed in each of the user devices 101, 102, and 103. Also, a server module for providing the image storage service can be installed in the server 110.

[0053] A user who uses the image storage service can connect to the server 110 that provides the service by inputting (or transmitting) predetermined connection information (ID and password) via a user device. The server 110 can identify the connected user using the connection method inputted (or transmitted) from the user device. The server 110 can also collect, accumulate, store, and query information about the identified user, or support data transmission and reception between identified users.

[0054] FIG. 2 is a block diagram showing an example of the configuration of a user device that uses the image storage service according to the present invention and a server that provides the image storage service according to the present invention.

[0055] 2(a), the user device 200 may include a processor 210, a memory 220, a transceiver 230, an input unit 240, and an output unit 250. The user device 200 may further include other components related to the operation and functions of the device and is not limited to the above-described embodiment. For example, the user device 200 may further include an imaging unit (not shown) for acquiring image data.

[0056] In this disclosure, image data may refer to coded data or a bitstream obtained by coding an image. Alternatively, image data may refer to the image itself. Image data may be stored or transmitted in the form of coded data or a bitstream. Image data may be output in the form of a restored image by decoding the coded data or bitstream. Comparison or verification of image quality may be performed on the image restored by decoding the coded data or bitstream.

[0057] In addition, in the present disclosure, an image can include not only a still image but also a moving image composed of multiple still images. Also, an image can include not only a progressive scanning image but also an interlaced scanning image.

[0058] The processor 210 may control the operations of other components within the user device 200. For example, the processor 210 may process information acquired via the input unit 240, the transceiver unit 230, and the image capture unit. The processor 210 may also read and process information stored in the memory 220. The processor 210 may output the processed information via the output unit 250, store it in the memory 220, or transmit it to the outside via the transceiver unit 230.

[0059] For example, the processor 210 can receive image data via the input unit 240 or the transceiver unit 230, acquire the image data via the imaging unit, or read the image data from the memory 220. The processor 210 can also store the image data in the memory 220, transmit the image data to the outside via the transceiver unit 230, or output the image data via the output unit 250. For example, to use the image storage service according to the present disclosure, the processor 210 can transmit the image data to the server 260 via the transceiver unit 230.

[0060] For example, when a user request is received via the input unit 240, the processor 210 may control the operations of other components to process the user request. For example, to use the image storage service according to the present disclosure, a user may request specific image data via the input unit 240. The processor 210 may receive the request and transmit information about the requested specific image data and / or information about the user device to the server 260 via the transceiver unit 230. Furthermore, when the processor 210 receives the requested specific image data from the server 260, it may store the image data in the memory 220, output the image data via the output unit 250, or transmit the image data to an external device via the transceiver unit 230. The information about the specific image data may include information that can identify the image data. The information about the user device may include information about functions supported by the user device (e.g., a function for playing images in a specific format).

[0061] The memory 220 can store information acquired from outside the user device, such as information received from the server 110 or another user device via the transceiver 230, information acquired via the input unit 240 of the user device, or information acquired via a photographing unit of the user device. The memory 220 can also store information generated within the user device 200. For example, the memory 220 can include a database. The memory 220 can include all types of storage media capable of storing data. In the present disclosure, the memory 220 may also be referred to as storage.

[0062] The transceiver 230 can exchange data with the server 110 or other user devices via a network. The transceiver 230 can include any type of wired and / or wireless communication module that can communicate with the outside world.

[0063] The input unit 240 may include input means implemented by various sensors, mechanical buttons, etc. provided in the user device 200. The user device 200 may include, for example, input means using a pressure sensor, an electrostatic touch sensor, etc. (e.g., a virtual keyboard displayed on a touch screen), mechanical buttons, etc. as the input unit 240. The user device 200 may acquire information sensed by the sensors or input from the mechanical buttons as input information.

[0064] The output unit 250 can output to the outside information acquired or received by the user device 200, information processed by the user device 200, etc. The output unit 250 can include, for example, a display that outputs visual information.

[0065] The image capturing unit may include any type of image capturing means capable of capturing still or moving images, for example, the image capturing unit may be a camera module provided in a smartphone.

[0066] 2(b), the server 260 may include a processor 280, a memory 270, and a transceiver 290. The server 260 may further include other components related to the operation of the server or system, and is not limited to the above-described embodiments.

[0067] The processor 280 may control the operations of other components within the server 260. For example, the processor 280 may process information acquired via the transceiver 290. The processor 280 may also read and process information stored in the memory 270. The processor 280 may store the processed information in the memory 270 or transmit it to the outside via the transceiver 290.

[0068] The processor 280 can execute the method for providing an image storage service according to the present disclosure. Specifically, the processor 280 can store image data received from a user device via the transceiver 290 in the memory 270 to provide the image storage service according to the present disclosure. The processor 280 can also read the image data stored in the memory 270 based on a predetermined criterion, transcode the read image data, and store the transcoded image data in the memory 270. The processor 280 can compare the image quality of the image data read from the memory 270 with that of the transcoded image data. If the result of the image quality comparison satisfies the predetermined criterion, the processor 280 can store the transcoded image data in the memory 270. In this case, the image data read from the memory 270 can be deleted from the memory 270. In the present disclosure, the memory 270 may also be referred to as a storage.

[0069] Furthermore, the processor 280 can receive a request for specific image data and / or information about the user device from the user device via the transceiver 290, and can read the specific image data from the memory 270. The processor 280 can transmit the read specific image data to the user device via the transceiver 290. In this case, the processor 280 can transcode the read specific image data based on the information about the user device, and then transmit the transcoded specific image data.

[0070] The memory 270 can store information received from the outside via the transceiver 290. The memory 270 can also store information generated within the server 260. For example, image data transcoded according to the image storage service providing method according to the present invention can be stored in the memory 270. For example, the memory 270 can include a database. The memory 270 can include all types of storage media capable of storing data. In the present disclosure, the memory 270 may also be referred to as storage.

[0071] The transceiver 290 can exchange data with user devices or other servers connected to the network, and can include any type of wired and / or wireless communication module that can communicate with the outside world.

[0072] The user device and / or server of the present disclosure may be an example of a computing apparatus or computing device.

[0073] Transcoding To implement the image storage service providing method according to the present invention, image data may be transcoded, for example, image data in a first format may be transcoded into image data in a second format.

[0074] In this disclosure, a format may refer to an image compression format. That is, it may refer to a compression method used to compress an image. A first format and a second format may refer to different compression methods. Furthermore, transcoding may refer to converting image data compressed in a first format into a second format and compressing it. Transcoding may be performed by decoding image data in the first format to restore the image, and compressing the restored image using another compression method to generate image data in the second format. Here, a compression method may refer to a codec.

[0075] In the present disclosure, first format data may refer to data in a first format or image data in a first format, and second format data may refer to data in a second format or image data in a second format.

[0076] For example, the first format may refer to a form in which an image is compressed using a codec with relatively low compression efficiency, and the second format may refer to a form in which an image is compressed using a codec with relatively high compression efficiency, and therefore the amount of image data in the first format for the same image may be greater than the amount of image data in the second format.

[0077] FIG. 3 is a diagram illustrating a transcoding method according to an embodiment of the present invention.

[0078] The transcoding method of FIG. 3 can be performed, for example, by the processor 280 of the server 260 that executes the image storage service providing method according to the present invention.

[0079] A transcoding method according to one embodiment of the present invention may include a step of selecting image data in a first format (S310), a step of determining initial compression parameters (S320), a step of searching for optimal compression parameters (S330), and / or a step of storing image data in a second format (S340).

[0080] According to the transcoding method of the present invention, image data in a first format to be transcoded can be selected (S310).

[0081] The image data in the first format to be transcoded can be selected in various ways. For example, image data in the first format received from an external device via a transceiver can be selected as the data to be transcoded. Alternatively, image data in the first format read from a memory can be selected as the data to be transcoded. Alternatively, any one of one or more pieces of image data in the first format stored in a memory can be selected as the data to be transcoded.

[0082] For example, a user can transmit (upload) acquired image data in a first format to a server. The transmitted image data in the first format can be stored in the server's memory as first format data. One or more pieces of first format data (e.g., image data in the first format) can be stored in the server's memory. A user can receive transmission of specific image data from the server's memory by requesting the server to transmit the specific image data.

[0083] A statistical analysis of inputs from users requesting image data stored on a server revealed that after a user uploads image data to the server, there are frequent requests for the image data within a certain period of time, but after the certain period, there is a tendency for the number of requests for the image data to decrease sharply.

[0084] When image data in the first format to be transcoded is selected from memory, the statistical analysis results described above are taken into consideration. That is, image data in the first format that has been stored in memory for a predetermined period of time or longer can be selected as the target for transcoding. By transcoding image data in the first format that is expected to be requested less frequently by users into image data in the second format, which has higher compression efficiency, the amount of image data is reduced, thereby enabling more efficient use of server memory. Furthermore, image data in the first format that is expected to be requested more frequently by users can be stored as is without transcoding, allowing for faster response to user requests.

[0085] When image data in the first format to be transcoded is selected, initial compression parameters for transcoding the selected image data in the first format into the second format can be determined (S320).

[0086] Since transcoding converts image data in a first format into image data in a second format, in the description of FIG. 3 , the compression parameters may be parameters for performing compression using a compression method for the second format. For example, the compression parameters may be parameters related to the compression ratio or the image quality of the compressed image. For example, the compression parameters may be parameters related to quantization. As an example, the quantization parameters may be a quantization matrix, a quantization step size, etc. The quantization parameters may affect the compression ratio and the image quality of the compressed image. For example, if the quantization step size is large, the compression ratio will be high but the image quality of the compressed image will be low. Conversely, if the quantization step size is small, the compression ratio will be low but the image quality of the compressed image will be high. In other words, the compression parameters may include an image quality factor.

[0087] The image data in the second format generated by transcoding can be stored in memory in place of the image data in the first format. Therefore, the image quality of the image data in the second format is required to be the same as that of the image data in the first format, or at least similar enough that a user cannot perceive a difference in the image quality of the two image data. In other words, the image quality of the image data in the second format is required to meet a predetermined standard. Furthermore, from the perspective of efficient use of server storage space, it is preferable to minimize the amount of image data in the second format.

[0088] Compression parameters that satisfy both of these requirements can be determined in an optimal compression parameter search step (S330). As will be described later, the optimal compression parameter search step involves iteratively adjusting compression parameters while performing transcoding. Therefore, by appropriately selecting initial compression parameters, the number of iterations of the process can be reduced.

[0089] The initial compression parameters may be determined based on statistics of one or more previously used compression parameters. For example, the initial compression parameters may be determined using at least one of the maximum value, minimum value, median value, average value, weighted average value, and mode value of N previously used compression parameters. In this case, the N compression parameters may be N initial compression parameters or N optimal compression parameters. N may be an integer greater than or equal to 1. Alternatively, the optimal compression parameters most recently used may be determined as the initial compression parameters.

[0090] Another embodiment for determining initial compression parameters may use information about image data in a first format (e.g., attribute information) and information about the relationship between optimal compression parameters for the image data (hereinafter referred to as "relationship information"). For example, once optimal compression parameters for image data in a first format are found, relationship information about the relationship between the information about the image data in the first format and the optimal compression parameters may be stored or learned. The relationship information may be cumulatively stored or learned. The learning may refer to learning using machine learning. Subsequently, once image data in the first format to be transcoded is selected, initial compression parameters may be determined based on information about the selected image data in the first format and the relationship information. For example, existing transcoded image data in the first format having similar attributes to the selected image data in the first format to be transcoded may be determined, and the optimal compression parameters applied to the existing image data may be determined as initial compression parameters for the current image data. Alternatively, information about the current image data may be input into a machine learning-based learning model to determine the initial compression parameters.

[0091] Once the initial compression parameters have been determined, an optimal compression parameter search process can be performed using the initial compression parameters (S330). As described above, the optimal compression parameters may refer to compression parameters for generating image data in the second format that has the smallest amount of data while satisfying the required image quality. The optimal compression parameter search process will be described in detail below with reference to Figures 4 to 6.

[0092] Once the optimal compression parameters have been determined, the image data in the second format transcoded using the optimal compression parameters can be stored (S340). For example, the image data in the second format can replace the image data in the first format. That is, the image data in the first format can be permanently deleted from the server's memory and the image data in the second format can be stored in memory instead.

[0093] In this specification, image data in a second format obtained by transcoding image data in a first format based on initial compression parameters may be referred to as primary image data in the second format. Image data in a second format obtained by transcoding image data in a first format based on adjusted compression parameters may be referred to as secondary image data in the second format. Image data in a second format obtained by transcoding image data in a first format based on optimal compression parameters may be referred to as final image data in the second format.

[0094] As will be described later, the image data in the second format can be transcoded back into image data in the first format. This transcoding can be performed by decoding the image data in the second format to restore the image, and then compressing the restored image using the compression method of the first format. In this case, the image data in the first format generated by transcoding the image data in the second format must be as similar as possible to the original image data in the first format selected in step S310. Therefore, restoration information related to the restoration of the image data in the first format must be stored in advance.

[0095] FIG. 7 is a diagram showing an example of storing restoration information for image data in the first format.

[0096] In the example shown in FIG. 7, JPEG refers to the compression method of the first format, and HEIF refers to the compression method of the second format.

[0097] By using the transcoding method according to the present disclosure, image data in JPEG format can be transcoded into image data in HEIF format, after which the image data in JPEG format can be permanently deleted from memory.

[0098] In the example shown in Figure 7, the image data in JPEG format may include a header (JPEG headers), metadata (Image meta), and actual image data (Scan data). The header and / or metadata may include information about the image and / or information necessary for decoding the image. For example, the header and / or metadata may include a quality factor. In addition, the header and / or metadata may include information about the size of the image (width, height), a sample aspect ratio (SAR), etc.

[0099] In the example shown in Figure 7, image data in the HEIF format may include a header (MP4 meta), image metadata (Image meta data), and actual image data (HEVC data). According to the present disclosure, restoration information for image data in a first format may be included and stored in image data in a second format. For example, when decoding image data in the second format, the restoration information may be included in an area not referenced by a decoder. For example, the area including the restoration information may be represented by a comment header or a custom header of the image data in the second format.

[0100] 7, a quality factor of the JPEG format is stored in the image data of the HEIF format as the restoration information, but the restoration information is not limited thereto and may include information stored in the header and / or metadata of the JPEG format, such as information about the image size, sample aspect ratio, etc.

[0101] Step S340 is a step of storing the image data in the second format, and at this time, the restoration information may be stored together as part of the image data in the second format. Specific use of the stored restoration information will be described later with reference to FIG. 8.

[0102] Searching for optimal compression parameters FIG. 4 is a diagram for explaining an example of a search process for the optimum compression parameters.

[0103] The example shown in FIG. 4 is an example in which the image quality of the image data in the second format transcoded based on the initial compression parameters satisfies a predetermined standard.

[0104] The search process of Figure 4 may begin with initial compression parameters, i.e., image data in a first format may be transcoded into image data in a second format based on the initial compression parameters (S410).

[0105] It is then determined whether the image quality of the second-format image data generated by transcoding satisfies a predetermined standard (S420). For example, if the difference in image quality between the first-format image data and the second-format image data is equal to or less than a predetermined threshold, it can be determined that the predetermined standard is satisfied. A method for determining whether the image quality satisfies the predetermined standard will be described later with reference to FIG. 6.

[0106] 4, the image quality of the second-format image data transcoded based on the initial compression parameters satisfies a predetermined standard, so the initial compression parameters may be adjusted (S430). For example, the compression parameters may be adjusted to increase the compression ratio.

[0107] The above process can then be repeated based on the adjusted compression parameters, and if in step S420 the image quality of the transcoded second format image data does not meet the predetermined criteria, the process can proceed to step S440.

[0108] In step S440, the compression parameters immediately preceding the current compression parameters can be determined as optimal compression parameters. The current compression parameters cannot be optimal compression parameters because they do not satisfy the predetermined criteria for image quality. The immediately preceding compression parameters (compression parameters before adjustment) that have the highest compression ratio while satisfying the predetermined criteria for image quality can be determined as optimal compression parameters.

[0109] FIG. 5 is a diagram for explaining another example of the search process for the optimum compression parameter.

[0110] The example shown in FIG. 5 is a case where the image quality of the image data in the second format transcoded based on the initial compression parameters does not satisfy a predetermined standard.

[0111] The search process of Figure 5 may begin with initial compression parameters, i.e., image data in a first format may be transcoded into image data in a second format based on the initial compression parameters (S510).

[0112] It is then determined whether the image quality of the second-format image data generated by transcoding satisfies a predetermined standard (S520). For example, if the difference in image quality between the first-format image data and the second-format image data is equal to or less than a predetermined threshold, it can be determined that the predetermined standard is satisfied. A method for determining whether the image quality satisfies the predetermined standard will be described later with reference to FIG. 6.

[0113] 5, the image quality of the image data in the second format transcoded based on the initial compression parameters does not meet a predetermined standard, so the initial compression parameters may be adjusted (S530). For example, the compression parameters may be adjusted to reduce the compression ratio.

[0114] The above process can then be repeated based on the adjusted compression parameters, and if the image quality of the transcoded second format image data meets a predetermined standard in step S520, the process can proceed to step S540.

[0115] In step S540, the current compression parameters may be determined as the optimal compression parameters.

[0116] In the manner described above, it is possible to search for the optimum compression parameters that provide the highest compression ratio while satisfying a predetermined standard regarding image quality.

[0117] The adjustment range of the compression parameters may be determined in the same manner as the initial compression parameters. For example, the adjustment range of the compression parameters may be determined based on statistics of one or more previously used adjustment ranges. Alternatively, the adjustment range may be determined based on information relating to the relationship between information (e.g., attribute information) about the image data in the first format and the adjustment range.

[0118] Alternatively, the adjustment range of the compression parameter can be determined based on the difference in image quality between the image data in the first format and the transcoded image data in the second format. For example, if the difference is small, the adjustment range can be determined to be small, and if the difference is large, the adjustment range can be determined to be large.

[0119] To determine the adjustment range of the compression parameters, one or more of the above methods may be combined and applied.

[0120] 4 and 5, the compression parameters are adjusted in only one direction (to increase the compression ratio or decrease the compression ratio), but this is not limiting, and the compression parameters may be adjusted in both directions.

[0121] For example, in the embodiment described with reference to FIG. 4, if the first compression parameter satisfies the criteria of step S420, but the second compression parameter obtained by adjusting the first compression parameter does not satisfy the criteria of step S420, it can be checked whether the third compression parameter obtained by adjusting the second compression parameter satisfies the criteria of step S420.

[0122] Similarly, in the embodiment described with reference to FIG. 5, if the first compression parameters do not satisfy the criteria of step S520, but the second compression parameters obtained by adjusting the first compression parameters satisfy the criteria of step S520, it can be checked whether the third compression parameters obtained by adjusting the second compression parameters satisfy the criteria of step S520.

[0123] In the above-described modification in which the compression parameters are adjusted in both directions, the compression ratio of the third compression parameter may be between the compression ratios of the first and second compression parameters. By adjusting the compression parameters in both directions as described above, the optimal compression parameters can be determined. In this case, the number of compression parameter adjustments can be predetermined. Additionally or alternatively, the optimal compression parameters can be searched for using both the search process of FIG. 4 and the search process of FIG. 5 together.

[0124] Image quality comparison FIG. 6 is a diagram for explaining an example of a method for comparing the image quality of image data in the first format with the image quality of image data in the second format.

[0125] The comparison of the image quality of two image data can be performed by decoding the two image data and comparing the image quality of the two restored images. The comparison of the image quality can be performed using commonly used image quality comparison matrices, such as PSNR (Peak Signal to Noise Ratio) and / or SSIM (Structural Similarity). However, the comparison is not limited to the above examples, and any of a variety of methods for comparing the image quality can be used.

[0126] 6(a) may be a first image restored by decoding image data in a first format, and FIG. 6(b) may be a second image restored by decoding image data in a second format. The comparison between the first and second images may be performed on an image-by-image basis. That is, the comparison may be performed based on whether a comparison result value (a difference value indicating the difference in image quality between the two images) derived by performing an image quality comparison between the first and second images is equal to or less than a predetermined threshold. If the difference value is equal to or less than the predetermined threshold, it may be determined that the image quality of the image data in the second format transcoded in step S420 or step S520 meets the predetermined standard. Otherwise, it may be determined that the image quality of the image data in the second format transcoded does not meet the predetermined standard.

[0127] For example, if PSNR and / or SSIM are performed on the entire image, the values derived by PSNR and / or SSIM may be average values for the entire image. Therefore, in this case, accurate image quality comparison may not be performed. An image may contain simple regions with little image information and complex regions with a lot of image information. For example, in FIG. 6, the upper left corner of the image may be a simple region with no edges, while the middle region of the image may be a complex region with many edges. In this case, even if the difference value between the image quality of two images in the complex region is greater than a predetermined threshold, the difference value between the image quality of the two images in the simple region is almost the same. Therefore, in step S420 of FIG. 4, the average difference value for the entire image may be determined to be equal to or less than the predetermined threshold. In other words, even if the image as a whole meets the predetermined image quality standard, some parts may not meet the predetermined image quality standard. Therefore, image quality comparison performed on the entire image as a single unit may not be desirable.

[0128] In the example shown in FIG. 6, an image can be divided into tiles of a predetermined size. Furthermore, image quality comparison can be performed on a tile-by-tile basis. Specifically, image tiles of a first-format image and corresponding tiles of a second-format image can be compared for image quality using PSNR and / or SSIM. Image quality comparison for each tile can be performed for all tiles constituting an image. If a predetermined image quality standard is met for all tiles, it can be determined that the image quality of the transcoded second-format image data meets the predetermined standard. In other words, if even one tile does not meet the predetermined image quality standard, it can be determined that the image quality of the second-format image data does not meet the predetermined standard. In this way, by comparing image quality for each tile constituting an image, the image quality of the second-format image data can be guaranteed.

[0129] In another embodiment, N tiles may be selected from the tiles obtained by dividing the image in order of increasing complexity, and image quality comparison may be performed for only the selected N tiles. This is because if the image quality comparison result for a relatively high complexity region meets a predetermined standard, the image quality comparison result for a relatively low complexity region is also likely to meet the predetermined standard. In this case, N may be an integer greater than or equal to 1. The size of the tiles used to divide the image may be predefined or adaptively determined based on information about the image. For example, if the image size is large, the predetermined size may be determined to be relatively large. For example, if the image contains many simple regions, the predetermined size may be determined to be relatively large.

[0130] Alternatively, an image can be divided into tiles of different sizes, for example, simple regions in the image can be divided into large-sized tiles and complex regions can be divided into small-sized tiles.

[0131] The shape of the tiles into which the image is divided may be an M×N rectangle, where M and N may be the same or different positive integers.

[0132] The method of dividing an image is not limited to the above example. For example, simple regions and complex regions can be extracted from an image based on the edges of objects contained in the image. The image quality comparison can be performed separately for the simple regions and the complex regions. Alternatively, if the image quality comparison result for the complex regions meets a predetermined criterion, the image quality comparison result for the simple regions is likely to also meet the predetermined criterion, so the image quality comparison can be performed only for the complex regions. Alternatively, the complex regions can be further subdivided according to complexity. In this case, the image quality comparison can be performed only for N complex regions in descending order of complexity. In this case, N can be an integer greater than or equal to 1.

[0133] In another embodiment, the image quality of image data in the first format and the image quality of image data in the second format can be compared using a sliding window method, i.e., a window that specifies an analysis target within the image can be moved by any amount to compare the image quality of the corresponding portions of the image data in the first format and the image data in the second format.

[0134] In this case, the size of the window specifying the analysis target can be defined in advance. It can also be adaptively determined based on information about the image of the first-format image data. For example, if the image size is large, the window size can be determined to be relatively large. For example, if the image contains many simple regions, the window size can be determined to be relatively large.

[0135] The amount of window movement can also be predefined or adaptively determined based on information about the image, for example, the amount of movement can be larger in simple regions than in complex regions of the image.

[0136] The size of the window may be equal to or smaller than the size of the image, and the shape of the window may be an MxN rectangle, where M and N may be the same or different positive integers.

[0137] Provision of stored image data FIG. 8 is a diagram illustrating an embodiment in which image data stored in a memory is provided in response to a request from a user device.

[0138] A computing device (e.g., a server) performing the image storage service providing method according to the present invention may receive image data from a user terminal and store the received image data in a memory as data to be stored, where the image data may be image data in a first format.

[0139] Furthermore, the computing device according to the present invention can receive a user input from a terminal requesting transmission of image data stored in the memory. The server can provide an image storage service by transmitting the requested image data to the user. The user request can include information about the specific image data and / or information about the user device. The information about the user device can include information about functions supported by the user device. For example, the information about the user device can include information about whether the image data in the second format can be restored.

[0140] Specific image data requested for transmission from a user terminal may be stored in memory as image data in a first format, or may be transcoded into image data in a second format and stored in memory after a predetermined period of time has elapsed. If the specific image data requested by the user is stored as image data in the first format, the server can provide an image storage service by transmitting the image data in the first format to the user device. In the following, it is assumed that the specific image data requested by the user is transcoded into image data in the second format and stored.

[0141] When a user input requesting transmission of image data in a second format is received (S810), it is possible to determine whether the user device can decompress the image data in the second format, i.e., whether the user device supports the compression method of the second format, based on information about the user device (S820).

[0142] If the user device supports the compression method of the second format, the image data in the second format is read from the memory and transmitted to the user device (S850), thereby providing an image storage service.

[0143] If the user device does not support the compression method of the second format, the image data in the second format may be transcoded to image data in the first format (S830). The image data in the first format obtained in step S830 may be different from the image data in the first format originally received from the user terminal. Therefore, the image data in the first format obtained in step S830 may also be referred to as restored image data in the first format.

[0144] The compression parameters for the transcoding can be derived based on the embodiments described with reference to FIGS. 3 to 5. Alternatively, as described with reference to FIG. 7, the transcoding can be performed using restoration information for the first-format image data stored in the second-format image data. The restoration information can include a quality factor for the first-format image data, information about the size of the first-format image, and / or a sample aspect ratio. By performing transcoding using pre-stored restoration information in this manner, transcoding can be performed without comparing image quality. By using the quality factor for the first-format image data, the quality of the transcoded first-format image can be approximately the same as the quality of the initial original image uploaded to the server by the user. Furthermore, by using the size and / or sample aspect ratio of the first-format image, the size of the transcoded first-format image can be made the same as that of the original image. This can prevent unnecessary network traffic and avoid a situation in which an image with a different size or shape from the original image is provided to the user.

[0145] The server can provide an image storage service by transmitting the image data in the first format obtained by transcoding to the user device (S840).

[0146] According to the embodiment described with reference to FIG. 8, if the user device does not support the compression method of the second format, image data in the second format is transcoded to image data in the first format and then transmitted. However, without being limited thereto, if the user device supports the compression method of the third format, image data in the second format can also be transcoded to image data in the third format and then transmitted. In this case, compression parameters required for transcoding to the third format can be derived based on the embodiments described with reference to FIGS. 3 to 5. Alternatively, part of the restoration information stored in the image data in the second format can be used. For example, the size and / or sample aspect ratio of the image in the first format can be used regardless of the format of the image to be transcoded. If the compression rate of the compression method of the third format is higher than that of the compression method of the first format, the amount of image data transcoded using the compression method of the third format is smaller than the amount of image data transcoded using the compression method of the first format, thereby minimizing network traffic.

[0147] According to the image storage service providing method disclosed herein, a user can receive images from a server that are almost identical in image quality to the image originally uploaded. Furthermore, image data is transcoded and stored using a highly efficient compression method, allowing for efficient use of server storage space. For example, the compression rate of the HEIF format is more than twice that of the JPEG format, so according to the present invention, the space required to store image data of the same image can be reduced by 50% or less.

[0148] Although the exemplary methods of the present disclosure are expressed as a series of operations for clarity of explanation, this is not intended to limit the order in which the steps are performed, and the steps may be performed simultaneously or in a different order if necessary. To achieve a method according to the present disclosure, other steps may be included in addition to the steps shown, or some steps may be omitted and the remaining steps may be included, or some steps may be omitted and additional other steps may be included.

[0149] The various embodiments of the present disclosure are not intended to enumerate all possible combinations, but are intended to describe representative aspects of the present disclosure, and the matters described in the various embodiments may be applied independently or in combination of two or more.

[0150] Furthermore, methods according to an embodiment of the present invention can be embodied in the form of program instructions executable by various computer devices and recorded on a computer-readable recording medium. The computer-readable recording medium can include, alone or in combination, program instructions, data files, data structures, and the like. The program instructions recorded on the medium may be those specially designed and constructed for the present invention, or those known and available to those of ordinary 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 and DVDs; magneto-optical media such as floptical disks; and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include not only machine language code produced by a compiler, but also high-level language code executable by a computer using an interpreter, etc. The hardware devices can be configured to operate as one or more software modules to perform the operations of the present invention, or vice versa.

[0151] Additionally, various embodiments of the present disclosure may be implemented using hardware, firmware, software, or a combination thereof, etc. In the case of a hardware implementation, the implementation may be using one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), general processors, controllers, microcontrollers, microprocessors, etc.

[0152] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause operations according to the methods of the various embodiments to be performed on a device or computer device, and non-transitory computer-readable media on which such software or instructions, etc., are stored and executable on a device or computer.

Claims

1. 1. A method for providing an image storage service performed by a computing device including at least one processor and a memory, comprising: selecting image data in a first format; determining initial compression parameters for converting the selected image data in a first format to a second format; a step of searching for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether or not image quality of the primary image data satisfies a predetermined standard; and storing final image data in a second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters in the memory; The step of searching for optimal compression parameters comprises: adjusting the initial compression parameters if the image quality of the primary image data satisfies the predetermined standard; a step of determining whether or not the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard; and if the image quality of the secondary image data does not satisfy the predetermined standard, determining the initial compression parameters as optimal compression parameters; The adjusted compression parameters have a higher compression ratio than the initial compression parameters.

2. The step of selecting image data in the first format includes:

2. The image storage service providing method according to claim 1, further comprising the step of selecting, as the image data in the first format, one of at least one first-format data that has been stored in the memory for a predetermined period of time or more.

3. The image storage service providing method of claim 1 , wherein the initial compression parameters are determined based on statistics of one or more compression parameters used in previous transcoding.

4. The step of searching for optimal compression parameters comprises: If the image quality of the primary image data does not satisfy the predetermined standard, adjusting the initial compression parameters; a step of determining whether or not the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard; determining the adjusted compression parameters as optimal compression parameters if the image quality of the secondary image data satisfies the predetermined standard; The image storage service providing method according to claim 1 , wherein the adjusted compression parameters have a compression ratio lower than that of the initial compression parameters.

5. Whether the image quality of the primary image data satisfies a predetermined standard or not is determined by: The image storage service providing method according to claim 1, wherein the determination is based on whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is less than or equal to a predetermined threshold value.

6. the image of the image data in the first format and the image of the primary image data in the second format are divided into tiles of a predetermined size; 6. The image storage service providing method according to claim 5, wherein a determination is made for each tile as to whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold value.

7. An analysis target is specified in the image of the image data of the first format and the image of the primary image data of the second format using a window of a predetermined size; 6. The image storage service providing method according to claim 5, wherein the determination of whether a value related to the difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is below a predetermined threshold value is performed while moving the window by a predetermined amount.

8. receiving image data in the first format from a terminal as data to be saved; receiving an input from the terminal requesting transmission of the data to be saved; determining whether the terminal supports the second format; The image storage service providing method of claim 1 , further comprising: if the terminal supports the second format, transmitting the final image data in the second format.

9. receiving image data in the first format from a terminal as data to be saved; receiving an input from the terminal requesting transmission of the data to be saved; determining whether the terminal supports a second format; 2. The image storage service providing method of claim 1, further comprising the step of: if the terminal does not support the second format, transcoding the final image data in the second format into restored image data in the first format, and then transmitting the restored image data in the first format.

10. The final image data in the second format is containing restoration information for the image data in the first format; 10. The image storage service providing method according to claim 9, wherein restoration information of the image data in the first format is used when transcoding the final image data in the second format into restored image data in the first format.

11. The restoration information of the image data in the first format is 11. The image storage service providing method of claim 10, further comprising: information on a quantization matrix of the first format; information on a size of the image of the first format; and information on a sample aspect ratio (SAR) of the first format.

12. A computer program stored on a computer-readable recording medium for executing an image storage service providing method on a computer, The method comprises: selecting image data in a first format; determining initial compression parameters for converting the selected image data in a first format to a second format; a step of searching for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether or not image quality of the primary image data satisfies a predetermined standard; and storing final image data in a second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters in a memory; The step of searching for optimal compression parameters comprises: adjusting the initial compression parameters if the image quality of the primary image data satisfies the predetermined standard; a step of determining whether or not the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard; and if the image quality of the secondary image data does not satisfy the predetermined standard, determining the initial compression parameters as optimal compression parameters; The adjusted compression parameters have a higher compression ratio than the initial compression parameters.

13. A computing device including at least one processor and a memory, The processor: Selecting image data in a first format; determining initial compression parameters for converting the selected image data in the first format into a second format; searching for optimal compression parameters for primary image data in a second format obtained by transcoding the selected image data in the first format based on the initial compression parameters, based on whether or not the image quality of the primary image data satisfies a predetermined standard; storing final image data in a second format obtained by transcoding the selected image data in the first format based on the optimal compression parameters in the memory; The processor: If the image quality of the primary image data satisfies the predetermined standard, adjust the initial compression parameters, and determine whether the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard, and if the image quality of the secondary image data does not satisfy the predetermined standard, determine the initial compression parameters as optimal compression parameters; The adjusted compression parameters have a higher compression ratio than the initial compression parameters.

14. The processor: If the image quality of the primary image data does not satisfy the predetermined standard, adjust the initial compression parameters, and determine whether the image quality of the secondary image data in a second format obtained by transcoding the image data in the first format based on the adjusted compression parameters satisfies the predetermined standard, and if the image quality of the secondary image data satisfies the predetermined standard, determine the adjusted compression parameters as optimal compression parameters; The computing device of claim 13 , wherein the adjusted compression parameters have a lower compression ratio than the initial compression parameters.

15. Whether the image quality of the primary image data satisfies a predetermined standard or not is determined by:

14. The computing device of claim 13, wherein the determination is based on whether a value related to a difference between image quality of the image data in the first format and image quality of the primary image data in the second format is less than or equal to a predetermined threshold.

16. the image of the image data in the first format and the image of the primary image data in the second format are divided into tiles of a predetermined size; 16. The computing device of claim 15, wherein determining whether a value related to a difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is less than or equal to a predetermined threshold is performed for each tile.

17. A window of a predetermined size is used to specify an analysis target in the image of the image data in the first format and the image of the primary image data in the second format; 16. The computing device of claim 15, wherein determining whether a value related to a difference between the image quality of the image data in the first format and the image quality of the primary image data in the second format is less than or equal to a predetermined threshold is performed while moving the window a predetermined amount.

18. The processor: receiving image data in the first format from a terminal as data to be saved; receiving an input from the terminal requesting transmission of the data to be saved; determining whether the terminal supports the second format; If the terminal supports the second format, transmitting final image data in the second format; 14. The computing device of claim 13, wherein if the terminal does not support the second format, the computing device transcodes the final image data in the second format into restored image data in a first format and then transmits the restored image data in the first format.

Images