阅读说明：本技术 深度图的获取方法、装置、电子设备及存储介质 (Method and device for acquiring depth map, electronic equipment and storage medium ) 是由 李东洋 化雪诚 王海彬 刘祺昌 户磊 于 2021-09-09 设计创作，主要内容包括：本发明实施例涉及图像处理技术领域,公开了一种深度图的获取方法、装置、电子设备及存储介质。深度图的获取方法,包括：获取红外背景图、参考散斑图案和所述红外背景图对应的场景深度信息；根据所述场景深度信息对所述参考散斑图案进行立体匹配,得到视差散斑图案；将所述视差散斑图案叠加到所述红外背景图,得到风格迁移散斑图上；将所述风格迁移散斑图转化为深度图。通过图像数据处理就能够得到新的深度图,不需要在实际场景中进行人工采集,避免了人力物力的浪费,节约了资源。(The embodiment of the invention relates to the technical field of image processing, and discloses a method and a device for acquiring a depth map, electronic equipment and a storage medium. The method for acquiring the depth map comprises the following steps: acquiring an infrared background image, a reference speckle pattern and scene depth information corresponding to the infrared background image; performing stereo matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern; superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern; and converting the style migration speckle pattern into a depth map. The new depth map can be obtained through image data processing, manual collection in an actual scene is not needed, waste of manpower and material resources is avoided, and resources are saved.)

1. A method for obtaining a depth map is characterized by comprising the following steps:

acquiring an infrared background image, a reference speckle pattern and scene depth information corresponding to the infrared background image;

performing stereo matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern;

superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern;

and converting the style migration speckle pattern into a depth map.

2. The method for acquiring the depth map according to claim 1, wherein the acquiring the infrared background map and the scene depth information corresponding to the infrared background map comprises:

obtaining a speckle pattern;

performing speckle extraction on the speckle pattern to obtain a scene speckle pattern;

carrying out image subtraction on the speckle pattern and the scene speckle pattern to obtain an initial infrared image;

carrying out dodging treatment on the initial infrared image to obtain the infrared background image;

and performing depth recovery on the scene speckle pattern to obtain the scene depth information.

3. The method for obtaining the depth map according to claim 2, wherein the performing speckle extraction on the speckle pattern to obtain a scene speckle pattern comprises:

carrying out image filtering processing on the speckle pattern;

performing background subtraction on the speckle pattern after the filtering processing;

and carrying out binarization and connected region detection on the speckle pattern after background subtraction to obtain the scene speckle pattern.

4. The method of claim 2, wherein the reference speckle pattern and the scene speckle pattern are different.

5. The method for acquiring the depth map according to any one of claims 1 to 4, wherein the acquiring the infrared background map and the scene depth information corresponding to the infrared background map includes:

and acquiring an infrared background image and the scene depth information corresponding to the infrared background image from a preset speckle data set.

6. The method for obtaining the depth map according to any one of claims 1 to 4, wherein the performing stereo matching on the reference speckle pattern according to the scene depth information to obtain the parallax speckle pattern includes:

determining scene parallax information according to the scene depth information;

and carrying out stereo matching on the reference speckle pattern according to the scene parallax information to obtain the parallax speckle pattern.

7. The method for obtaining the depth map of claim 6, wherein the determining scene disparity information according to the scene depth information comprises:

calculating the scene disparity information based on the scene depth information and the following expression:

d＝F*(B/z)

wherein d is the scene parallax information, z is the scene depth information, F is the focal length, B is the baseline, and F and B are both preset values.

8. An apparatus for obtaining a depth map, comprising:

the acquisition module is used for acquiring an infrared background image, a reference speckle pattern and scene depth information corresponding to the infrared background image;

the matching module is used for carrying out three-dimensional matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern;

the superposition module is used for superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern;

and the conversion module is used for converting the style migration speckle pattern into a depth map.

9. An electronic device, comprising:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein the content of the first and second substances,

the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of obtaining a depth map of any of claims 1-7.

10. A computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, implements the method of acquiring a depth map according to any one of claims 1 to 7.

Technical Field

The embodiment of the invention relates to the technical field of image processing, in particular to a method and a device for acquiring a depth map, electronic equipment and a storage medium.

Background

For the three-dimensional vision-related industry, constructing a depth map dataset is very important, and it is often desirable to have a large volume depth map dataset that is rich in comprehensive depth map composition. In order to obtain the depth image data of the rich and comprehensive depth image, a plurality of structured light systems are often used for projecting a plurality of different speckle patterns in various scenes, and then the speckle images are collected, so that a speckle image data set formed by a large number of collected speckle images is obtained, and then the speckle images are converted into the depth image to obtain the depth image data set.

However, a large amount of manpower and material resources are consumed to obtain the depth map by actually constructing various scenes and various structured light systems and projecting various speckle patterns, and the resource waste is serious.

Disclosure of Invention

An object of embodiments of the present invention is to provide a method and an apparatus for obtaining a depth map, an electronic device, and a storage medium, which can reduce manpower and material resources consumed in a depth map obtaining process and reduce resource waste.

To achieve the above object, an embodiment of the present invention provides a method for obtaining a depth map, including: acquiring an infrared background image, a reference speckle pattern and scene depth information corresponding to the infrared background image; performing stereo matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern; superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern; and converting the style migration speckle pattern into a depth map.

In order to achieve the above object, an embodiment of the present invention further provides an apparatus for obtaining a depth map, including: the acquisition module is used for acquiring an infrared background image, a reference speckle pattern and scene depth information corresponding to the infrared background image; the matching module is used for carrying out three-dimensional matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern; the superposition module is used for superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern; and the conversion module is used for converting the style migration speckle pattern into a depth map.

To achieve the above object, an embodiment of the present invention further provides an electronic device, including: at least one processor; and a memory communicatively coupled to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of obtaining a depth map as described above.

To achieve the above object, an embodiment of the present invention further provides a computer-readable storage medium storing a computer program, which when executed by a processor implements the method for acquiring a depth map as described above.

According to the method for acquiring the depth map, provided by the embodiment of the invention, after the infrared background map, the reference speckle pattern and the scene depth information corresponding to the infrared background map are acquired, the reference speckle pattern is subjected to stereo matching according to the scene depth information to obtain the parallax speckle pattern, and the depth information corresponding to the infrared background map is given to the reference speckle pattern, so that the scene depth information is not changed after the parallax speckle pattern is superposed on the infrared background map, namely, under the condition that the scene is not changed, the moving speckle map with the style different from that of the speckle map corresponding to the infrared background map can be obtained, and then the new speckle map can be obtained based on the new speckle map. That is to say, the new depth map can be obtained through image data processing, manual collection in an actual scene is not needed, waste of manpower and material resources is avoided, and resources are saved.

In addition, the method for acquiring a depth map provided by the embodiment of the present invention, where the acquiring of the infrared background map and the scene depth information corresponding to the infrared background map includes: obtaining a speckle pattern; performing speckle extraction on the speckle pattern to obtain a scene speckle pattern; carrying out image subtraction on the speckle pattern and the scene speckle pattern to obtain an initial infrared image; carrying out dodging treatment on the initial infrared image to obtain the infrared background image; and performing depth recovery on the scene speckle pattern to obtain the scene depth information. The method can obtain the infrared background image and the scene information corresponding to the infrared background image by using speckle extraction and depth recovery on the basis of the speckle pattern, and is simple, efficient and easy to implement.

In addition, the method for obtaining a depth map provided by the embodiment of the present invention, which performs speckle extraction on the speckle pattern to obtain a scene speckle pattern, includes: carrying out image filtering processing on the speckle pattern; performing background subtraction on the speckle pattern after the filtering processing; and carrying out binarization and connected region detection on the speckle pattern after background subtraction to obtain the scene speckle pattern. Accurate scene speckle patterns can be obtained through filtering processing, background subtraction, binarization and connected region detection, so that accurate scene depth information and infrared background images can be obtained subsequently according to the accurate scene speckle patterns.

In addition, according to the method for acquiring the depth map provided by the embodiment of the invention, the reference speckle pattern is different from the scene speckle pattern. By setting the reference speckle pattern to be different from the scene speckle pattern, the parallax speckle pattern obtained based on the reference speckle pattern is ensured to be different from the speckle pattern in the speckle pattern, namely the speckle pattern in the style migration speckle pattern is different from the speckle pattern in the original speckle pattern corresponding to the infrared background pattern, and then the style migration speckle pattern is different from the original speckle pattern corresponding to the infrared background pattern, and the depth map obtained based on the style migration speckle pattern is different from the depth map corresponding to the original speckle pattern.

In addition, the method for acquiring a depth map provided by the embodiment of the present invention, where the acquiring of the infrared background map and the scene depth information corresponding to the infrared background map includes: and acquiring an infrared background image and the scene depth information corresponding to the infrared background image from a preset speckle data set. In the speckle data set with the infrared background image and the scene depth information, the infrared speckle image and the scene depth information are directly acquired, so that the subsequent process is rapidly started, and the efficiency of acquiring the depth image is greatly improved.

In addition, the method for obtaining a depth map according to the embodiment of the present invention, in which the reference speckle pattern is stereo-matched according to the scene depth information to obtain a parallax speckle pattern, includes: determining scene parallax information according to the scene depth information; and carrying out stereo matching on the reference speckle pattern according to the scene parallax information to obtain the parallax speckle pattern. Scene parallax information is further obtained through the scene depth information, accurate simulation of the scene is achieved, the condition that the reference speckle pattern is projected onto the object is simulated based on the simulated scene, the parallax speckle pattern is obtained, and the result that the speckle pattern is projected onto the object is obtained.

In addition, the method for obtaining a depth map according to an embodiment of the present invention, where the determining of the scene parallax information according to the scene depth information includes: calculating the scene disparity information based on the scene depth information and the following expression: and d is the scene parallax information, z is the scene depth information, F is the focal length, B is a base line, and F and B are preset values. The method and the device have the advantages that the scene modeling is realized, so that various different scenes can be constructed by changing parameters, the scene can be changed according to requirements, the scene information and the parallax speckle patterns obtained based on the scene information are enriched, and finally the depth maps with rich types can be obtained.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

Fig. 1 is a flowchart of a method for obtaining a depth map according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a device for obtaining a depth map according to another embodiment of the present invention;

fig. 3 is a schematic structural diagram of an electronic device provided in another embodiment of the present invention.

Detailed Description

As known from the background art, in order to obtain depth image data with a large capacity, it is often necessary to acquire speckle images obtained by projecting various speckle patterns by using various structured light systems in various scenes, so as to convert a speckle pattern data set into a depth image data set according to a speckle pattern data set formed by a large number of acquired speckle patterns through conversion from the speckle pattern to the depth image. However, a large amount of manpower and material resources are needed in the method, and the resource waste is serious.

In order to solve the above problem, an embodiment of the present invention provides a method for obtaining a depth map, including: acquiring an infrared background image, a reference speckle pattern and scene depth information corresponding to the infrared background image; performing stereo matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern; superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern; and converting the style migration speckle pattern into a depth map.

According to the method for acquiring the depth map, provided by the embodiment of the invention, after the infrared background map, the reference speckle pattern and the scene depth information corresponding to the infrared background map are acquired, the reference speckle pattern is subjected to stereo matching according to the scene depth information to obtain the parallax speckle pattern, and the depth information corresponding to the infrared background map is given to the reference speckle pattern, so that after the parallax speckle pattern is superposed on the infrared background map, the scene depth information is unchanged, namely under the condition that the scene is unchanged, the style of the shifted speckle pattern different from that of the speckle pattern corresponding to the infrared background map is obtained, and a new speckle pattern is obtained, and further the new depth map can be obtained based on the new speckle pattern. That is to say, the new depth map can be obtained through image data processing, manual collection in an actual scene is not needed, waste of manpower and material resources is avoided, and resources are saved.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present application in various embodiments of the present invention. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments.

The following embodiments are divided for convenience of description, and should not constitute any limitation to the specific implementation manner of the present invention, and the embodiments may be mutually incorporated and referred to without contradiction.

An embodiment of the present invention provides a method for obtaining a depth map, which is applied to an electronic device such as a computer, and a flow of the method for obtaining a depth map is shown in fig. 1, where the method includes:

step 101, acquiring scene depth information corresponding to an infrared background image, a reference speckle pattern and the infrared background image.

In this embodiment, the infrared background image is an image obtained by subtracting a speckle pattern from a speckle pattern, the scene depth information corresponding to the infrared background image is depth information in a scene where the speckle pattern corresponding to the infrared background image is located, the reference speckle pattern is a preset speckle pattern, the reference speckle pattern can be derived from different projectors, and the size, shape, density and number of speckle spots in the reference speckle pattern are not limited in this embodiment.

Specifically, in a case that the infrared background map and the scene depth information corresponding to the infrared background map cannot be directly obtained, step 101 may include: obtaining a speckle pattern, performing speckle extraction on the speckle pattern to obtain a scene speckle pattern, performing image subtraction on the speckle pattern and the scene speckle pattern to obtain an initial infrared image, performing dodging processing on the initial infrared image to obtain an infrared background image, performing depth recovery on the scene speckle pattern to obtain scene depth information, wherein the performing speckle extraction on the speckle pattern to obtain the scene speckle pattern can include: carrying out image filtering processing on the speckle pattern, carrying out background subtraction on the speckle pattern after filtering processing, and carrying out binarization and connected region detection on the speckle pattern after background subtraction to obtain a scene speckle pattern; under the condition that the infrared background image and the scene depth information corresponding to the infrared background image can be directly obtained, step 101 does not need to perform additional processing, and the scene depth information corresponding to the infrared background image and the infrared background image is directly obtained from a preset speckle data set containing the scene depth information corresponding to the infrared background image and the infrared background image.

It should be noted that, when the speckle pattern is processed to obtain the infrared background image and the scene depth information corresponding to the infrared background image, the obtained speckle pattern needs to be different from the original speckle pattern corresponding to the speckle pattern, which is projected onto the object, and the difference can be reflected in the size, shape, density, number and the like of the speckle spots of the original speckle pattern and the reference speckle pattern, so as to ensure that the subsequently obtained style transition image is different from the speckle pattern obtained at that time.

The following description will be given taking a computer as an example, which has a preset speckle pattern data set and is executed by the computer.

In one example, it is assumed that data in a preset speckle data set is a speckle pattern, a user inputs an address of the speckle data set on a human-computer interaction interface of a computer, the address may be a local memory of the computer or an address of a server and the like providing the speckle data set for the user, the computer accesses the address and reads the speckle pattern stored in the address after reading the address input by the user, a preset speckle extraction algorithm in the computer is called and the read speckle pattern is used as an input, and a result output by the speckle extraction algorithm is a scene pattern, wherein the speckle extraction algorithm comprises image filtering preprocessing, background subtraction, binarization and connected region detection processing; and then, performing pixel-by-pixel subtraction on the read speckle pattern and the obtained scene speckle pattern to obtain an initial infrared image, wherein the initial infrared image obtained by image subtraction may have edge lines at the position of the original scene speckle pattern, and the background is not uniform, so that the background image needs to be subjected to dodging, namely, the computer continuously calls a pre-stored dodging algorithm, the speckle pattern and the background infrared image are used as input of a dodging algorithm to obtain an infrared background image which is output by the dodging algorithm and keeps consistent with the brightness and contrast of a background area of the speckle pattern, wherein the dodging algorithm can be a Wallis dodging algorithm, the read brightness and contrast of the background area of the speckle pattern are used as a dodging template in the Wallis dodging algorithm, and the area of the speckle pattern in the initial infrared image is used as a dodging object of the Wallis dodging algorithm, and the brightness and contrast of the output infrared background image are used as, The contrast is uniform, meanwhile, the computer can call the pre-stored depth recovery algorithm in parallel, the scene speckle pattern is used as the input of the depth recovery algorithm, and the scene depth information output by the depth recovery algorithm is obtained.

It should be noted that, the above is only a specific example of the speckle extraction algorithm and the dodging algorithm, and in other examples, other speckle extraction algorithms and other dodging algorithms may also be used, which is not described in detail here.

In another example, assuming that the data in the preset speckle data set are an infrared background image and an infrared background image, a user inputs an address of the speckle data set on a human-computer interaction interface of a computer, and after the computer reads the address input by the user, the computer accesses the address and reads the infrared background image and the infrared background image stored in the address.

And 102, performing stereo matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern.

For a speckle structured light system, the speckle structured light system may include an optical sensor-infrared lens with a focal length F and a speckle projector, where the speckle projector is used to project a speckle pattern onto an object such as an object and a human face, and the optical sensor-infrared lens is used to collect an image when the object such as the object and the human face projects the speckle pattern, that is, a speckle pattern, and the following expression is known according to the principle of triangulation:

z＝F*(B/d)

wherein, B represents a baseline in the speckle structure optical system, F represents a focal length of an infrared lens as an optical sensor in the speckle structure optical system, d represents a parallax, and z represents depth information of an object in a scene, namely field depth information.

In particular, considering that stereo matching is actually performed using disparity information, and it is known from the above expression that disparity is related to scene depth, step 102 may include: determining scene parallax information according to the scene depth information, and performing stereo matching on the reference speckle pattern according to the scene parallax information to obtain the parallax speckle pattern, wherein the above expression shows that determining the scene parallax information according to the scene depth information can be obtained by the following expression:

d＝F*(B/z)

wherein d is scene parallax information, z is scene depth information, F is a focal length, B is a base line, and F and B are preset values.

In one example, the user sets the focal length F and the baseline B by issuing an instruction, which is equivalent to the confirmation that the speckle pattern is obtained as a confirmation of the speckle structured light system used, and then the computer performs parallax processing on the reference speckle pattern based on the above expression, wherein the parallax value is used as a difference between the abscissa of the pixel points on the same line or several lines of the reference speckle pattern and the parallax speckle pattern.

It is worth mentioning that through the stereo matching, the purpose that the reference speckle pattern is mapped to the surfaces of the objects such as the object and the face can be simulated without actually constructing a scene, and the result that the reference speckle pattern is mapped to the objects such as the object and the face is obtained.

It should be noted that, in an actual scene, different structured light systems may have different base lines B, and therefore, the change of the structured light system may be simulated by adjusting the parallax B, so that different parallax information is obtained based on the different base lines B, and further different parallax speckle patterns are obtained, thereby realizing the simulation of obtaining speckle patterns by using the different structured light systems.

That is to say, the baseline B may be set for a plurality of times, and different values are set each time, so that different parallax images are obtained by stereo matching the reference speckle pattern under the condition that the field depth information z is constant, thereby obtaining different parallax speckle patterns in the subsequent process, and obtaining different style migration speckle patterns after the different parallax speckle patterns are superimposed on the infrared background image. At this time, the step of step 102 may include: determining baselines of the infrared lens and the projector lens; and determining scene visual inspection information according to the baseline and the scene depth information, and performing stereo matching on the reference speckle pattern according to the scene parallax information.

And step 103, superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern.

In one example, superimposing the parallax speckle pattern onto the infrared background map is achieved by computing the sum of pixel values pixel by pixel, resulting in a stylized migratory speckle pattern.

And 104, converting the style migration speckle pattern into a depth map.

After the style migration speckle pattern is obtained, the style of the style migration speckle pattern is different from that of the speckle pattern corresponding to the infrared background pattern, and even if the same depth recovery technology is used, the style of the obtained depth pattern is different in both a traditional depth recovery algorithm and a depth learning depth recovery algorithm. If different depth recovery techniques are used, different styles of depth images can be formed for the same speckle image, so that the depth recovery technique with the best adaptability can be obtained for the speckle image of a certain style.

The steps of the above methods are divided for clarity, and the implementation may be combined into one step or split some steps, and the steps are divided into multiple steps, so long as the same logical relationship is included, which are all within the protection scope of the present patent; it is within the scope of the patent to add insignificant modifications to the algorithms or processes or to introduce insignificant design changes to the core design without changing the algorithms or processes.

Another aspect of the embodiments of the present invention further provides an apparatus for obtaining a depth map, as shown in fig. 2, including:

the acquiring module 201 is configured to acquire the infrared background image, the reference speckle pattern, and scene depth information corresponding to the infrared background image.

And the matching module 202 is configured to perform stereo matching on the reference speckle pattern according to the scene depth information to obtain a parallax speckle pattern.

And the superposition module 203 is used for superposing the parallax speckle pattern on the infrared background image to obtain a style migration speckle pattern.

A conversion module 204, configured to convert the style migration speckle pattern into a depth map.

It should be understood that the present embodiment is a device embodiment corresponding to an embodiment of the method for acquiring a depth map, and the present embodiment may be implemented in cooperation with an embodiment of the method for acquiring a depth map. Related technical details mentioned in the embodiment of the method for obtaining a depth map are still valid in this embodiment, and are not described herein again in order to reduce repetition. Accordingly, the related art details mentioned in the present embodiment can also be applied to the embodiment of the method for acquiring a depth map.

It should be noted that, all the modules involved in this embodiment are logic modules, and in practical application, one logic unit may be one physical unit, may also be a part of one physical unit, and may also be implemented by a combination of multiple physical units. In addition, in order to highlight the innovative part of the present invention, a unit which is not so closely related to solve the technical problem proposed by the present invention is not introduced in the present embodiment, but this does not indicate that there is no other unit in the present embodiment.

Another aspect of the embodiments of the present application further provides an electronic device, as shown in fig. 3, including: comprises at least one processor 301; and a memory 302 communicatively coupled to the at least one processor 301; the memory 302 stores instructions executable by the at least one processor 301, and the instructions are executed by the at least one processor 301, so that the at least one processor 301 can execute the method for acquiring the depth map described in any one of the above method embodiments.

Where the memory 302 and the processor 301 are coupled in a bus, the bus may comprise any number of interconnected buses and bridges, the buses coupling one or more of the various circuits of the processor 301 and the memory 302. The bus may also connect various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver may be one element or a plurality of elements, such as a plurality of receivers and transmitters, providing a means for communicating with various other apparatus over a transmission medium. The data processed by the processor 301 is transmitted over a wireless medium via an antenna, which further receives the data and transmits the data to the processor 301.

The processor 301 is responsible for managing the bus and general processing and may also provide various functions including timing, peripheral interfaces, voltage regulation, power management, and other control functions. And memory 302 may be used to store data used by processor 301 in performing operations.

Another aspect of the embodiments of the present invention also provides a computer-readable storage medium storing a computer program. The computer program realizes the above-described method embodiments when executed by a processor.

Those skilled in the art can understand that all or part of the steps in the method of the foregoing embodiments may be implemented by a program to instruct related hardware, where the program is stored in a storage medium and includes several instructions to enable a device (which may be a single chip, a chip, etc.) or a processor (processor) to execute all or part of the steps of the method described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific embodiments for practicing the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.