JP2018019220A - Psychological factor score estimation value calculation device, psychological factor score estimation value calculation method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a video service designer to estimate a psychological factor score of a psychological factor which is an appeal point of the service on the basis of the video image parameters including a resolution, a frame rate and a bit depth.SOLUTION: A psychological factor score estimation value calculation device comprises: input means which receives inputs of one psychological factor and one or more video image parameters; storage means which stores a coefficient of a formula for calculating a psychological factor score estimation value on the basis of the video image parameters for each of a plurality of psychological factors; calculation means which reads a coefficient corresponding to the psychological factor input by the input means from the storage means and calculates the psychological factor score estimation value for the psychological factor by inputting the video image parameters that were input by the input means to the formula to which the coefficient is applied; and output means which outputs the psychological factor score estimation value calculated by the calculation means.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for estimating a psychological factor score which is a value of a sensation received by a user from psychological factors (eg, aesthetic feeling, dynamic feeling, etc.) in a video communication service such as a video distribution service and a videophone service.

  In order to provide a video service with good quality to the user, it is important to design the system so that the video quality experienced by the user is good before providing the service. In order to implement these, a video quality quantification method capable of appropriately evaluating the quality of the video experienced by the user is necessary.

  Methods for quantifying video quality include a subjective quality evaluation method (for example, see Non-Patent Document 1) and a quality estimation technique (for example, see Non-Patent Documents 2 and 3). The subjective quality evaluation method requires a large number of users to evaluate video images in a facility where the evaluation environment (room illuminance, room noise, etc.) can be reproduced. Therefore, evaluation takes time. Therefore, development of a quality estimation technique for outputting a video quality value from a media signal or a physical feature amount related to service or communication is being developed (for example, see Non-Patent Documents 2, 3, and 4).

  Video quality estimation techniques are classified based on input information. Depending on the amount of input information, the amount of calculation and the quality estimation accuracy differ, so it is necessary to use them according to the purpose of use. For example, when a video service designer uses a quality estimation technique for quality design before service provision, a video quality estimation technique that receives network and terminal quality design parameters (for example, bit rate and packet loss rate) as input. Is used. Thereby, it is possible to grasp what quality design parameter value needs to be set in order to achieve the target video quality (Non-Patent Document 4).

  On the other hand, ultra high-definition video services such as 4K / 8K video have attracted attention in recent years. In the 4K / 8K video service, the resolution, the frame rate, and the bit depth are improved compared to the conventional full HD video service (Non-Patent Document 5). Therefore, it is expected that natural video display becomes possible, and not only high video quality but also a richer sense (psychological factor) can be experienced.

ITU-T recommendation P.910 "Subjective video quality assessment methods for multimedia applications" ITU-T recommendation J.247 "Objective perceptual multimedia video quality measurement in the presence of a full reference" ITU-T Recommendation J.341 "Objective perceptual multimedia video quality measurement of HDTV for digital cable television in the presence of a full reference" Quality design technology for video communication services (http://www.ntt.co.jp/journal/0901/files/jn200901016.pdf) Upcoming 8K broadcast (https://www.nhk.or.jp/digital/b_tech/pdf2015/nhk2015_02_07.pdf)

  In order to provide a richer ultra-high-definition video service, the video service should be designed in consideration of not only video quality but also psychological factors (eg, aesthetic feeling, dynamic feeling, etc.) unique to ultra-high-definition video. is necessary. For example, if a travel program with a more beautiful video can be provided, the user can clearly have an image of the presented video space, such as the scenery or meal of the travel destination, and the user's satisfaction with the video service (user Satisfaction) is improved. Also, if a sports program that can feel the power of the game and the enthusiasm can be provided, the user can feel a sense of dynamism as if he / she was watching in the auditorium, and the user satisfaction is improved. In order to provide travel programs with high aesthetics and sports programs with high dynamism, it is necessary to design each program so that the aesthetic sensation and dynamism are maintained to some extent.

  The present invention has been made in view of the above points, and a video service designer estimates a psychological factor score of a psychological factor as a service appeal point based on video parameters such as resolution, frame rate, and bit depth. It is an object to provide a technology that makes it possible.

According to the disclosed technology, input means for receiving input of one psychological factor and one or more video parameters;
Storage means for holding a coefficient of a mathematical formula for calculating a psychological factor score estimate based on video parameters for each of a plurality of psychological factors;
A coefficient corresponding to the psychological factor input by the input unit is read from the storage unit, and the video parameter input by the input unit is input to the mathematical formula to which the coefficient is applied, whereby the psychological factor for the psychological factor is input. A calculation means for calculating a factor score estimate;
An apparatus for calculating a psychological factor score estimate value, comprising: output means for outputting a psychological factor score estimate value calculated by the calculating means is provided.

  According to the disclosed technology, a video service designer can estimate a psychological factor score of a psychological factor as a service appeal point based on video parameters such as resolution, frame rate, and bit depth.

It is a figure which shows the example of a relationship between the image | video parameter and psychological factor score in embodiment of this invention. It is a figure which shows the structural example of the psychological factor score estimation apparatus 10 in embodiment of this invention. 2 is a hardware configuration diagram of a psychological factor score estimation apparatus 10. FIG. It is a figure which shows the example of the coefficient of the psychological factor score derivation function stored in the memory | storage part 13 of the psychological factor score estimation apparatus.

  Hereinafter, an embodiment (this embodiment) of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment. In this embodiment, five types of psychological factors and three types of video parameters are used, but these are examples. All of these may not be used, or psychological factors and video parameters other than these may be used.

(Outline of the embodiment)
In order to design a video service based on psychological factors, it is necessary to grasp the relationship between video parameters (resolution, frame rate, bit depth) and sensory values (psychological factor scores) that the user receives from psychological factors. Here, FIG. 1 illustrates the relationship between video parameters and psychological factor scores. Here, as an example, five psychological factors such as aesthetic feeling, dynamic feeling, natural feeling, open feeling, and three-dimensional feeling are shown. The relationship shown in FIG. 1 is obtained based on the subjective quality evaluation experiment result, and can be used to determine the psychological factor score derivation function, as will be described later.

  1A shows the relationship between the resolution and the psychological factor score when the frame rate and the bit depth are fixed, and FIG. 1B shows the frame rate and the psychological factor score when the resolution and the bit depth are fixed. FIG. 1C shows the relationship between the bit depth and the psychological factor score when the resolution and the frame rate are fixed.

  As can be seen from FIG. 1A, when the resolution changes, the image becomes clearer, and thus the aesthetic feeling and the natural feeling are easily improved. As can be seen from FIG. 1B, when the frame rate is changed, the movement becomes smoother, so that the dynamic feeling and the natural feeling are easily improved. As can be seen from FIG. 1C, when the bit depth changes, the edge of the subject stands out, so that the stereoscopic effect and the open feeling are easily improved. As described above, the influence of the image parameter on the psychological factor score is different.

  From FIGS. 1A to 1C, it is effective to improve the resolution when it is desired to improve the aesthetic feeling, and it is effective to increase the frame rate when it is desired to improve the dynamic feeling. In order to improve the natural feeling, it is effective to improve the resolution and the frame rate, and in the case of improving the stereoscopic effect and the open feeling, it is effective to improve the bit depth. Therefore, in order to improve a specific psychological factor score, a psychological factor score estimation technique that formulates the relationship between the video parameter and the psychological factor score is necessary.

  On the other hand, in FIGS. 1A to 1C, the relationship between one video parameter and a psychological factor score is shown. However, in the 4K / 8K video service, two or more video parameters may be changed simultaneously. . Therefore, it is also necessary to quantify the synergistic effect when two or more video parameters are changed simultaneously. Here, FIG. 1D shows the relationship between video parameters and psychological factor scores when all three video parameters are changed. Originally, FIG. 1 (d) is a four-axis graph of resolution, frame rate, bit depth, and psychological factor score. For convenience of illustration, here, 2K video is 2K30P8bit, 4K video is 4K60P10bit, In consideration of the fact that 8K120P12bit parameter combinations are often used in 8K video, the three patterns are described as examples.

  In FIG. 1 (d), as in FIGS. 1 (a) to 1 (c), the degree of change in the psychological factor score caused by changing a plurality of video parameters varies depending on each psychological factor. Therefore, there is a need for a technique for deriving each psychological factor score from video parameters even when a plurality of video parameters are changed simultaneously instead of only one.

  In the present embodiment, a psychological factor score estimation technique is realized by using a psychological factor score derivation function that formulates the relationship between video parameters and psychological factor scores. Further, in this technique, it is possible to derive each psychological factor score from the video parameter even when a plurality of video parameters are changed simultaneously. Hereinafter, the technique according to the present embodiment will be described in detail.

(Configuration of psychological factor score estimation apparatus 10)
In FIG. 2, the structural example of the psychological factor score estimation apparatus 10 in this Embodiment is shown. As illustrated in FIG. 2, the psychological factor score estimation apparatus 10 according to the present exemplary embodiment includes an input unit 11, a psychological factor score estimation unit 12, a storage unit 13, and an output unit 14.

  The input unit 11 receives input of one psychological factor and one or more video parameters. The memory | storage part 13 hold | maintains the coefficient in the numerical formula (henceforth psychological factor score derivation function) for calculating a psychological factor score estimated value about each of several psychological factors. The storage unit 13 may be referred to as a coefficient DB (database).

  The psychological factor score estimation unit 12 reads a coefficient corresponding to the psychological factor input from the input unit 11 from the storage unit 13, and uses the video parameter input from the input unit 11 as a psychological factor score derivation function to which the coefficient is applied. By inputting, a psychological factor score derivation function is calculated, and an estimated psychological factor score corresponding to the psychological factor input from the input unit 11 is calculated. The output unit 14 outputs the psychological factor score estimated value calculated by the psychological factor score estimating unit 12.

  In this embodiment, as shown in FIG. 2, the psychological factor i and the resolution x1, the frame rate x2, and the bit depth x3 as video parameters are input to the psychological factor score estimating apparatus 10 and the above calculation is performed. , Output psychological factor score S.

  The psychological factor score estimator 12 may include a function of a psychological factor score derivation function, and the psychological factor score may be calculated by applying a coefficient read from the storage unit 13 to the function. The function and the coefficient may be stored in the storage unit 13, and the psychological factor score estimation unit 12 may read the psychological factor score derivation function and the coefficient from the storage unit 13 and calculate the psychological factor score.

  The psychological factor score estimation apparatus 10 according to the present embodiment can be realized, for example, by causing one or a plurality of computers to execute a program describing the processing contents described in the present embodiment. In other words, the function of the psychological factor score estimating apparatus 10 executes a program corresponding to the process executed by the psychological factor score estimating apparatus 10 using hardware resources such as a CPU, a memory, and a hard disk built in the computer. This can be realized by doing so. Further, the program can be recorded on a computer-readable recording medium (portable memory or the like), stored, or distributed. It is also possible to provide the program through a network such as the Internet or electronic mail.

  FIG. 3 is a diagram illustrating a hardware configuration example when the psychological factor score estimation apparatus 10 is realized by a computer. The psychological factor score estimation device 10 in FIG. 3 includes a drive device 108, an auxiliary storage device 102, a memory device 103, a CPU 104, an interface device 105, a display device 106, an input device 107, and the like that are mutually connected by a bus B. Have.

  A program that realizes processing in the psychological factor score estimation apparatus 10 is provided by a recording medium 101 such as a CD-ROM or a memory card, for example. When the recording medium 101 storing the program is set in the drive device 108, the program is installed from the recording medium 101 to the auxiliary storage device 102 via the drive device 108. However, the program need not be installed from the recording medium 101 and may be downloaded from another computer via a network. The auxiliary storage device 102 stores the installed program and also stores necessary files and data.

  The memory device 103 reads the program from the auxiliary storage device 102 and stores it when there is an instruction to start the program. The CPU 104 realizes functions related to the psychological factor score estimation device 10 according to a program stored in the memory device 103. The interface device 105 is used as an interface for connecting to a network. The display device 106 displays a GUI (Graphical User Interface) or the like by a program. The input device 107 includes a keyboard and mouse, buttons, a touch panel, and the like, and is used to input various operation instructions.

(Psychological factor score calculation processing in the psychological factor score estimation unit 12)
Next, the psychological factor score calculation process in the psychological factor score estimating unit 12 will be described in detail.

  When the psychological factor i and the video parameters x1 to x3 are input from the input unit 11, the psychological factor score estimation unit 12 reads a coefficient corresponding to the psychological factor i from the storage unit 13. Then, the psychological factor score estimation unit 12 inputs the video parameters x1 to x3 to the psychological factor score derivation function to which the coefficient is applied, calculates the psychological factor score derivation function, and calculates the psychological factor score S. . The calculated psychological factor score S is output from the output unit 14.

An example of the psychological factor score derivation function in the present embodiment is shown as equation (1) below.
Si (x1, x2, x3) = (αi1 × exp (βi1 × x1)) × (αi2 × exp (βi2 × x2)) × (αi3 × exp (βi3 × x3)) Equation (1)
Here, x1, x2, and x3 in Equation (1) are a resolution, a frame rate, and a bit depth, respectively. Regarding psychological factor i, i = 1 indicates aesthetic feeling, i = 2 indicates dynamic feeling, i = 3 indicates natural feeling, i = 4 indicates open feeling, and i = 5 indicates three-dimensional feeling.

  The psychological factor score derivation function of Equation (1) is a function obtained by formulating the relationship shown in FIG. More specifically, a subjective quality evaluation experiment is performed in which the video parameters x1 to x3 are changed to various values in advance to evaluate psychological factors i such as aesthetic feeling and dynamic feeling. Then, the function form (in this case, exp is set so as to match the relationship between the video parameter and the psychological factor score obtained in the subjective quality evaluation experiment (eg, the curves shown in FIGS. 1A to 1C). The coefficients αij and βij (i = 1 to 5, j = 1 to 3) are determined for each video parameter and for each psychological factor i. The determined coefficient is stored in the storage unit 13.

  In the present embodiment, as shown in FIGS. 1A to 1C, the relationship between video parameters and psychological factor scores varies depending on the video parameters, and as shown in FIG. The psychological factor score derivation function is determined by formulating in consideration of the need to take into account the synergistic effects. As shown in FIGS. 1A to 1C, since the relationship between the video parameter and the psychological factor score differs depending on the psychological factor, the coefficient of the psychological factor score derivation function is determined for each video parameter and psychological factor. Is set. FIG. 4 shows an example of the coefficients stored in the storage unit 13. As shown in FIG. 4, coefficients α and β are determined and stored for each video parameter and psychological factor.

<Reflection of synergies between video parameters>
On the right side of Equation (1), (αi1 × exp (βi1 × x1)) is the relationship between the resolution and the score of psychological factor i under a specific frame rate and bit depth (eg, FIG. 1A). ) Is obtained by subjective quality evaluation and fitted to the relationship (curve). (αi2 × exp (βi2 × x2)) is obtained by subjecting a relationship between the frame rate and the score of psychological factor i (for example, FIG. 1 (b)) by subjective quality evaluation under a specific resolution and bit depth, This is an equation that fits the relationship (curve). (αi3 × exp (βi3 × x3)) is obtained by subjective quality assessment of the relationship between the bit depth and the score of psychological factor i (eg, FIG. 1 (c)) under a certain resolution and frame rate. This is an equation that fits the relationship (curve).

  In the formula (1), the video parameter is multiplied by multiplying (αi1 × exp (βi1 × x1)), (αi2 × exp (βi2 × x2)) and (αi3 × exp (βi3 × x3)). It reflects the synergistic effect of each other.

  Note that, for example, in (αi1 × exp (βi1 × x1)), the characteristics of the relationship between the resolution and the score of the psychological factor i even when the combination condition of the frame rate and the bit depth changes (the score increases nonlinearly as the resolution increases) In this embodiment, the coefficients (αi1, βi1) relating to the resolution are the same even when the combination condition of the frame rate and the bit depth is changed. However, this is an example, and the coefficients (αi1, βi1) relating to resolution may be different values depending on the combination conditions of the frame rate and the bit depth. The same applies to the coefficient relating to the frame rate and the coefficient relating to the bit depth, which may be the same even if the condition changes, or which may be different depending on the condition.

<Other examples of psychological factor score derivation functions>
As described above, in the present embodiment, the relationship between each video parameter and the psychological factor score is formulated by a nonlinear function, but this is an example. For example, it may be expressed by a linear function. Further, in order to reflect the synergistic effect between the video parameters, the formula relating to each video parameter is multiplied, but these may be added.

  When adding, Expression (1) is changed to Expression (2) below.

Si (x1, x2, x3) = (αi1 × exp (βi1 × x1)) + (αi2 × exp (βi2 × x2)) + (αi3 × exp (βi3 × x3)) Equation (2)
Since the service designer basically knows all the values of resolution x1, frame rate x2, and bit depth x3, it is possible to use all of them as inputs for equation (1) or equation (2). it can. Therefore, the psychological factor score can be derived by using the formula (1) or the formula (2).

  However, for example, if the correspondence between the bit depth and the psychological factor and the correspondence between the frame rate and the psychological factor are unnecessary or the correspondence is not obtained in the service design, that is, only the correspondence between the resolution and the psychological factor score. If it is obtained, the psychological factor score derivation function can be simplified as shown in Equation (3).

Si (x1) = (αi1 × exp (βi1 × x1)) Equation (3)
The coefficients α i1 and β i1 (i = 1 to 5) in the above formula are determined based on the method described so far, that is, based on the result of subjective quality evaluation experiment performed in advance, and stored in the storage unit 13. To do.

  In addition, the above is an example in the case of using the correspondence between resolution and psychological factor score, but also includes the case of using the correspondence between bit depth and psychological factor and the case of using the correspondence between frame rate and psychological factor. A more general formula can be expressed as the following formula (4).

Sj (xi) = αij × exp (βij × xj) Equation (4)
The coefficients αij and βij (i = 1 to 5, j = 1 to 3) are determined based on the results of subjective quality evaluation experiments performed in advance and stored in the storage unit 13 as described above. And

  As described above, the psychological factor score is derived by using a psychological factor score deriving function that formulates the relationship between the video parameter and the psychological factor score for each psychological factor.

(Summary of the embodiment, effects)
As described above, according to the present embodiment, the input means for receiving input of one psychological factor and one or more video parameters, and the coefficient of the mathematical formula for calculating the psychological factor score estimate based on the video parameters Storage means for each of a plurality of psychological factors, and a coefficient corresponding to the psychological factor input by the input means is read from the storage means, and the mathematical expression to which the coefficient is applied is read by the input means. A calculation unit that calculates a psychological factor score estimate value for the psychological factor by inputting the input video parameter; and an output unit that outputs the psychological factor score estimate value calculated by the calculation unit. A psychological factor score estimated value calculation apparatus is provided.

  The psychological factor score estimation device 10 in the embodiment is an example of a psychological factor score estimated value calculation device, the input unit 11 is an example of an input unit, and the psychological factor score estimation unit 12 is an example of a calculation unit. The storage unit 13 is an example of a storage unit, and the output unit 14 is an example of an output unit.

  The formula is a formula that formulates the relationship between the video parameter obtained based on the subjective quality evaluation experiment result and the psychological factor score, for example. Further, the mathematical formula is obtained by obtaining a mathematical formula from the relationship between the video parameter and the psychological factor score for each of the plurality of video parameters and combining the mathematical formula obtained for each of the plurality of video parameters. It may be a mathematical formula.

  As an example of the above combination method, there is a method of multiplying or adding mathematical expressions as described above.

  According to the technology according to the present embodiment, the video service designer can estimate the psychological factor score of the psychological factor as the service appeal point based on video parameters such as resolution, frame rate, and bit depth. .

  In addition, the video service designer can grasp which of the video parameters such as resolution, frame rate, and bit depth can achieve the target psychological factor score by changing the parameters. As a result, a video service with higher user satisfaction can be provided.

  Although the present embodiment has been described above, the present invention is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. Is possible.

DESCRIPTION OF SYMBOLS 10 Psychological factor score estimation apparatus 11 Input part 12 Psychological factor score estimation part 13 Memory | storage part 14 Output part
S Psychological factor score
i Psychological factors
x1 resolution
x2 frame rate
x3 Bit depth α, β Psychological factor score derivation function

Claims (7)

Input means for receiving input of one psychological factor and one or more video parameters;
Storage means for holding a coefficient of a mathematical formula for calculating a psychological factor score estimate based on video parameters for each of a plurality of psychological factors;
A coefficient corresponding to the psychological factor input by the input unit is read from the storage unit, and the video parameter input by the input unit is input to the mathematical formula to which the coefficient is applied, whereby the psychological factor for the psychological factor is input. A calculation means for calculating a factor score estimate;
The psychological factor score estimated value calculation apparatus comprising: output means for outputting the psychological factor score estimated value calculated by the calculating means. The psychological factor score estimated value calculation apparatus according to claim 1, wherein the mathematical formula is a mathematical formula that formulates a relationship between a video parameter obtained based on a subjective quality evaluation experiment result and a psychological factor score. The mathematical formula is a mathematical formula obtained by obtaining a mathematical formula from the relationship between the video parameter and the psychological factor score for each of the plurality of video parameters and combining the mathematical formulas obtained for each of the plurality of video parameters. The psychological factor score estimated value calculation apparatus according to claim 1, wherein the psychological factor score estimated value calculation apparatus is provided. Psychological factor score estimation value calculation executed by a psychological factor score estimation value calculation device including a storage unit that holds, for each of a plurality of psychological factors, a coefficient for calculating a psychological factor score estimation value based on the video parameter A method,
An input step for receiving input of one psychological factor and one or more video parameters;
A coefficient corresponding to the psychological factor input in the input step is read out from the storage means, and the video parameter input in the input step is input to the mathematical formula to which the coefficient is applied, whereby the psychology for the psychological factor is input. A calculation step of calculating a factor score estimate;
An output step of outputting the psychological factor score estimate calculated by the calculating step. The psychological factor score estimated value calculation method according to claim 4, wherein the mathematical formula is a mathematical formula that formulates a relationship between a video parameter obtained based on a subjective quality evaluation experiment result and a psychological factor score. The mathematical formula is a mathematical formula obtained by obtaining a mathematical formula from the relationship between the video parameter and the psychological factor score for each of the plurality of video parameters and combining the mathematical formulas obtained for each of the plurality of video parameters. The psychological factor score estimated value calculation method according to claim 4, wherein the psychological factor score estimated value is calculated.   The program for functioning a computer as each means in the psychological factor score estimated value calculation apparatus of any one of Claims 1 thru | or 3.

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