JP2009171023A - Image quality evaluation apparatus, image quality evaluation method, program for image quality evaluation, and video reception terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To calculate an image quality degradation degree close to subjective evaluation from received video encoded data only. <P>SOLUTION: When deciding that data of which decoding processing is performed include a discontinuous point, a degraded area detection part 172 specifies input data from the discontinuous point to the next decoding processing synchronous position, generates information relating to an image area wherein image quality is degraded by the influence of the discontinuous point as the result of the decoding processing as degraded area information, and outputs it to a degraded area importance degree calculation part 173. The degraded area importance degree calculation part 173 calculates an importance degree according to subjectivity on the image frame of a degraded area from the degraded area information received from the degraded area detection part 172, and notifies an image quality degradation degree calculation part 174 of the degraded area information and the importance degree. The image quality degradation degree calculation part 174 calculates an image quality degradation degree on the basis of the degraded area information and the importance degree of the degraded area calculated in the degraded area importance degree calculation part 173 for each degraded area detected in the degraded area detection part 172, and outputs the image quality degradation degree to the outside. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an image quality evaluation apparatus, an image quality evaluation method, an image quality evaluation program, and a video reception terminal, and more particularly to an image quality evaluation apparatus, an image quality evaluation method, and an image quality evaluation program for objectively evaluating the image quality at the time of reception of transmitted video. And a video receiving terminal.

  Methods for objectively evaluating video image quality are roughly classified into three types (for example, see Non-Patent Document 1). The first method is a method (Full Reference method) in which an original image and a deteriorated image are directly compared to evaluate image quality. The second method is a method (Reduced Reference method) in which only the feature amount of the original image is transmitted and the image quality is evaluated from the feature amount and the degraded image. The third method is a method (No Reference method) for evaluating the image quality only from the degraded image.

  In an application involving video transmission, there is an upper limit on the transmission path band and it is difficult to transmit the original image, so it is not appropriate to use the Full Reference method on the receiving terminal. In the reduced reference method, it is necessary to multiplex or transmit the feature quantity of the original image via another transmission path. Therefore, in order to introduce the reduced reference method, it is necessary to replace all systems including the transmission device and the transmission path, and thus there is a problem that new operation is difficult. On the other hand, the No Reference method does not require any information on the original image, and only requires replacement of the receiving device for introduction, so that there is an advantage that new operation is easy.

  An image quality evaluation apparatus that evaluates image quality by the No Reference method is disclosed (for example, see Patent Document 1). In the image quality evaluation apparatus described in Patent Document 1, a receiving apparatus that receives data from a transmission path transmits this input data to a decoder, and at the same time, a signal indicating whether or not the input data includes an error. At the same time, the data is transmitted to a decoder so that the decoder can detect data fraud during the decoding process.

  In the image quality evaluation apparatus described in Patent Document 1, when a transmission error such as a packet loss, a bit error, or a delay occurs, the input data is discarded and the data is skipped to the next decoding processing synchronization position. In this image quality evaluation apparatus, the number of samples (number of pixels or the number of blocks composed of a plurality of pixels) that could not be correctly decoded due to the discarding of the input data is totaled and output as the degree of image quality degradation.

ITU-T Recommendation J.143, `` User requirements for objective perceptual video quality measurements in digital cable television '', 2000 Japanese Patent Laid-Open No. 2001-25014

  However, the image quality evaluation apparatus disclosed in Patent Document 1 is configured to simply calculate the degree of image quality degradation, which is a reference for evaluating image quality, by summing up the number of samples that could not be correctly decoded. There is a problem that it is not possible to calculate a near image quality degradation degree.

  The reason is that, for example, when image quality deterioration occurs in the center of the screen and when image quality deterioration occurs in the periphery of the screen, even if the number of samples that could not be decoded correctly is the same, When the user views the video, the image quality is worse when the image quality deterioration occurs in the center of the screen. This is because the user's subjective evaluation cannot be reflected in the image quality deterioration even though it is felt bad.

  The present invention has been made in view of the above points, and provides an image quality evaluation apparatus, an image quality evaluation method, an image quality evaluation program, and a video reception terminal capable of calculating an image quality degradation level closer to subjective evaluation from only received video. With the goal.

  In order to achieve the above object, the image quality evaluation apparatus according to the first aspect of the present invention receives image encoded data to be evaluated for image quality as an input together with discontinuous position information indicating a discontinuous position due to data loss or data error, When decoding image encoded data to generate image data, an image between a discontinuous point in the image encoded data and a decoding process synchronization position that is a position that can be correctly decoded based on the discontinuous position information Based on the information on the degradation area detected by the degradation area detection means that identifies the coded data portion and detects the image area affected by the identified image coding data as the degradation area, and at least the degradation area detection means, Image quality deterioration degree calculating means for calculating an image quality deterioration degree indicating an index of the conspicuousness of the image quality deterioration due to the deteriorated area.

  In order to achieve the above object, the image quality evaluation method according to the second invention uses the encoded image data to be evaluated as an input together with the discontinuous position information indicating the discontinuous position due to data loss or data error. When decoding the encoded image data and generating the image data, based on the discontinuous position information, the interval from the discontinuous point in the encoded image data to the decoding process synchronization position, which is a correct decodable position A first step of specifying the image encoded data portion of the image, a second step of detecting an image region affected by the specified image encoded data as a deteriorated region, and a deteriorated region detected by at least the second step And a third step of calculating an image quality deterioration degree indicating an index of the conspicuousness of the image quality deterioration due to the deteriorated area based on the information of the above.

In order to achieve the above object, an image quality evaluation program according to a third invention is an image quality evaluation program for evaluating the image quality of an image frame obtained by decoding image encoded data by a computer, On the computer,
When receiving encoded image data as an input together with discontinuous position information indicating a discontinuous position due to data loss or data error, and decoding the encoded image data to generate image data, based on the discontinuous position information, A first step of specifying an image encoded data portion between a discontinuous point in the image encoded data and a decoding processing synchronization position that is a position that can be correctly decoded; and an image affected by the specified image encoded data Based on the second step of detecting an area as a deteriorated area and at least information on the deteriorated area detected by the second step, an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area is calculated. And performing the third step.

  Furthermore, in order to achieve the above object, a video receiving terminal according to a fourth aspect of the present invention receives data including image encoded data subject to image quality evaluation from a video distribution server via a transmission path as input, and performs reception processing. An input data generation unit that receives data input via a transmission line and generates encoded image data, and detects discontinuous points due to data loss or data errors in the encoded image data The discontinuous information generating unit that generates discontinuous position information representing the position of the discontinuous point in the image encoded data, the image encoded data and the discontinuous position information are received as input, and the image encoded data is received. And an image quality evaluation unit for calculating the image quality degradation degree of the image frame obtained by decoding, wherein the image quality evaluation unit is configured as in the first invention.

  According to the present invention, the degree of image quality degradation closer to subjective evaluation is calculated as compared to the case of simply adding the number of data samples that could not be decoded correctly and calculating the degree of image quality degradation only from the size of the degraded area. Therefore, image quality evaluation closer to subjective evaluation can be performed.

  Next, each example of the best mode for carrying out the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows a block diagram of a video receiving terminal equipped with a first embodiment of an image quality evaluation apparatus of the present invention. As shown in FIG. 1, the video receiving terminal 100 includes a receiving unit 120 that receives encoded image data compressed from a transmission path 110, an input data generating unit 130, an input data buffer 140, and a discontinuous position information buffer. 160 and an image quality evaluation unit 170A. The input data generation unit 130 includes a discontinuous position information generation unit 150. The image quality evaluation unit 170A constitutes a first embodiment of the image quality evaluation apparatus of the present invention, and includes a decoding processing unit 171, a deteriorated area importance calculation unit 173, and an image quality deterioration degree calculation unit 174. The decryption processing unit 171 has a deteriorated area detection unit 172.

  The receiving unit 120 receives received data from the transmission path 110 and passes it to the input data generating unit 130. The received data includes encoded image data obtained by compressing video data. The input data generation unit 130 extracts encoded image data from the reception data received from the reception unit 120, generates a joined bit string as input data, and supplies the input data to the input data buffer 140.

  Specifically, referring to FIG. 2, the transmission path 110 is an IP (Internet Protocol) network, and the received data is an IP packet including an IP header hi (i is a number indicating the receiving order) and image encoded data di. In the case of 200, the input data generation unit 130 removes the IP header hi from the IP packet 200 of the received data sequentially received according to a predetermined rule, and joins the encoded image data di in the IP packet 200. Then, the data is input to the input data buffer 140.

  At this time, for example, when a packet indicated by 203 in FIG. 2 is lost due to a transmission error or delay, the input data generation unit 130 uses data obtained by connecting the image encoded data d3 and d5 of the packets before and after the lost packet. Since the data is generated and supplied to the input data buffer 140, the data stored in the input data buffer 140 does not include the image encoded data d4 of the missing packet 203, and includes a data discontinuity point 204. Similarly, when a certain bit of received data has an incorrect value during transmission, the image encoded data portion of the incorrect value becomes a discontinuous point.

  In the process of generating input data from received data in the input data generation unit 130, the discontinuous position information generation unit 150 shown in FIG. 1 checks whether there is a discontinuity point in the data. Discontinuous position information indicating the position of the discontinuous point is generated, and the discontinuous position information is supplied to the discontinuous position information buffer 160.

  For example, when the received data is RTP (Real-time Transport Protocol) packetized data, the discontinuous position information generation unit 150 detects a missing packet by checking the RTP number in the RTP header, Can grasp the discontinuous position of data. An error in a bit string can be detected by performing a bit string check such as a cyclic redundancy check or a checksum, and a discontinuous position of data can be determined by making a packet with an error a missing packet. I can grasp.

  As a method for expressing the discontinuous position of data, for example, the discontinuous position may be represented by the number of bits from the beginning of the data input to the input data buffer 140 immediately before, or the number of bits from the first input data. May represent discontinuous positions. Moreover, you may express a discontinuous position using methods other than the method described here.

  Also, the discontinuous position information generation unit 150 does not output information to the discontinuous position information buffer 160 when there is no discontinuous point in the received data, or information indicating that there is no discontinuity in the input data May be supplied to the discontinuous position information buffer 160.

  The decoding processing unit 171 decodes the input data stored in the input data buffer 140. The decoding processing unit 171 does not decode data for one video frame at a time, but performs decoding processing for each smaller unit, that is, for each collection of data smaller than one image frame such as a macroblock or slice. The decoded image data is output to a display device (not shown) connected to the video receiving terminal 100. Here, the above macroblock is a basic unit for performing the encoding / decoding processing, and includes image compression data of a rectangular image area composed of 16 pixels in the horizontal direction and 16 pixels in the vertical direction. A group of a plurality of macroblocks is called a slice.

  When it is determined that the decoded data includes a discontinuous point, the degradation region detection unit 172 specifies input data from the discontinuous point to the next decoding processing synchronization position, Information relating to an image area whose image quality has deteriorated due to the influence of the discontinuous points is generated as degraded area information, and is output to the degraded area importance calculation unit 173.

  Here, the above-described degraded area information is specifically represented by the degraded area size expressed by the number of pixels or macroblocks that could not be decoded correctly, the coordinate positions of the pixels or macroblocks on the image frame, and the like. Position information, color information of the pixels and macroblocks, and information such as the magnitudes of motion vectors corresponding to the macroblocks.

  In addition, the decoding processing unit 171 may perform decoding processing of subsequent image frames using a pixel or macroblock that cannot be correctly decoded due to the influence of data discontinuity as a prediction signal. At this time, the image quality of an image area decoded using a pixel or macroblock that could not be decoded correctly as a prediction signal also deteriorates. The deteriorated area detection unit 172 may further consider such an image area as a deteriorated area.

  The deteriorated area importance calculator 173 calculates the importance of the deteriorated area on the image frame from the deteriorated area information received from the deteriorated area detector 172, and notifies the image quality deterioration degree calculator 174 of the deteriorated area information and importance. To do. This importance indicates the ratio of how easily the deteriorated area is noticeable on an image frame having the deteriorated area.

  As an example, a method for calculating the importance of a deteriorated area based on the position of the deteriorated area will be described below.

  The degraded region importance calculation unit 173 receives from the degraded region detection unit 172 as degraded region information the number of macroblocks that could not be decoded correctly due to data discontinuity and the coordinate information on the image frame of each macroblock. The deteriorated area importance calculation unit 173 calculates the coordinate position of the center of gravity of the deteriorated area from the position information of each macroblock, and the importance is higher as the distance from the center of the screen is closer to the center of the coordinate position. The importance is weighted so that the importance decreases as the distance increases. This is because the deterioration of the image quality is more conspicuous when there is deterioration in the center of the screen than when there is deterioration in the peripheral portion of the screen.

  More specifically, the degree of importance of the deteriorated area is calculated from the reciprocal of the distance from the center of the screen to the center of gravity of the deteriorated area. For example, in FIG. 3, the distance from the center of the image of the degraded area A of the image frame 301 is s. At this time, the importance of the degradation area A is set to 1 / s. Similarly, the importance of the degraded area B of the image frame 302 is 1 / t, the importance of the degraded area C of the image frame 303 is 1 / u, and the importance of the degraded area D is 1 / v.

  However, as a method of calculating importance in the deteriorated region importance calculating unit 173, in the specific example, the reciprocal of the distance from the center of the image frame to the center of gravity of the deteriorated region is used as the importance, but the position information included in the deteriorated region information It is also possible to calculate the importance by other functions using as a parameter.

  In addition to the position of the degraded area, if the degraded area includes a flesh-colored part or a pixel of a specific color or macro block that stands out, the degraded area includes a macroblock with a larger motion vector size. In the case where a pixel or macroblock having a color that is larger than that of the surrounding pixel or macroblock and that has a different color is included in the degraded region, the importance can be calculated with a higher value.

  The image quality degradation degree calculation unit 174 shown in FIG. 1 has the degradation area information and the importance level of the degradation area calculated by the degradation area importance calculation section 173 for each degradation area detected by the degradation area detection unit 172. In addition, an image quality degradation level indicating an index of the conspicuousness of image quality degradation due to the degraded area is calculated, and the image quality degradation level is output to the outside.

  For example, in the case of the method of calculating the importance level of the degraded area based on the position of the degraded area described in the degraded area importance level calculation unit 173, the image quality degradation level calculation unit 174 includes each of the areas detected by the degraded area detection unit 172. For the deteriorated area, the deteriorated area size included in the deteriorated area information and the importance calculated by the deteriorated area importance calculating unit 173 are integrated, and the sum of all the integration results is calculated as the image quality deterioration degree.

  In the specific example shown in FIG. 3, since the size of the degraded area A is a and the degraded area importance is 1 / s, the image quality degradation degree of the image frame 301 is calculated as a / s. Similarly, since the size of the degraded area B is a and the importance is 1 / t, the image degradation level of this frame is calculated as a / t.

  The image quality degradation degree calculation unit 174 integrates the importance calculated by the degradation area importance degree calculation unit 173, whereby the image quality degradation degree of the image frame 301 is a / s and the image quality degradation degree of the image frame 302 is a / t. calculate. Here, the size of the deteriorated area of the image frame 301 and the image frame 302 is the same as a, but the deteriorated area is from the screen center of the deteriorated area A of the image frame 301 in the center of the screen where the deteriorated area is easily noticeable by the viewer. Is smaller than the distance t from the screen center of the degradation area B of the image frame 302 in the peripheral portion of the screen where the degradation area is difficult for the viewer to see. s becomes higher than the image quality degradation degree a / t of the image frame 302.

  When a plurality of degraded areas C and D exist in one image frame as in the image frame 303 of FIG. 3, the size of the degraded area C is c, the importance is 1 / u, and the degraded area D Since the size of the area is d and the importance is 1 / v, the image quality deterioration degree calculation unit 174 calculates the image quality deterioration degree of the image frame 303 as (c / u) + (d / v).

  Note that the image quality degradation degree calculation method is not limited to the method described in this embodiment. An arbitrary function using the value and importance included in the degraded area information as parameters may be used. As an example, the image quality deterioration degree calculation unit 174 may finally round the calculated image quality deterioration degree to an evaluation value of about five levels and output it.

  Next, the operation of this embodiment will be described in detail with reference to FIGS.

  In FIG. 1, when the video receiving terminal 100 starts receiving received data, the video receiving terminal 100 sequentially delivers the received data to the input data generating unit 130. When the input data generation unit 130 receives the reception data from the reception unit 120, the input data generation unit 130 sequentially generates the input data and stores it in the input data buffer 140. Also, the discontinuous position information generation unit 150 checks the input data, and if there is a discontinuous point, generates discontinuous position information and stores it in the discontinuous position information buffer 160.

  The video receiving terminal 100 continues the above operation until all the encoded image data is received. Hereinafter, it is assumed that input data and discontinuous position information are stored in the input data buffer 140 and the discontinuous position information buffer 160, respectively, and this embodiment is described with reference to the block diagram of FIG. 1 and the flowchart of FIG. The operation of the image quality evaluation unit 170A will be described in detail.

  First, the decoding processing unit 171 obtains a part of input data such as one frame or a predetermined amount among input data stored in the input data buffer 140 (step S11). .

  Next, the degradation region detection unit 172 obtains the discontinuity position information existing in the input data acquired in step S11 from the discontinuity position information buffer 160, for example, the address (number of bits) from the head of the data acquired in step S11. ) Or the like (step S12).

  Subsequently, the decoding processing unit 171 starts decoding the input data acquired in step S11 in units of macroblocks (step S13). At this time, the degradation region detection unit 172 determines whether or not the data being decoded includes a discontinuity point based on the discontinuity information acquired in step S12 (step S14).

  When the degradation region detection unit 172 determines that the data being decoded by the decoding processing unit 171 includes discontinuous points (Yes in step S14), the decoding processing unit 171 performs the next decoding processing on the acquired input data. Discard and skip to the synchronization position (step S15). Then, the deteriorated area detection unit 172 generates deteriorated area information from the information of the image area that could not be correctly decoded due to skipping the input data, and notifies the deteriorated area importance calculation unit 173 (step S16).

  Next, the decoding processing unit 171 decodes one image frame when the process of step S16 ends or when it is determined that the data decoded in step S14 does not include a discontinuous point (No in step S14). It is determined whether or not is completed (step S17).

  When the decoding of one image frame is completed, the decoding processing unit 171 outputs the decoded image frame to a display device (step S18). Further, the deteriorated area importance calculation unit 173 calculates the importance for each deteriorated area using the deteriorated area information from the deteriorated area detection unit 172, and the deteriorated area information and the importance are used as the image quality deterioration degree calculation unit 174. (Step S19). Subsequently, the image quality deterioration degree calculating unit 174 calculates the image quality deterioration degree of the frame based on the deterioration area information and the importance level notified in step S19, and outputs the calculated image quality deterioration degree to the outside (step). S20).

  On the other hand, the decoding processing unit 171 determines whether or not unprocessed input data remains when the processing of step S20 is completed or when it is determined in step S17 that decoding of one frame has not been completed (step S17). S21). If unprocessed input data remains, the decoding processing unit 171 proceeds to step S13 and continues the decoding process.

  If there is no unprocessed input data remaining, the decoding processing unit 171 determines whether the input data is at the end (step S22). If it is not the end of the input data, the process returns to step S11. In the case of the end of the input data, the processing of the image quality evaluation unit 170A ends.

  As described above, the image quality evaluation unit 170A of the present embodiment calculates the importance level of each degraded area for the degraded area that could not be decoded correctly, and calculates the image quality degradation level based on this importance. Compared with the case where the number of data samples that could not be simply added and the image quality deterioration degree calculated only from the size of the deteriorated area, the image quality deterioration degree closer to the subjective evaluation can be calculated.

(Second Embodiment)
Next, a second embodiment for carrying out the second invention of the present invention will be described in detail with reference to the drawings.

  FIG. 5 shows a block diagram of a second embodiment of the image quality evaluation apparatus according to the present invention. The image quality evaluation apparatus of the present embodiment is configured by replacing the image quality evaluation unit 170A of the first embodiment shown in FIG. 1 with an image quality evaluation unit 170B.

  The image quality evaluation unit 170 </ b> B includes a decoding processing unit 310, a degraded area importance level calculation unit 320, and an image quality degradation level calculation unit 330. The image quality deterioration degree calculation unit 330 is the same as the image quality deterioration degree calculation unit 174 of FIG.

  The decoding processing unit 310 includes a deteriorated region detection unit 311 and a region of interest detection unit 312. Compared with the decoding processing unit 171 in FIG. 1, the decoding processing unit 310 includes a deteriorated region detecting unit 311 having the same configuration as the deteriorated region detecting unit 172 in FIG. 1, but additionally includes a region of interest detecting unit 312. It is different in point. The region-of-interest detection unit 312 detects a region of interest on the image frame generated by decoding the input data by the decoding processing unit 310, and uses the detected region information as region-of-interest information to the degraded region importance calculation unit 320. Notice.

  The region of interest is a region where the viewer is likely to be interested in the image frame, such as a person's face, a moving ball or a sports player in a sports video, for example. When image quality deterioration occurs in such an area, the image quality feels worse than when image quality deterioration occurs in an area that the viewer is not interested in, such as the background portion of the video.

  As a method of detecting a region of interest, an image region where specific colors are dense may be detected as a region of interest. For example, it is possible to estimate a region where pixels having color information considered to be skin color are dense as a human face portion and detect it as a region of interest.

  In addition, an image area in which macroblocks having a large motion vector size or a small motion vector size compared to other image areas is dense may be detected as a region of interest. For example, in a video where an object such as a ball crosses against a stationary background, the size of the motion vector of the macroblock in the background portion is almost zero, whereas the size of the motion vector of the macroblock in the object portion is Therefore, the region of interest can be detected by detecting a region where macroblocks having a large motion vector are concentrated.

  In addition, an image region having a higher frequency component than other images may be detected as a region of interest. Further, when creating compressed image data in advance, the region of interest information may be generated and attached to the image data, and the region of interest may be detected based on this information.

  Note that the above method of detecting a region of interest is merely an example, and any method of detecting a region of interest may be used.

The region of interest information includes
(1) Location information of a region of interest expressed by a list of coordinates of pixels or macroblocks that constitute a region of interest, a list of coordinates of polygon vertices surrounding the region of interest, etc.
(2) Information indicating the video characteristics of the region of interest expressed by the average value of the color of the pixels in the region of interest, the average value of the motion vectors of the macroblocks in the region of interest, etc.
(3) Information representing the feature of the region of interest such as an identifier indicating the type of the region of interest such as a person, an object, or a character is included.

  As a specific example, in the example shown in FIG. 6, the region-of-interest detection unit 312 shows an area where flesh-colored pixels are dense from the image frame 601 shown in FIG. In this way, the region of interest 602 is detected, and a list of coordinate positions of macroblocks constituting the region of interest 602 is notified to the deteriorated region importance calculator 320 as region of interest information.

  The deteriorated region importance calculation unit 320 calculates the importance of the deteriorated region on the image from the deteriorated region information notified from the deteriorated region detection unit 311 and the region of interest information notified from the region of interest detection unit 312. The area information and importance level are notified to the image quality degradation level calculation unit 330.

  As an example, a method for calculating the importance from the positional relationship between the deteriorated region and the region of interest is shown.

  The degraded area importance calculation unit 320 receives from the degraded area detection unit 311 as degraded area information a list of the number of macroblocks that could not be decoded correctly due to data discontinuity and the coordinate position in the image frame of each macroblock, and A list of coordinate positions on the image frame of each macro block constituting the region of interest is received as region of interest information from the region of interest detection unit 312. The deteriorated area importance calculation unit 320 calculates the degree of importance of the overlapping of the respective coordinate positions indicated by the deteriorated area information and the interested area information. This is because when the image quality deterioration occurs in the region of interest, the image quality deterioration is more conspicuous than when the image quality deterioration occurs in a portion other than the region of interest.

  This will be described more specifically using the example shown in FIG. The degraded area importance calculation unit 320 includes degraded area information configured from a coordinate position list of macroblocks included in each of the degraded area E and the degraded area F in the image frame 601 notified from the degraded area detection unit 311; Compared with the region-of-interest information configured from the list of coordinates of the macroblocks constituting the region of interest 602 notified from the region-of-interest detector 312, the number of overlapping macroblocks is counted. Then, the degree of duplication is calculated by normalizing the total number of macroblocks with the total number of macroblocks included in each degradation region, and this is used as the importance. As shown in FIGS. 6A and 6B, the degraded area E has an importance of “0” because there is no macroblock overlapping the area of interest 602. The degree of importance of the degraded region F is “1” because the region of interest 602 and all macroblocks overlap. However, the importance calculation method is not limited to the one described in the above description.

  Next, the operation of this embodiment will be described in detail with reference to the block diagram of FIG. 5 and the flowchart of FIG. In the flowchart of FIG. 7, the same processing steps as those in the flowchart of FIG.

  5 and FIG. 7, when decoding of one image frame by the decoding processing unit 310 is completed (Yes in step S <b> 17), the region-of-interest detection unit 312 detects a region of interest in the image frame that has been decoded, and Area information is generated and notified to the deteriorated area importance calculator 320 (step S31). In addition, the decoding processing unit 310 outputs the decoded image frame to a display device or the like (step S32).

  The deteriorated region importance calculation unit 320 calculates importance for each deteriorated region based on the deteriorated region information notified from the deteriorated region detection unit 311 and the region of interest information detected in step S31, and calculates the deteriorated region information. The importance level is notified to the image quality degradation level calculation unit 330 (step S33).

  The image quality deterioration degree calculation unit 330 calculates the image quality deterioration degree of the frame using the deterioration area information and importance notified from the deterioration area importance degree calculation unit 320 in step S33, and information on the calculated image quality deterioration degree Is output to the outside (step S34).

  As described above, in the present embodiment, the importance level is calculated only from the degraded area information by detecting the interested area and calculating the importance level based on the interested area information and the degraded area information. Compared with the embodiment, it is possible to calculate a degree of image quality degradation closer to subjective evaluation.

(Third embodiment)
Next, a third embodiment for carrying out the third invention of the present invention will be described in detail with reference to the drawings.

  FIG. 8 shows a block diagram of a third embodiment of the image quality evaluation apparatus according to the present invention. The image quality evaluation apparatus of the present embodiment is configured by replacing the image quality evaluation unit 170A of the first embodiment shown in FIG. 1 with an image quality evaluation unit 170C. 8, the same components as those in FIGS. 1 and 5 are denoted by the same reference numerals, and the description thereof is omitted. The image quality evaluation unit 170C of the present embodiment illustrated in FIG. 8 includes a decoding processing unit 171, a deteriorated region importance calculation unit 320, an image quality deterioration degree calculation unit 330, and a region of interest detection unit 340.

  The image evaluation unit 170C illustrated in FIG. 8 is characterized in that the region of interest detection unit 340 is provided outside the decoding processing unit when compared with the image evaluation unit 170B illustrated in FIG. Thereby, the decoding process part 171 becomes the same structure as the decoding process part 171 shown in FIG. In addition, the region of interest detection unit 340 performs the same operation as the region of interest detection unit 312 in the decoding processing unit 310 in the image evaluation unit 170B illustrated in FIG.

  When the data for one image frame is output from the decoding processing unit 171, the region-of-interest detection unit 340 detects the region of interest by analyzing the data of the image frame, and sends it to the degraded region importance calculation unit 320. Notice.

(Fourth embodiment)
Next, an embodiment for carrying out the fourth invention of the present invention will be described in detail with reference to the drawings.

  FIG. 9 shows a block diagram of a fourth embodiment of the image quality evaluation apparatus according to the present invention. The image quality evaluation apparatus of the present embodiment is configured by replacing the image quality evaluation unit 170A of the first embodiment shown in FIG. 1 with an image quality evaluation unit 170D. In FIG. 9, the same components as those in FIG.

  As shown in FIG. 9, the image quality evaluation unit 170D of the present embodiment includes a decoding processing unit 350, a deteriorated region importance calculation unit 320, an image quality deterioration degree calculation unit 330, and a region of interest storage unit 360. The The region-of-interest information storage unit 360 stores region-of-interest information in one or several frames of image frames that have been decoded immediately before the image frame that is currently being decoded. The decoding processing unit 350 has the same configuration as that of the decoding processing unit 310 of the second embodiment, but includes a region of interest detection unit 351 whose operation is slightly different from that of the region of interest detection unit 312 of the second embodiment. .

  The region-of-interest detection unit 351 detects the region of interest on the image frame and notifies the degradation region importance calculation unit 320 in the same manner as the region-of-interest detection unit 312 in the second embodiment. The region-of-interest detection unit 351 determines whether the region of interest has been successfully detected, stores the region-of-interest information, and reads the region-of-interest information.

  When the region of interest detection is successful, the region-of-interest detection unit 351 stores the region-of-interest information regarding the detected region of interest in the region-of-interest storage unit 360, and notifies the region-of-interest information to the degraded region importance degree calculation unit 320.

  The region-of-interest detection unit 351 has lost a large amount of encoded image data due to data discontinuity, and the image is greatly distorted, or the data of the region of interest information included in the encoded image data has been lost. In some cases, the region of interest cannot be detected normally.

  When the region of interest is not successfully detected, the region-of-interest detection unit 351 reads the region-of-interest information in the image frame decoded immediately before from the region-of-interest storage unit 360, and uses the degraded region as an alternative to the region-of-interest information of the frame. The importance level calculation unit 320 is notified. In general, in an image, the contents of adjacent image frames are very similar, and therefore, information on the region of interest in the adjacent image frames is used as an alternative here.

  At this time, the region-of-interest detection unit 351 may notify the degradation region importance degree calculation unit 320 that the region of interest cannot be detected normally and the information is alternative region-of-interest information.

  In addition, when the content of the video is greatly changed due to a scene change or the like from the immediately preceding frame, the region of interest information of the immediately preceding image frame may not be used as a substitute for the region of interest information on the frame. Therefore, the region-of-interest detection unit 351 determines whether the region-of-interest information stored in the region-of-interest information storage unit 360 can be replaced as the region-of-interest information of the image frame, and only when the region-of-interest information is determined to be replaceable. The region-of-interest information stored in the region-of-interest storage unit 360 is notified to the deteriorated region importance level calculating unit 320. If the region of interest information is not replaceable, the fact that the region of interest has not been detected cannot be detected. It is good also as what notifies.

  A specific example is shown with reference to FIG. Assume that the decoding processing unit 350 sequentially decodes the image frame 1001 shown in FIG. 10A and the image frame 1002 shown in FIG. When the decoding of the image frame 1001 is completed, the region-of-interest detection unit 351 in FIG. 9 detects the region of interest in the image frame 1001 and determines whether the detection is successful. When the region of interest in the image frame 1001 is successfully detected, the region-of-interest information of the detected region of interest 1003 shown in FIG. Save to

  Next, when the decoding of the image frame 1002 is completed, the region-of-interest detection unit 351 detects the region of interest in the image frame 1002 and similarly determines the success or failure of the detection. If the degradation region G of the image frame 1002 shown in FIG. 10C is severely degraded and the region of interest 1004 cannot be detected normally as shown in FIG. 10D, the region of interest detection unit 351 is stored. The region-of-interest information of the region of interest 1003 detected in the immediately preceding image frame 1001 is read from the region-of-interest storage unit 360, and this is notified to the deteriorated region importance calculation unit 320. The deteriorated region importance calculation unit 320 calculates the importance of the deteriorated region G of the image frame 1002 based on the deteriorated region information of the deteriorated region G and the region of interest information of the image frame 1001.

  Next, the operation of this embodiment will be described in detail with reference to the block diagram of FIG. 9 and the flowchart of FIG. In FIG. 11, the same processing steps as those in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted.

  The decoding processing unit 350 of FIG. 9 determines whether or not the region of interest has been normally detected by the region of interest detection unit 351 after outputting the image frame that has been decoded to a display device (step S32) (step S41). If the region of interest can be detected normally (Yes in step S41), the detected region-of-interest information is notified to the deteriorated region importance calculation unit 320 and stored in the region of interest storage unit 360 (step S43), and step S44. Proceed to

  On the other hand, when the region of interest cannot be detected normally (No in step S41), the region-of-interest information of the region of interest detected in the immediately preceding image frame stored in the region of interest storage unit 360 is read and decoding is completed. As a substitute for the region-of-interest information of the image frame, the degradation region importance calculation unit 320 is notified (step S42).

  The deteriorated region importance calculation unit 320 stores the deteriorated region information notified from the deteriorated region detection unit 311 and the region of interest information normally detected in step S31 or the region of interest storage unit 360 read in step S42. Based on the region-of-interest information of the region of interest detected in the immediately preceding image frame, the importance for each deteriorated region is calculated, and the deteriorated region information and the calculated importance are notified to the image quality deterioration calculating unit 330. (Step S44).

  As described above, in the present embodiment, by storing the region-of-interest information of the image frame decoded immediately before, the image quality degradation degree is calculated even when the region of interest is severely detected and the region of interest cannot be detected. be able to.

  Note that the present invention is not limited to the above embodiment. For example, the image quality that causes the computer to execute the operation of any one of the image quality evaluation units 170A to 170D of the first to fourth embodiments. The evaluation program is also included in the present invention, and includes a video receiving terminal having the same configuration as that shown in FIG. 1 including any one of the image quality evaluating units 170A to 170D, and the video receiving terminal. An image quality distribution system in a video processing system including a video distribution server that distributes video data via a transmission path is also included in the present invention.

  The present invention can be used for management / monitoring of service quality by measuring video quality on a receiving terminal in a video distribution service.

1 is a block diagram of a video receiving terminal including a first embodiment of an image quality evaluation apparatus of the present invention. It is a figure explaining an example of operation | movement of the input data generation part 130 of FIG. It is a figure explaining operation | movement of the degradation area importance calculation part and image quality degradation degree calculation part in 1st Embodiment of the image quality evaluation apparatus of this invention. It is a flowchart for operation | movement description of embodiment of FIG. It is a block diagram of 2nd Embodiment of the image quality evaluation apparatus of this invention. It is a figure explaining operation | movement of the region of interest detection part in 2nd Embodiment of the image quality evaluation apparatus of this invention. It is a flowchart for operation | movement description of embodiment of FIG. It is a block diagram of 3rd Embodiment of the image quality evaluation apparatus of this invention. It is a block diagram of 4th Embodiment of the image quality evaluation apparatus of this invention. It is a figure explaining operation | movement of the region of interest detection part in 4th Embodiment of the image quality evaluation apparatus of this invention. It is a flowchart for operation | movement description of embodiment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Video receiving terminal 110 Transmission path 120 Receiving part 130 Input data generation part 140 Input data buffer 150 Discontinuous position information generation part 160 Discontinuous position information buffer 170A, 170B, 170C, 170D Image quality evaluation part 171, 310, 350 Decoding processing part 172, 311 Degraded region detection unit 173, 320 Degraded region importance calculation unit 174, 330 Image quality degradation degree calculation unit 312, 340, 351 Interest region detection unit 360 Interest region information storage unit

Claims (35)

When the encoded image data to be evaluated is received together with the discontinuous position information indicating the discontinuous position due to data loss or data error, the image encoded data is decoded to generate the image data. Based on continuous position information, an image encoded data portion between a discontinuous point in the image encoded data and a decoding process synchronization position that is a position that can be correctly decoded is specified, and the specified image encoded data A deteriorated area detecting means for detecting an affected image area as a deteriorated area;
Image quality deterioration degree calculating means for calculating an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on at least information on the deteriorated area indicating the characteristic of the deteriorated area detected by the deteriorated area detecting means. When,
An image quality evaluation apparatus comprising: A decoding processing unit that decodes encoded image data to be evaluated for image quality and generates an image frame;
When it is determined that the encoded image data to be decoded includes discontinuous points based on discontinuous position information indicating discontinuous positions due to data loss or data errors in the encoded image data, the discontinuous points And a decoding process synchronization position that is a position that can be correctly decoded is specified as an image encoded data part, an image area affected by the specified image encoded data part is detected as a deteriorated area, A deteriorated area detection unit that generates information of a deteriorated area indicating a feature;
A deterioration area importance calculation unit for calculating the importance of the deterioration area from the information of the deterioration area;
An image quality deterioration degree calculating unit that calculates an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on the information of the deteriorated area and the importance;
An image quality evaluation apparatus comprising: A decoding processing unit that decodes encoded image data to be evaluated for image quality and generates an image frame;
When it is determined that the encoded image data to be decoded includes discontinuous points based on discontinuous position information indicating discontinuous positions due to data loss or data errors in the encoded image data, the discontinuous points And a decoding process synchronization position that is a position that can be correctly decoded is specified as an image encoded data part, an image area affected by the specified image encoded data part is detected as a deteriorated area, A deteriorated area detection unit that generates information of a deteriorated area indicating a feature;
A region of interest that detects a region of interest indicating a region that is highly likely to be watched by a viewer from the image frame decoded by the decoding processing unit, and generates region-of-interest information indicating the characteristics of the region of interest. A detection unit;
A deteriorated region importance calculating unit that calculates the importance of the deteriorated region from the information of the deteriorated region and the region of interest information;
An image quality deterioration degree calculating unit that calculates an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on the information of the deteriorated area and the importance;
An image quality evaluation apparatus comprising:   The information of the deteriorated area includes (1) the number of blocks constituted by pixels or a plurality of pixels that could not be correctly decoded, (2) coordinate positions on the image frame of the blocks constituted by the pixels or the plurality of pixels, It includes one or more of (3) color information of a block composed of the pixel or a plurality of pixels, and (4) a magnitude of a motion vector of a block composed of the pixels or the plurality of pixels. The image quality evaluation apparatus according to any one of claims 1 to 3.   The degraded area importance calculation unit includes the pixel included in the degraded area information, or the coordinate position on the image frame of the constituent block by a plurality of pixels that could not be correctly decoded, from the center of the decoded image frame. 3. The image quality evaluation apparatus according to claim 2, wherein a distance to the deteriorated area is calculated, and importance is calculated based on the distance.   The region-of-interest detection unit includes (1) an image area where pixels having specific color information are densely arranged, and (2) a pixel or a plurality of pixels whose motion vectors are greatly different from the surrounding image areas. 2. The method according to claim 1, wherein any one or more of an image region in which the blocks formed are dense and (3) an image region having a higher frequency component compared to other image regions is detected as a region of interest. 3. The image quality evaluation apparatus according to 3.   The image quality evaluation apparatus according to claim 3, wherein the region-of-interest detection unit detects a region of interest based on region-of-interest information previously given to the encoded image data.   The region-of-interest information includes (1) coordinates of a block composed of a pixel or a plurality of pixels included in the region of interest, (2) a list of coordinates of vertices of a polygon surrounding the region of interest, and (3) the region of interest 1 out of the color information of the pixels included in the region, (4) the size of the motion vector of the pixel included in the region of interest or a block composed of a plurality of pixels, and (5) the identifier indicating the type of the region of interest The image quality evaluation apparatus according to claim 3, comprising at least two.   The image quality evaluation apparatus according to claim 3, wherein the deteriorated area importance calculation unit calculates the importance based on a degree of overlap of the deteriorated area and the region of interest in an image frame. A region of interest storage for storing the region of interest information;
The region-of-interest detection unit stores the generated region-of-interest information in the region-of-interest information storage unit when the region-of-interest detection is successful, and the region of interest when the region-of-interest detection fails. The image quality evaluation apparatus according to claim 3, wherein the region-of-interest information of the decoded image frame is generated based on the region-of-interest information stored in a storage unit.   When the region-of-interest information detection unit fails to detect the region of interest, the image frame that is stored in the region-of-interest information storage unit and is decoded immediately before the image frame that has failed to detect the region of interest The image quality evaluation apparatus according to claim 10, wherein the region-of-interest information of the decoded image frame is generated based on the region-of-interest information. The region of interest information detector
When the region of interest detection fails, the region-of-interest information of the image frame decoded immediately before the image frame that failed to detect the region of interest stored in the region-of-interest information storage unit is the region of interest. Determining means for determining whether or not it can be substituted as region-of-interest information of an image frame in which the detection of
Only when it is determined by the determination means that the region of interest can be replaced, the region-of-interest information of the image frame decoded immediately before the image frame that has failed to detect the region of interest that has been determined to be replaceable is sent to the degraded region importance calculation unit. A notification means for notifying the deterioration area importance calculation unit that the region-of-interest information has not been obtained,
The deterioration area importance calculation unit calculates the importance of the deterioration area from the information of the deterioration area and the area of interest information when the area of interest information is notified, and when the area of interest information is not notified, The image quality evaluation apparatus according to claim 10, wherein importance of the deteriorated area is calculated from information on the deteriorated area. When the encoded image data to be evaluated is received together with the discontinuous position information indicating the discontinuous position due to data loss or data error, the image encoded data is decoded to generate the image data. A first step of specifying an image encoded data portion between a discontinuous point in the image encoded data and a decoding processing synchronization position that is a position that can be correctly decoded based on continuous position information;
A second step of detecting an image area affected by the specified encoded image data as a degraded area;
A third step of calculating an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on at least information of the deteriorated area indicating the characteristic of the deteriorated area detected by the second step; ,
An image quality evaluation method comprising: A first step of decoding image encoded data to be evaluated for image quality and generating an image frame;
When it is determined that the encoded image data to be decoded includes discontinuous points based on discontinuous position information indicating discontinuous positions due to data loss or data errors in the encoded image data, the discontinuous points A second step of specifying an image encoded data portion between and a decoding process synchronization position that is a position where decoding can be correctly performed;
A third step of detecting an image area affected by the identified image encoded data portion as a deteriorated area, and generating information on the deteriorated area indicating characteristics of the deteriorated area;
A fourth step of calculating the degree of importance of the deteriorated area from the information of the deteriorated area;
A fifth step of calculating an image quality degradation level indicating an index of conspicuousness of image quality degradation due to the degraded area based on the information on the degraded area and the importance;
An image quality evaluation method comprising: A first step of decoding image encoded data to be evaluated for image quality and generating an image frame;
When it is determined that the encoded image data to be decoded includes discontinuous points based on discontinuous position information indicating discontinuous positions due to data loss or data errors in the encoded image data, the discontinuous points A second step of specifying an image encoded data portion between and a decoding process synchronization position that is a position where decoding can be correctly performed;
A third step of detecting an image area affected by the identified image encoded data portion as a deteriorated area, and generating information on the deteriorated area indicating characteristics of the deteriorated area;
First, a region of interest indicating a region that is likely to be watched with interest by the viewer is detected from the image frame decoded in the first step, and region-of-interest information indicating a feature of the region of interest is generated. 4 steps,
A fifth step of calculating the degree of importance of the deteriorated region from the information of the deteriorated region and the region of interest information;
A sixth step of calculating an image quality degradation degree indicating an index of conspicuousness of image quality degradation due to the degraded area based on the information of the degraded area and the importance;
An image quality evaluation method comprising:     The information of the deteriorated area includes (1) the number of blocks constituted by pixels or a plurality of pixels that could not be correctly decoded, (2) coordinate positions on the image frame of the blocks constituted by the pixels or the plurality of pixels, It includes one or more of (3) color information of a block composed of the pixel or a plurality of pixels, and (4) a magnitude of a motion vector of a block composed of the pixels or the plurality of pixels. The image quality evaluation method according to any one of claims 13 to 15.   In the fourth step, the deteriorated region from the center of the decoded image frame based on the coordinate position on the image frame of the constituent block by the pixel or the plurality of pixels that could not be correctly decoded included in the information of the deteriorated region The image quality evaluation method according to claim 14, further comprising calculating a distance up to and calculating importance based on the distance.   The fourth step includes (1) an image area where pixels having specific color information are densely packed, and (2) a pixel or a plurality of pixels whose motion vectors are greatly different from the surrounding image area. 2. The method according to claim 1, wherein any one or more of an image region in which the blocks formed are dense and (3) an image region having a higher frequency component compared to other image regions is detected as a region of interest. 15. The image quality evaluation method according to 15.   16. The image quality evaluation method according to claim 15, wherein the fourth step detects a region of interest based on region-of-interest information previously given to the encoded image data.   The region-of-interest information includes (1) coordinates of a block composed of a pixel or a plurality of pixels included in the region of interest, (2) a list of coordinates of vertices of a polygon surrounding the region of interest, and (3) the region of interest 1 out of the color information of the pixels included in the region, (4) the size of the motion vector of the pixel included in the region of interest or a block composed of a plurality of pixels, and (5) the identifier indicating the type of the region of interest The image quality evaluation method according to claim 15, comprising at least two.   16. The image quality evaluation method according to claim 15, wherein in the fourth step, the importance is calculated based on a degree in which the deteriorated region and the region of interest overlap in an image frame. A seventh step of storing the region-of-interest information generated in the fourth step in a region-of-interest information storage unit;
If the region of interest fails to be detected in the fourth step, the region of interest information of the decoded image frame is generated based on the region of interest information stored in the region of interest storage. The image quality evaluation method according to claim 15, further comprising:   In the eighth step, the decoded image frame based on the region-of-interest information of the image frame that is stored in the region-of-interest information storage unit and is decoded immediately before the image frame in which the region-of-interest detection has failed. 23. The image quality evaluation method according to claim 22, wherein the region-of-interest information is generated. The eighth step includes
The region-of-interest information stored in the region-of-interest information storage unit is the region-of-interest information of the image frame decoded immediately before the image frame in which the region-of-interest detection failed, as region-of-interest information of the image frame in which the region-of-interest detection failed. A determination step for determining whether or not substitution is possible; and
Only when it is determined that it can be replaced by the determination step, the region-of-interest information of the image frame decoded immediately before the image frame in which the detection of the region of interest that has been determined to be replaceable has failed is sent to the degraded region importance calculation unit. A notification step of notifying the deterioration area importance calculation unit that the region-of-interest information has not been obtained,
In the fifth step, when the region of interest information is notified, the importance of the deteriorated region is calculated from the information of the deteriorated region and the region of interest information, and when the region of interest information is not notified, the deteriorated region is calculated. 24. The image quality evaluation method according to claim 23, wherein the degree of importance of the deteriorated area is calculated from the information. An image quality evaluation program for evaluating the image quality of an image frame obtained by decoding image encoded data by a computer,
In the computer,
The image encoded data is received as an input together with discontinuous position information indicating a discontinuous position due to data loss or data error, and the image encoded data is decoded to generate image data. A first step of specifying an image encoded data portion between a discontinuous point in the image encoded data and a decoding processing synchronization position that is a position where the image can be correctly decoded;
A second step of detecting an image area affected by the specified encoded image data as a degraded area;
A third step of calculating an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on at least information of the deteriorated area indicating the characteristic of the deteriorated area detected by the second step; ,
An image quality evaluation program characterized in that the program is executed. An image quality evaluation program for evaluating the image quality of an image frame obtained by decoding image encoded data by a computer,
In the computer,
A first step of decoding image encoded data to be evaluated for image quality and generating an image frame;
When it is determined that the encoded image data to be decoded includes discontinuous points based on discontinuous position information indicating discontinuous positions due to data loss or data errors in the encoded image data, the discontinuous points A second step of specifying an image encoded data portion between and a decoding process synchronization position that is a position where decoding can be correctly performed;
A third step of detecting an image area affected by the identified image encoded data portion as a deteriorated area, and generating information on the deteriorated area indicating characteristics of the deteriorated area;
A fourth step of calculating the degree of importance of the deteriorated area from the information of the deteriorated area;
A fifth step of calculating an image quality degradation level indicating an index of conspicuousness of image quality degradation due to the degraded area based on the information on the degraded area and the importance;
An image quality evaluation program characterized in that the program is executed. An image quality evaluation program for evaluating the image quality of an image frame obtained by decoding image encoded data by a computer,
In the computer,
A first step of decoding image encoded data to be evaluated for image quality and generating an image frame;
When it is determined that the encoded image data to be decoded includes discontinuous points based on discontinuous position information indicating discontinuous positions due to data loss or data errors in the encoded image data, the discontinuous points A second step of specifying an image encoded data portion between and a decoding process synchronization position that is a position where decoding can be correctly performed;
A third step of detecting an image area affected by the identified image encoded data portion as a deteriorated area, and generating information on the deteriorated area indicating characteristics of the deteriorated area;
First, a region of interest indicating a region that is likely to be watched with interest by the viewer is detected from the image frame decoded in the first step, and region-of-interest information indicating a feature of the region of interest is generated. 4 steps,
A fifth step of calculating the degree of importance of the deteriorated region from the information of the deteriorated region and the region of interest information;
A sixth step of calculating an image quality degradation degree indicating an index of conspicuousness of image quality degradation due to the degraded area based on the information of the degraded area and the importance;
An image quality evaluation program characterized in that the program is executed.   The information of the deteriorated area includes (1) the number of blocks constituted by pixels or a plurality of pixels that could not be correctly decoded, (2) coordinate positions on the image frame of the blocks constituted by the pixels or the plurality of pixels, It includes one or more of (3) color information of a block composed of the pixel or a plurality of pixels, and (4) a magnitude of a motion vector of a block composed of the pixels or the plurality of pixels. The image quality evaluation program according to any one of claims 25 to 27.   In the fourth step, the deteriorated region from the center of the decoded image frame based on the coordinate position on the image frame of the constituent block by the pixel or the plurality of pixels that could not be correctly decoded included in the information of the deteriorated region 27. The image quality evaluation program according to claim 26, further comprising: calculating a distance up to and calculating importance based on the distance.   The fourth step includes (1) an image area where pixels having specific color information are densely packed, and (2) a pixel or a plurality of pixels whose motion vectors are greatly different from the surrounding image area. 2. The method according to claim 1, wherein any one or more of an image region in which the blocks formed are dense and (3) an image region having a higher frequency component compared to other image regions is detected as a region of interest. 27. The image quality evaluation program according to 27.   The region-of-interest information includes (1) coordinates of a block composed of a pixel or a plurality of pixels included in the region of interest, (2) a list of coordinates of vertices of a polygon surrounding the region of interest, and (3) the region of interest 1 out of the color information of the pixels included in the region, (4) the size of the motion vector of the pixel included in the region of interest or a block composed of a plurality of pixels, and (5) the identifier indicating the type of the region of interest 28. The image quality evaluation program according to claim 27, comprising at least two. A seventh step of storing the region-of-interest information generated in the fourth step in a region-of-interest information storage unit;
If the region of interest fails to be detected in the fourth step, the region of interest information of the decoded image frame is generated based on the region of interest information stored in the region of interest storage. And the steps
28. The image quality evaluation program according to claim 27, further comprising: A video receiving terminal that receives data including image encoded data to be evaluated for image quality as an input from a video distribution server via a transmission path, and performs reception processing;
An input data generation unit that receives the data input via the transmission path and generates the image encoded data;
A discontinuous information generating unit that detects a discontinuous point due to data loss or data error in the image encoded data, and generates discontinuous position information indicating the position of the discontinuous point in the image encoded data;
An image quality evaluation unit that receives the encoded image data and the discontinuous position information as input, and calculates an image quality degradation degree of an image frame obtained by decoding the encoded image data;
And the image quality evaluation unit
When generating the image data by decoding the image encoded data, based on the discontinuous position information, a position from the discontinuous point in the image encoded data to a decoding process synchronization position that is a correct decodable position is determined. A degraded area detecting means for identifying an image encoded data portion between and detecting an image area affected by the identified image encoded data as a degraded area;
Image quality deterioration degree calculating means for calculating an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on at least information on the deteriorated area indicating the characteristic of the deteriorated area detected by the deteriorated area detecting means. When,
A video receiving terminal characterized by comprising: A video receiving terminal that receives data including image encoded data to be evaluated for image quality as an input from a video distribution server via a transmission path, and performs reception processing;
An input data generation unit that receives the data input via the transmission path and generates the image encoded data;
A discontinuous information generating unit that detects a discontinuous point due to data loss or data error in the image encoded data, and generates discontinuous position information indicating the position of the discontinuous point in the image encoded data;
An image quality evaluation unit that receives the encoded image data and the discontinuous position information as input, and calculates an image quality degradation degree of an image frame obtained by decoding the encoded image data;
And the image quality evaluation unit
A decoding processor that decodes the encoded image data and generates an image frame;
Based on the discontinuous position information, when it is determined that the encoded image data to be decoded includes a discontinuous point, a distance between the discontinuous point and a decoding processing synchronization position that is a position that can be correctly decoded A deteriorated area detecting unit that identifies an image encoded data part, detects an image area affected by the specified image encoded data part as a deteriorated area, and generates information on a deteriorated area indicating characteristics of the deteriorated area;
A deterioration area importance calculation unit for calculating the importance of the deterioration area from the information of the deterioration area;
An image quality deterioration degree calculating unit that calculates an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on the information of the deteriorated area and the importance;
A video receiving terminal characterized by comprising: A video receiving terminal that receives data including image encoded data to be evaluated for image quality as an input from a video distribution server via a transmission path, and performs reception processing;
An input data generation unit that receives the data input via the transmission path and generates the image encoded data;
A discontinuous information generating unit that detects a discontinuous point due to data loss or data error in the image encoded data, and generates discontinuous position information indicating the position of the discontinuous point in the image encoded data;
An image quality evaluation unit that receives the encoded image data and the discontinuous position information as input, and calculates an image quality degradation degree of an image frame obtained by decoding the encoded image data;
And the image quality evaluation unit
A decoding processor that decodes the encoded image data and generates an image frame;
When it is determined that the encoded image data to be decoded includes a discontinuous point based on discontinuous position information indicating the discontinuous position of the encoded image data, a position that can be correctly decoded from the discontinuous point The encoded image data portion up to the decoding processing synchronization position is identified, an image region affected by the identified image encoded data portion is detected as a deteriorated region, and the deteriorated region indicating the characteristics of the deteriorated region A deteriorated area detector that generates information;
A region of interest that detects a region of interest indicating a region that is highly likely to be watched by a viewer from the image frame decoded by the decoding processing unit, and generates region-of-interest information indicating the characteristics of the region of interest. A detection unit;
A deteriorated region importance calculating unit that calculates the importance of the deteriorated region from the information of the deteriorated region and the region of interest information;
An image quality deterioration degree calculating unit that calculates an image quality deterioration degree indicating an index of conspicuousness of image quality deterioration due to the deteriorated area based on the information of the deteriorated area and the importance;
A video receiving terminal characterized by comprising: