Information Processing Apparatus, Pulse Wave Calculation Method, and Program

Abstract

To provide an information processing device capable of inhibiting noise from being included in a pulse wave signal attributed to the movement of a living body.SOLUTION: On an image of each frame constituting a moving image taken of a living body, an information processing device includes: a region-of-interest setting unit for setting the position of a region of interest; a pixel value calculation unit for calculating a plurality of first representative values of a pixel value of a pixel in the set positions of a plurality of regions of interest for a plurality of images of a second frame including images of a first frame in the images of the first frame constituting the moving image; a pixel value synthesizing unit for synthesizing the plurality of first representative values and calculating a second representative value for the first frame; and a pulse wave calculation unit for calculating a pulse wave signal from a temporal change in the second representative value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an information processing apparatus, a pulse wave calculation method, and a program.

Background Art

[0002] Patent Document 1 discloses a technique for calculating a pulse wave from a video of a human face. When calculating the pulse wave, the face is detected in each frame of the video, noise sources that reduce the pulse wave accuracy are identified, a region of interest and sub-regions obtained by dividing the region of interest are set, and the pulse wave signals calculated for each sub-region are weighted using the information on the noise sources to form a noise-suppressed pulse wave signal. In the technique disclosed in Patent Document 1, when it is determined that a rigid body motion or a non-rigid body motion has occurred, the rigid body motion or the non-rigid body motion is identified as a noise source, and the pulse wave is calculated without using the pixels in the moving part within the region of interest.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique disclosed in Patent Document 1, when it is determined that the living body as the imaging object has moved and a rigid body motion or a non-rigid body motion has occurred, the number of pixels used within the region of interest is reduced compared to the case where the living body has not moved. When the number of pixels within the region of interest used for calculating the pulse wave decreases, the signal-to-noise ratio decreases, so there is a risk of an increase in noise in the entire data. Further, in the technique disclosed in Patent Document 1, since the number of pixels within the region of interest changes depending on whether the living body has moved or not, there is a risk that noise is included in the calculated pulse wave signal. Therefore, an aspect of the present disclosure aims to provide an information processing apparatus, a pulse wave calculation method, and a program that can suppress the inclusion of noise in the pulse wave signal due to the movement of the living body.

Means for Solving the Problem

[0005] An information processing apparatus according to an aspect of the present disclosure includes a region of interest setting unit that sets the position of a region of interest for each frame image constituting a moving image obtained by imaging a living body, and in the image of the first frame constituting the moving image, a pixel value calculation unit that calculates a plurality of first representative values of pixel values of pixels at the positions of a plurality of regions of interest set for a plurality of second frame images including the image of the first frame, a pixel value synthesis unit that synthesizes the plurality of first representative values to calculate a second representative value for the first frame, and a pulse wave calculation unit that calculates a pulse wave signal from the temporal change of the second representative value.

[0006] A pulse wave calculation method according to an aspect of the present disclosure includes a step of setting the position of a region of interest for each frame image constituting a moving image obtained by imaging a living body, a step of calculating a plurality of first representative values of pixel values of pixels at the positions of a plurality of regions of interest set for a plurality of second frame images including the image of the first frame in the image of the first frame constituting the moving image, a step of synthesizing the plurality of first representative values to calculate a second representative value for the first frame, and a step of calculating a pulse wave signal from the temporal change of the second representative value.

[0007] A program according to an aspect of the present disclosure causes a computer to execute a function of setting the position of a region of interest for each frame image constituting a moving image obtained by imaging a living body, a function of calculating a plurality of first representative values of pixel values of pixels at the positions of a plurality of regions of interest set for a plurality of second frame images including the image of the first frame in the image of the first frame constituting the moving image, a function of synthesizing the plurality of first representative values to calculate a second representative value for the first frame, and a function of calculating a pulse wave signal from the temporal change of the second representative value.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0009] (First Embodiment) Referring to FIGS. 1 to 6, the first embodiment will be described. Note that, in the drawings, the same or similar elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] FIG. 1 is a diagram showing an example of the usage mode of the information processing apparatus 100. As illustrated in FIG. 1, the information processing apparatus 100 includes an imaging unit 101.

[0011] The information processing apparatus 100 calculates a pulse wave signal indicating a pulse wave from an image acquired by the imaging unit 101. For example, the information processing apparatus 100 is a PC (Personal Computer), a smartphone, a tablet terminal, a dedicated pulse wave measurement terminal, or the like. In this specification, the pulse wave is a time-series signal indicating a change in the volume of blood vessels, which is calculated from a time-series signal indicating the pixel values of the pixels included in the image, with respect to the same position on the body surface. In this specification, the pixel value is information indicating the brightness of the pixel included in the image, and is, for example, the pixel value of each pixel of R (Red), G (Green), B (Blue) or the luminance value of the pixel.

[0012] The imaging unit 101 images the living body 102 and acquires a moving image 211 (see FIG. 2). The moving image 211 includes an image of the body surface of the living body 102. For example, the imaging unit 101 is composed of a CCD (Charged Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The imaging unit 101 may be composed of an image sensor for a camera including an RGB filter.

[0013] FIG. 2 is a block diagram showing an example of the configuration of the information processing apparatus 100 according to the present embodiment. The information processing apparatus 100 includes an imaging unit 101, a storage unit 201, and a control unit 202.

[0014] The imaging unit 101 images the living body 102 and acquires a moving image 211.

[0015] The storage unit 201 is a recording medium capable of recording various data, programs, etc., and is composed of, for example, a hard disk, an SSD (Solid State Drive), a semiconductor memory, or the like.

[0016] The control unit 202 executes various processes according to the programs and data stored in the storage unit 201. The control unit 202 is realized by a processor such as a CPU (Central Processing Unit), for example.

[0017] The control unit 202 includes an interested region setting unit 203, a pixel value calculation unit 204, a pixel value synthesis unit 205, and a pulse wave calculation unit 206.

[0018] The interested region setting unit 203 sets the position of the interested region for each frame image constituting the moving image 211. The interested region is set in the image of the body surface. For example, the image of the body surface is an image of the face, an image of the cheek, an image of the forehead, an image of the palm, an image of the wrist, an image of the sole of the foot, etc. Then, the interested region setting unit 203 outputs a set of interested region information 212 and identification information 213 to the pixel value calculation unit 204 for each frame image constituting the moving image 211. The interested region information 212 indicates the coordinates indicating the interested region for each frame image constituting the moving image 211. The identification information 213 is information for identifying the frame in which the interested region is set.

[0019] The pixel value calculation unit 204 calculates a plurality of first representative values 214 of the pixel values of the pixels at the positions of the plurality of interested regions set for a plurality of second frame images including the image of the first frame in the image of the first frame constituting the moving image 211. When a plurality of second frames are selected for the first frame, the pixel value calculation unit 204 outputs a set of the plurality of first representative values 214 and the plurality of identification information 215 to the pixel value synthesis unit 205. The plurality of identification information 215 is information for identifying the first frame and the plurality of second frames.

[0020] When a plurality of second frames are not selected for the first frame, the pixel value calculation unit 204 calculates the representative value of the pixel value of the pixel at the position of the interested region set for the image of the first frame as the second representative value 216. When a plurality of second frames are not selected for the first frame, the pixel value calculation unit 204 outputs a set of the second representative value 216 and the identification information 217 to the pulse wave calculation unit 206. The identification information 217 is information for identifying the first frame.

[0021] The pixel value synthesizing unit 205 synthesizes a plurality of first representative values 214 to calculate a second representative value 216 for the first frame. The pixel value synthesizing unit 205 outputs a pair of the second representative value 216 and the identification information 217 to the pulse wave calculating unit 206.

[0022] The pulse wave calculating unit 206 calculates a pulse wave signal from the temporal change of the second representative value 216.

[0023] FIG. 3 is a flowchart showing an example of the operation of the information processing apparatus 100 according to the present embodiment.

[0024] In step S301, the imaging unit 101 images the living body 102 to acquire a moving image 211. The imaging unit 101 outputs the image of each frame constituting the acquired moving image 211 to the region of interest setting unit 203 and the pixel value calculating unit 204. Note that the information processing apparatus 100 may acquire the moving image 211 from a device different from the imaging unit 101. That is, a device different from the imaging unit 101 may image the living body 102 to acquire the moving image 211. Then, the device different from the imaging unit 101 may transmit the acquired moving image 211 to the information processing apparatus 100.

[0025] In step S302, the region of interest setting unit 203 sets the position of the region of interest for the image of each frame constituting the moving image 211. Then, the region of interest setting unit 203 outputs a pair of the region of interest information 212 and the identification information 213 to the pixel value calculating unit 204 for the image of each frame constituting the moving image 211. For example, the identification information 213 indicates the serial number of each frame constituting the moving image 211. Alternatively, the identification information 213 may indicate the elapsed time from when the imaging unit 101 starts the imaging process for the time when each frame constituting the moving image 211 is acquired. Alternatively, the identification information 213 may indicate the time when each frame constituting the moving image 211 is acquired.

[0026] For example, when the face image is included in the image of the frame constituting the moving image 211, the region of interest setting unit 203 determines whether the face image is included in the image of the frame constituting the moving image 211 by detecting feature points such as eyes, nose, and mouth. For example, assume that the region of interest setting unit 203 sets the region of the cheek image as the region of interest. In that case, when the cheek image is included in the image of the frame constituting the moving image 211, the region of interest setting unit 203 sets the region of interest at the position of the detected cheek image.

[0027] For example, the region of interest setting unit 203 sets the position of the region of interest by detecting the cheek image for each image of the frames constituting the moving image 211. Alternatively, when the region of interest setting unit 203 sets the region of interest for the image of one frame constituting the moving image 211, for the images of the frames after the one frame, the region of interest may be tracked by an object tracking technique to set the position of the region of interest.

[0028] For example, the shape of the region of interest may be a polygon surrounded by straight lines or a shape surrounded by curves. Alternatively, the shape of the region of interest may be a shape determined according to the shape of the living body part. For example, when the region of interest setting unit 203 sets the region of interest as a polygon, the region of interest information 212 indicates the coordinates of the vertices of the polygon indicating the region of interest. Also, for example, when the region of interest setting unit 203 sets the region of interest as a circle, the region of interest information 212 indicates the coordinates of the center of the circle indicating the region of interest and the length of the radius indicating the region of interest.

[0029] Alternatively, the region of interest information 212 may indicate a logical value matrix for each image of the frames constituting the moving image 211. The logical value matrix indicated by the region of interest information 212 indicates whether each pixel included in the image is included in the region of interest. That is, the logical value matrix indicated by the region of interest information 212 is a matrix of the same size as the image of the frame constituting the moving image and indicates the position of the region of interest.

[0030] In step S303, the pixel value calculation unit 204 selects the first frame in chronological order from a plurality of frames constituting the moving image 211.

[0031] In step S304, the pixel value calculation unit 204 determines whether it is possible to select a plurality of second frames including the first frame selected in step S303 from a plurality of frames constituting the moving image 211. Here, it is assumed that the plurality of second frames include the image of the first frame and represent a plurality of images captured within a predetermined time. In that case, the pixel value calculation unit 204 determines whether it is possible to select the images of a plurality of frames including the image of the first frame and captured within a predetermined time.

[0032] Or, it is assumed that the images of the plurality of second frames include the image of the first frame and represent a plurality of continuously captured images as the images of the plurality of second frames. In that case, the pixel value calculation unit 204 determines whether it is possible to select the images of a plurality of frames including the image of the first frame and continuously captured within a predetermined time.

[0033] Also, for example, it is assumed that the images of the plurality of second frames include the image of the first frame and the image of at least one frame captured before the first frame. And it is assumed that the first frame represents the image of the first captured frame among the images of the plurality of frames constituting the moving image 211. In that case, the pixel value calculation unit 204 cannot select a plurality of second frames from the plurality of frames constituting the moving image 211.

[0034] Also, for example, it is assumed that the images of the plurality of second frames include the image of the first frame and the image of at least one frame captured after the first frame. And it is assumed that the first frame represents the image of the last captured frame among the images of the plurality of frames constituting the moving image 211. In that case, the pixel value calculation unit 204 cannot select a plurality of second frames including the first frame from the plurality of frames constituting the moving image 211.

[0035] If a plurality of second frames cannot be selected in step S304, in step S305, the pixel value calculation unit 204 calculates a second representative value 216 of the pixel values of the pixels at the positions of the regions of interest set in the image of the first frame in the image of the first frame. For example, when the imaging unit 101 is composed of an image sensor for a camera including an RGB filter, in step S305, the pixel value calculation unit 204 calculates a second representative value 216 of the pixel values for each of the R, G, and B pixels in the image of the first frame. Then, the pixel value calculation unit 204 outputs a pair of the second representative value 216 and the identification information 217 to the pulse wave calculation unit 206. The identification information 217 is information for identifying the first frame. The second representative value 216 is the average value, median value, maximum value, minimum value, etc. of the pixel values of each pixel in the region of interest.

[0036] On the other hand, if a plurality of second frames can be selected in step S304, in step S306, the pixel value calculation unit 204 calculates a plurality of first representative values 214 of the pixel values of the pixels at the positions of the plurality of regions of interest set in the images of the plurality of second frames in the image of the first frame.

[0037] For example, when the imaging unit 101 is composed of an image sensor for a camera including an RGB filter, in step S306, the pixel value calculation unit 204 calculates a plurality of first representative values 214 for each of the R, G, and B pixels at the positions of the plurality of regions of interest set in the images of the plurality of second frames in the image of the first frame. For example, assume that the number of frames of the second frame is 10 frames. In that case, in the image of the first frame, 10 regions of interest set in the 10 frames of images of the second frame are set. Then, the pixel value calculation unit 204 calculates 10 first representative values 214 from the pixel values of the pixels at the positions of the 10 set regions of interest for each of the R, G, and B pixels. Then, the pixel value calculation unit 204 outputs a pair of the plurality of first representative values 214 and the identification information 215 to the pixel value synthesis unit 205. The identification information 215 is information for identifying the first frame and the plurality of second frames.

[0038] In step S307, the pixel value synthesizing unit 205 synthesizes a plurality of first representative values 214 calculated in the image of the same first frame, and calculates a second representative value 216 for the first frame. The second representative value 216 calculated in step S307 is the average value, median value, maximum value, minimum value, etc. of the plurality of first representative values 214.

[0039] For example, when the imaging unit 101 is configured by an image sensor for a camera including an RGB filter, in step S307, the pixel value synthesizing unit 205 calculates a second representative value 216 of the pixel values for each of the R, G, and B pixels in the image of the first frame. For example, when the number of frames of the second frame is 10 frames, the pixel value calculating unit 204 calculates 10 first representative values 214 for each of the R, G, and B pixels. In that case, the pixel value synthesizing unit 205 synthesizes the 10 calculated first representative values 214 for each of the R, G, and B pixels to calculate the second representative value 216. Alternatively, the pixel value synthesizing unit 205 may weight each of the plurality of first representative values 214 and synthesize the weighted plurality of first representative values 214 to calculate the second representative value 216.

[0040] In step S308, the pixel value calculating unit 204 determines whether each frame constituting the moving image 211 is selected as the first frame. If each frame constituting the moving image 211 is not selected as the first frame in step S308, the control unit 202 returns the process to step S303. On the other hand, if each frame constituting the moving image 211 is selected as the first frame in step S308, the control unit 202 shifts the process to step S309.

[0041] In step S309, the pulse wave calculating unit 206 calculates a pulse wave signal from the time change of the second representative value 216. Specifically, the pulse wave calculating unit 206 calculates a pulse wave signal from the time change of the second representative value 216. For example, the pulse wave calculating unit 206 processes a signal indicating the time change of the second representative value 216 by multivariate analysis such as principal component analysis or independent component analysis, and calculates the processed result as a pulse wave signal.

[0042] For example, when the pixel value synthesizing unit 205 synthesizes a plurality of first representative values 214 for each of the R, G, and B pixels to calculate a second representative value 216, the pulse wave calculating unit 206 calculates a time series signal of the second representative value 216 for each of the R, G, and B pixels. That is, when the pixel value synthesizing unit 205 calculates the second representative value 216 for each of the R, G, and B pixels, the pulse wave calculating unit 206 calculates three time series signals indicating the time change of the second representative value 216. Then, the pulse wave calculating unit 206 calculates a pulse wave signal from the three calculated time series signals.

[0043] For example, assume that the pixel value calculating unit 204 selects the image Ft of the first frame and at least one image of a frame captured before the first frame as images of a plurality of second frames. In that case, in step S309, the pulse wave calculating unit 206 uses the second representative value 216 calculated in step S304 for the image of the first frame, which is the first captured frame among the images of the plurality of frames constituting the moving image 211, and uses the second representative value 216 calculated in step S307 for the images of the frames after the second frame.

[0044] FIG. 4A shows an example of the positions of the regions of interest 400 to 404 in each of five second-frame images from the (f - 4)-th frame to the f-th frame. FIG. 4B shows an example of the positions of the regions of interest 400 to 404 exemplified in FIG. 4A in the image of the first frame, which is the f-th frame.

[0045] For example, assume that the region of interest 400 set in the image of the f - 4th frame is rectangular. And in the region of interest 400, assume that the coordinates P1 of the upper - left vertex are (x1, y1) and the coordinates P2 of the lower - right vertex are (x2, y2). In that case, the pixel - value calculation unit 204 calculates the first representative value 214 of the pixel values of the pixels at the position of the rectangular region of interest in the image of the f - th frame, where the coordinates P1 of the upper - left vertex are (x1, y1) and the coordinates P2 of the lower - right vertex are (x2, y2). Similarly, four first representative values 214 of the pixel values of the pixels at the positions of the regions of interest 401 to 404 set from the f - 3rd frame to the f - th frame are calculated. Then, the pixel - value synthesis unit 205 calculates the second representative value 216 of the five first representative values 214 of the pixel values of the pixels at the positions of the regions of interest 400 to 404.

[0046] FIG. 5 is a diagram showing an example of a time - series signal 501 indicating the temporal change of the second representative value 216. Further, as a comparative example, FIG. 5 shows an example of a time - series signal 502 indicating the temporal change of the representative value of the pixel values of the pixels at the positions of the regions of interest set in the images of the respective frames constituting the moving image.

[0047] For example, assume that due to a slight movement of the living body 102, the position of the region of interest has moved by one pixel from the position of the region of interest set in the immediately preceding frame. In that case, when the position of the region of interest moves by one pixel, the distribution of the pixel values of the pixels included in the region of interest can change abruptly. When the distribution of the pixel values of the pixels included in the region of interest changes abruptly, as exemplified in the period T503 in the time - series signal 502, the representative value of the pixel values of the pixels at the position of the region of interest changes abruptly.

[0048] On the other hand, in the time - series signal 501, in the period T503, the change in the second representative value 216 is gentler than that in the time - series signal 502. That is, the information processing apparatus 100 can suppress the abrupt change in the representative value of the pixel values.

[0049] FIG. 6 is a diagram showing an example of a pulse wave signal 601 calculated from the time series signal 501 illustrated in FIG. 5. Further, FIG. 6 shows, as a comparative example, an example of a pulse wave signal 602 calculated from the time series signal 502 illustrated in FIG. 5. A period T603 illustrated in FIG. 6 is the same period as a period T503 illustrated in FIG. 5.

[0050] A rapid change in the representative value of the pixel values of the pixels at the position of the region of interest may cause noise in the pulse wave signal calculated from the time change of the representative value. For example, when the representative value of the pixel values of the pixels at the position of the region of interest changes rapidly as illustrated in the period T503 in the time series signal 502, the pulse wave signal 602 in the period T603 shows a more rapid change than the pulse wave signal 601 in the period T603. On the other hand, the information processing apparatus 100 calculates a pulse wave signal from the time change of a second representative value 216 calculated by synthesizing a plurality of first representative values 214. Thereby, the information processing apparatus 100 can suppress noise from being included in the calculated pulse wave signal due to fluctuations in the pixel values of the pixels within the region of interest caused by a slight movement of the living body 102.

[0051] (Second Embodiment) The second embodiment will be described with reference to FIGS. 7 to 9. Regarding the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted. Configurations and processes having substantially the same functions as those of other embodiments are referred to by the same reference numerals, and the descriptions thereof are omitted, and differences from other embodiments will be described.

[0052] FIG. 7 is a block diagram showing an example of the configuration of the information processing apparatus 100 according to the present embodiment. The difference between the information processing apparatus 100 illustrated in FIG. 7 and the information processing apparatus 100 illustrated in FIG. 2 is that the information processing apparatus 100 illustrated in FIG. 7 includes a movement amount calculation unit 701.

[0053] The movement amount calculation unit 701 calculates a movement amount 702 between a first region of interest set for an image of a first frame and a second region of interest set for an image of a frame different from the first frame among a plurality of second frames. The movement amount calculation unit 701 outputs a set of the movement amount 702 and the identification information 703 for each frame different from the first frame among the plurality of second frames to the pixel value synthesis unit 205. The identification information 703 is information for identifying the frame in which the second region of interest used for calculating the movement amount 702 is set. The movement amount 702 is calculated based on at least any one selected from the group consisting of a difference in position between the first region of interest and the second region of interest, a difference in area between the first region of interest and the second region of interest, and a rotation angle between the first region of interest and the second region of interest.

[0054] The pixel value synthesis unit 205 according to the present embodiment weights each of the plurality of first representative values 214 according to the movement amount 702. Note that the images of the plurality of second frames may indicate a plurality of images captured within a time determined according to the movement amount 702.

[0055] FIG. 8 is a flowchart showing an example of the operation of the information processing apparatus 100 according to the present embodiment. Since the processes in steps S801 to S804 are the same as the processes in steps S301 to S304 illustrated in FIG. 3, detailed description thereof is omitted.

[0056] When a plurality of second frames cannot be selected in step S804, the control unit 202 shifts the process to step S805. Since the process in step S805 is the same as the process in step S305 illustrated in FIG. 3, detailed description thereof is omitted. Then, the control unit 202 shifts the process to step S806. Since the processes in steps S806 to S807 are the same as the processes in steps S308 to S309 illustrated in FIG. 3, detailed description thereof is omitted. On the other hand, when a plurality of second frames can be selected in step S804, the control unit 202 shifts the process to step S901 illustrated in FIG. 9.

[0057] Next, with reference to FIG. 9, the operation of the information processing apparatus 100 according to the present embodiment will be continued.

[0058] In step S901, the movement amount calculation unit 701 calculates a movement amount 702 between a first region of interest set for the image of the first frame selected in step S803 illustrated in FIG. 8 and a second region of interest set for the image of a frame different from the first frame among the plurality of second frames selected in step S804 illustrated in FIG. 8. That is, the movement amount calculation unit 701 calculates the movement amount 702 between the first region of interest and the second region of interest for each frame different from the first frame among the plurality of second frames. Then, the movement amount calculation unit 701 outputs a set of the movement amount 702 and the identification information 703 for each frame different from the first frame among the plurality of second frames to the pixel value synthesis unit 205. The identification information 703 is information for identifying the frame in which the movement amount 702 is calculated.

[0059] The movement amount 702 is calculated based on at least any one selected from the group consisting of the difference in position between the first region of interest and the second region of interest, the difference in area between the first region of interest and the second region of interest, and the rotation angle between the first region of interest and the second region of interest.

[0060] For example, the difference in position between the first region of interest and the second region of interest is the distance between the coordinates of the center of the first region of interest and the coordinates of the center of the second region of interest. For example, when the first region of interest is a polygon, the center of the first region of interest is the centroid of the first region of interest. Similarly, when the second region of interest is a polygon, the center of the second region of interest is the centroid of the second region of interest.

[0061] Further, for example, the difference in area between the first region of interest and the second region of interest is the difference value between the area of the first region of interest and the area of the second region of interest. Alternatively, the difference in area between the first region of interest and the second region of interest may indicate the ratio of the area of the second region of interest to the area of the first region of interest.

[0062] Also, for example, the rotation angle between the first region of interest and the second region of interest is the rotation angle calculated from the optical flow of corresponding pixels in the pixels included in the first region of interest and the pixels included in the second region of interest. Note that the movement amount calculation unit 701 only needs to be able to calculate the rotation angle between the first region of interest and the second region of interest, and the details of the calculation method are not limited.

[0063] In step S902, the pixel value calculation unit 204 calculates a plurality of first representative values 214 of the pixel values of the pixels at the positions of the plurality of regions of interest set in the images of the plurality of second frames in the image of the first frame. Since the process of step S902 is the same as the process of step S306 illustrated in FIG. 3, a detailed description thereof is omitted.

[0064] In step S903, the pixel value synthesis unit 205 weights each of the plurality of first representative values 214 according to the movement amount 702. For example, it is assumed that the living body 102 has moved between the time when the image of the first frame in which the first region of interest is set is captured and the time when the image of the frame in which the second region of interest is set is captured. In that case, it is assumed that the movement amount 702 between the position of the first region of interest and the position of the second region of interest is relatively large in the image of the first frame. Therefore, for example, the pixel value synthesis unit 205 weights the first representative value 214 relatively smaller for the position of the second region of interest where the movement amount 702 is relatively large.

[0065] In step S904, the pixel value synthesis unit 205 synthesizes the plurality of first representative values 214 weighted in step S903 to calculate a second representative value 216. Then, the control unit 202 proceeds to step S806 illustrated in FIG. 8.

[0066] For example, assume that the pixel value synthesizing unit 205 assigns a relatively smaller weight to the first representative value 214 as the position of the second region of interest where the movement amount 702 is relatively large. As a result, the pixel value synthesizing unit 205 can calculate the second representative value 216 without emphasizing the first representative value 214 calculated at a position relatively far from the position of the first region of interest among the positions of the plurality of regions of interest set in the plurality of second frames.

[0067] When the living body 102 moves, the variation in the position of the region of interest set in the second frame may increase, and the noise included in the pulse wave signal may increase. However, the information processing apparatus 100 according to the present embodiment synthesizes a plurality of first representative values 214 weighted according to the movement amount of the region of interest to calculate the second representative value 216. Therefore, the information processing apparatus 100 according to the present embodiment has the same effect as the information processing apparatus 100 according to the first embodiment, and can suppress the use of the pixel values of pixels that are irrelevant for calculating the pulse wave signal due to the movement of the living body 102.

[0068] Each process executed in the above embodiment is not limited to the processing modes exemplified in each embodiment. The above-described functional blocks may be realized by either a logic circuit (hardware) formed in an integrated circuit or the like, or software using a CPU. The above embodiment may be executed by a plurality of computers. For example, the processes executed by the respective functional blocks of the control unit 202 of the information processing apparatus 100 may be partially executed by other computers, or all the processes may be executed in a distributed manner by a plurality of computers.

[0069] The present disclosure is not limited to the above embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above embodiments, a configuration that exhibits the same operational effects, or a configuration that can achieve the same purpose. The present disclosure also includes embodiments obtained by appropriately combining the technical means disclosed in different embodiments. Furthermore, by combining the technical means disclosed in each embodiment, new technical features can be formed.

Description of Reference Numerals

[0070] 100 Information processing apparatus, 101 Imaging unit, 102 Living body, 201 Memory unit, 202 Control unit, 203 Region of interest setting unit, 204 Pixel value calculation unit, 205 Pixel value synthesis unit, 206 Pulse wave calculation unit, 211 Moving image, 212 Region of interest information, 213 Identification information, 214 First representative value, 215 Identification information, 216 Second representative value, 217 Identification information, 400 Region of interest, 401 Region of interest, 402 Region of interest, 403 Region of interest, 404 Region of interest, 501 Time series signal, 502 Time series signal, 503 Period, 601 Pulse wave signal, 602 Pulse wave signal, 701 Movement amount calculation unit, 702 Movement amount, 703 Identification information

Claims

1. An interest area setting unit that sets the position of an interest area for the image of each frame constituting a moving image obtained by imaging a living body, A pixel value calculation unit that calculates a plurality of first representative values of pixel values of pixels at the positions of a plurality of interest areas set for images of a plurality of second frames including the image of the first frame constituting the moving image in the image of the first frame, A pixel value synthesis unit that synthesizes the plurality of first representative values to calculate a second representative value for the first frame, A pulse wave calculation unit that calculates a pulse wave signal from the temporal change of the second representative value, An information processing apparatus comprising:

2. An imaging unit that images the living body and acquires the moving image further comprising The information processing apparatus according to claim 1.

3. The second representative value is When the plurality of second frames are selected for the first frame, it is calculated by the pixel value synthesis unit, and when the plurality of second frames are not selected for the first frame, it is the representative value of the pixel values of the pixels at the positions of the interest areas set for the image of the first frame The information processing apparatus according to claim 1 or 2.

4. The images of the plurality of second frames indicate a plurality of images captured within a predetermined time The information processing apparatus according to claim 1 or 2.

5. The images of the plurality of second frames indicate a plurality of images captured continuously The information processing apparatus according to claim 1 or 2.

6. The images of the plurality of second frames indicate the image of the first frame and the image of at least one frame captured before the first frame The information processing apparatus according to claim 1 or 2.

7. The images of the plurality of second frames indicate the image of the first frame and the image of at least one frame captured after the first frame The information processing apparatus according to claim 1 or 2.

8. The pixel value synthesis unit weights each of the plurality of first representative values and synthesizes the weighted plurality of first representative values to calculate the second representative value The information processing apparatus according to claim 1 or 2.

9. A movement amount calculation unit that calculates a movement amount between a first interest area set for the image of the first frame and a second interest area set for the image of a frame different from the first frame among the plurality of second frames further comprising The pixel value synthesis unit weights each of the plurality of first representative values according to the movement amount The information processing apparatus according to claim 8.

10. The amount of movement is calculated based on at least any one selected from the group consisting of a difference in position between the first region of interest and the second region of interest, a difference in area between the first region of interest and the second region of interest, and a rotation angle between the first region of interest and the second region of interest. The information processing apparatus according to claim 9.

11. The images of the plurality of second frames indicate a plurality of images captured within a time determined according to the amount of movement. The information processing apparatus according to claim 9.

12. A step of setting a position of a region of interest for each image of a frame constituting a moving image of a living body; A step of calculating a plurality of first representative values of pixel values of pixels at positions of a plurality of regions of interest set for a plurality of images of second frames including the image of the first frame constituting the moving image, in the image of the first frame; A step of synthesizing the plurality of first representative values to calculate a second representative value for the first frame; A step of calculating a pulse wave signal from a temporal change of the second representative value; A pulse wave calculation method including the above steps.

13. A program causing a computer to execute a function of setting a position of a region of interest for each image of a frame constituting a moving image of a living body; execute a function of calculating a plurality of first representative values of pixel values of pixels at positions of a plurality of regions of interest set for a plurality of images of second frames including the image of the first frame constituting the moving image, in the image of the first frame; execute a function of synthesizing the plurality of first representative values to calculate a second representative value for the first frame; execute a function of calculating a pulse wave signal from a temporal change of the second representative value. ​

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