Biosignal acquisition device, biosignal acquisition method, and biosignal acquisition program

Abstract

To provide a biological signal acquisition device, a biological signal acquisition method, and a biological signal acquisition program capable of acquiring a biological signal in which the state of a living body is reflected with a high degree of precision.SOLUTION: A biological signal acquisition device includes: an imaging unit for performing imaging according to an imaging condition, and outputting pixel values of a plurality of pixels of each channel included in two or more channels corresponding to two or more mutually different wavelength ranges respectively; a representative value calculation unit for calculating a representative value of each channel from pixel values of a plurality of in-region pixels in a region in which the living body is imaged, included in the pixel values of the plurality of pixels; a control unit for setting the imaging condition so that the representative value of each channel is a setting value or more of each channel; and a biological signal calculation unit for calculating a biological signal from the representative value of the two or more channels.SELECTED DRAWING: Figure 1

Description

Technical Field

[0004] , , , ,

[0005] , , , ,

[0001] The present disclosure relates to a biological signal acquisition device, a biological signal acquisition method, and a biological signal acquisition program.

Background Art

[0002] Patent Document 1 discloses an imaging control device. The imaging control device controls the exposure time, gain, white balance, etc. such that the average value μr of the distribution of R signal values, the average value μg of the distribution of G signal values, and the average value μb of the distribution of B signal values of the pixels in the biological image satisfy the conditions μr < Rmax, |μg - St| < ε, and μb > Bmin. Thereby, the change in the G signal value with respect to the change in the light intensity of the G light absorbed by hemoglobin can be increased. Thereby, the signal-to-noise ratio of the biological signal can be increased (paragraphs 0010, 0034, 0082, and 0085).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the imaging control device disclosed in Patent Document 1, the G signal value can be kept within a range suitable for detecting a biological signal. However, the R signal value and the B signal value cannot be kept within a range suitable for detecting a biological signal and noise. Therefore, noise cannot be removed using the R signal value and the B signal value when detecting a biological signal from the G signal value.

[0005] The present disclosure has been made in view of this problem. An object of the present disclosure is to provide, for example, a biological signal acquisition device, a biological signal acquisition method, and a biological signal acquisition program capable of acquiring a biological signal that accurately reflects the state of a living body. [Means for solving the problem]

[0006] A biosignal acquisition device according to a first aspect of the present disclosure includes an imaging unit that performs imaging in accordance with imaging conditions and outputs pixel values ​​of a plurality of pixels in each of two or more channels that correspond to two or more mutually different wavelength bands, a representative value calculation unit that calculates a representative value of each channel from pixel values ​​of a plurality of intra-region pixels in an area in which a living body is captured, the pixel values ​​of the plurality of pixels being included in the pixel values ​​of the plurality of pixels, a control unit that sets the imaging conditions so that the representative value of each channel is equal to or greater than a set value for each channel, and a biosignal calculation unit that calculates a biosignal from the representative values ​​of the two or more channels.

[0007] A biological signal acquisition method according to a second aspect of the present disclosure includes performing imaging in accordance with imaging conditions and outputting pixel values ​​of a plurality of pixels in each of two or more channels corresponding to two or more mutually different wavelength bands, calculating a representative value of each channel from pixel values ​​of a plurality of pixels in an area in which a biological body is captured, the pixel values ​​of the plurality of pixels being included in the pixel values ​​of the plurality of pixels, setting the imaging conditions so that the representative value of each channel is equal to or greater than a set value for each channel, and calculating a biological signal from the representative values ​​of the two or more channels.

[0008] A biosignal acquisition program of a third aspect of the present disclosure causes a computer to perform the following operations: cause an imaging unit to perform imaging in accordance with imaging conditions and output pixel values ​​of multiple pixels in each of two or more channels corresponding to two or more mutually different wavelength bands; calculate a representative value of each channel from pixel values ​​of multiple in-region pixels in an area in which a living body is captured, which are included in the pixel values ​​of the multiple pixels; set the imaging conditions so that the representative value of each channel is equal to or greater than a set value for each channel; and calculate a biosignal from the representative values ​​of the two or more channels. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram of a pulse wave signal acquiring device according to a first embodiment. [Figure 2] 3A to 3C are diagrams showing the content of processing performed by an imaging section provided in the pulse wave signal acquiring device of the first embodiment. [Figure 3] 3 is a diagram showing the content of processing performed by a control unit provided in the pulse wave signal acquiring device of the first embodiment. FIG. [Figure 4] 3 is a diagram showing the content of processing performed by a control unit provided in the pulse wave signal acquiring device of the first embodiment. FIG. [Figure 5] 3 is a diagram showing the content of processing performed by a representative value calculation unit provided in the pulse wave signal acquisition device of the first embodiment. FIG. [Figure 6] 3 is a diagram showing the relationship between values ​​used in processing performed by a control unit provided in the pulse wave signal acquiring device of the first embodiment. FIG. [Figure 7] 3 is a diagram showing the content of processing performed by a representative value calculation unit, a control unit, and a pulse wave signal calculation unit provided in the pulse wave signal acquisition device of the first embodiment. FIG. [Figure 8] 10 is a diagram showing the processing performed by a representative value calculation section, a control section, and a pulse wave signal calculation section provided in a pulse wave signal acquisition device according to a first modification of the first embodiment. FIG. [Figure 9] 3 is a diagram showing the content of processing that is preferably performed by a representative value calculation section and a control section provided in the pulse wave signal calculation device of the first embodiment. FIG. [Figure 10] 2 is a block diagram of an imaging unit provided in the pulse wave signal acquiring device of the first embodiment. FIG. [Figure 11] 10 is a diagram showing the content of processing performed by a representative value calculation section provided in a pulse wave signal acquisition device according to a second modification of the first embodiment and a first modification of the second embodiment. FIG. [Figure 12] 10A and 10B are diagrams showing the content of processing performed by a display control unit provided in a pulse wave signal acquiring device according to a third modification of the first embodiment and a second modification of the second embodiment. [Figure 13]2 is a block diagram of a representative value calculation unit, a pulse wave signal calculation unit, a control unit, and a computer that functions as a display control unit, which are provided in the pulse wave signal acquisition device of the first embodiment. FIG. [Figure 14] 3 is a flowchart showing the flow of processing performed by the pulse wave signal acquiring device of the first embodiment. [Figure 15] FIG. 10 is a block diagram of an imaging unit provided in a pulse wave signal acquiring device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0011] 1. First embodiment 1.1 Overview of the pulse wave signal acquisition device FIG. 1 is a block diagram of a pulse wave signal acquiring device according to a first embodiment.

[0012] The pulse wave signal acquiring device 1 of the first embodiment shown in FIG. 1 images a human body HB and acquires a pulse wave signal 22 of the imaged human body HB. The acquired pulse wave signal 22 is a signal indicating a pulse wave. The human body HB is an example of a living body. The pulse wave signal acquiring device 1 may also image a living body other than the human body HB and acquire a pulse wave signal 22 of the imaged living body. The pulse wave signal 22 is an example of a biological signal. The configuration described below may be employed in a biological signal acquiring device that acquires a biological signal other than the pulse wave signal 22. The acquired biological signal reflects the state of the living body.

[0013] As shown in FIG. 1, pulse wave signal acquiring device 1 includes imaging section 11, representative value calculating section 12, pulse wave signal calculating section 13, control section 14, and display control section 15.

[0014] The imaging unit 11 captures images and outputs a moving image in accordance with the imaging conditions 21. The output moving image includes a plurality of frame images.

[0015] The imaging unit 11 is an RGB camera. Therefore, each of the frame images includes pixel values ​​PV(R1),...,PV(Rn) of multiple pixels R1,...,Rn in the R (red) channel, pixel values ​​PV(G1),...,PV(Gn) of multiple pixels G1,...,Gn in the G (green) channel, and pixel values ​​PV(B1),...,PV(Bn) of multiple pixels B1,...,Bn in the B (blue) channel.

[0016] The R channel, G channel, and B channel correspond to the R wavelength band, the G wavelength band, and the B wavelength band, respectively.

[0017] Three wavelength bands consisting of an R wavelength band, a G wavelength band, and a B wavelength band are an example of two or more wavelength bands that are different from each other. Three channels consisting of an R channel, a G channel, and a B channel are an example of two or more channels that are different from each other. A frame image may include pixel values ​​of multiple pixels in each channel included in two or more channels that respectively correspond to two or more wavelength bands other than the three wavelength bands.

[0018] The representative value calculation unit 12 calculates an R channel representative value RV(R) from the pixel values ​​of multiple intra-region pixels in the region of interest included in the output pixel values ​​PV(R1),...,PV(Rn). The representative value calculation unit 12 calculates a G channel representative value RV(G) from the pixel values ​​of multiple intra-region pixels in the region of interest included in the output pixel values ​​PV(G1),...,PV(Gn). The representative value calculation unit 12 calculates a B channel representative value RV(B) from the pixel values ​​of multiple intra-region pixels in the region of interest included in the output pixel values ​​PV(B1),...,PV(Bn). The calculated representative values ​​RV(R), RV(G), and RV(B) may be averages, maximum values, minimum values, modes, medians, etc.

[0019] The control unit 14 sets the imaging conditions 21 so that the representative value RV(R) is equal to or greater than the set value SV(R) of the R channel, the representative value RV(G) is equal to or greater than the set value SV(G) of the G channel, and the representative value RV(B) is equal to or greater than the set value SV(B) of the B channel.

[0020] Pulse wave signal calculation unit 13 calculates pulse wave signal 22 from representative values ​​RV(R), RV(G), and RV(B) using techniques such as independent component analysis and pigment component separation. The calculated pulse wave signal 22 reflects the pulse wave of the human body HB.

[0021] The display control unit 15 displays frame images corresponding to the output pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) on the display.

[0022] 1.2 Quantization of received light amount FIG. 2 is a diagram showing the content of the processing performed by the imaging unit provided in the pulse wave signal acquiring device of the first embodiment.

[0023] 2, the imaging unit 11 converts the amounts of light received by pixels R1,...,Rn, A(R1),...,A(Rn), into pixel values ​​PV(R1),...,PV(Rn), respectively. The imaging unit 11 converts the amounts of light received by pixels G1,...,Gn, A(G1),...,A(Gn), into pixel values ​​PV(G1),...,PV(Gn), respectively. The imaging unit 11 converts the amounts of light received by pixels B1,...,Bn, A(B1),...,A(Bn), into pixel values ​​PV(B1),...,PV(Bn), respectively.

[0024] The imaging unit 11 increases the pixel values ​​PV(R1),...,PV(Rn) as the received light amounts A(R1),...,A(Rn) increase. The imaging unit 11 increases the pixel values ​​PV(G1),...,PV(Gn) as the received light amounts A(G1),...,A(Gn) increase. The imaging unit 11 increases the pixel values ​​PV(B1),...,PV(Bn) as the received light amounts A(B1),...,A(Bn) increase.

[0025] The amounts of received light A(R1),...,A(Rn),A(G1),...,A(Gn),A(B1),...,A(Bn) are continuous quantities. The pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) are discrete values. Therefore, the imaging unit 11 quantizes the amounts of received light A(R1),...,A(Rn) to obtain the pixel values ​​PV(R1),...,PV(Rn). The imaging unit 11 quantizes the amounts of received light A(G1),...,A(Gn) to obtain the pixel values ​​PV(G1),...,PV(Gn). The imaging unit 11 quantizes the amounts of received light A(B1),...,A(Bn) to obtain the pixel values ​​PV(B1),...,PV(Bn).

[0026] 1.3 Parameters used to control the imaging unit As shown in FIG. 2, the parameters used to control the image capturing unit 11 include a gain 31, an ISO sensitivity 32, and a white balance 33.

[0027] The gain 31 and ISO sensitivity 32 indicate the degree of amplification applied to pixel signals indicating the amounts of received light A(R1),...,A(Rn),A(G1),...,A(Gn),A(B1),...,A(Bn). Therefore, when the amounts of received light A(R1),...,A(Rn),A(G1),...,A(Gn),A(B1),...,A(Bn) are constant, the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(G1),...,PV(Gn) increase as the gain 31 or ISO sensitivity 32 increases.

[0028] White balance 33 indicates the ratio of pixel values ​​of three channels consisting of pixel values ​​indicating the amount of received light A(R1),...,A(Rn), pixel values ​​indicating the amount of received light A(G1),...,A(Gn), and pixel values ​​indicating the amount of received light A(B1),...,A(Bn).

[0029] 1.4 Imaging conditions As shown in FIG. 1, the imaging conditions 21 include a gain g, an R channel gain gR, a G channel gain gG, and a B channel gain gB.

[0030] The imaging unit 11 outputs pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) according to the gain g. When the gain g increases, the imaging unit 11 increases all of the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn).

[0031] The imaging unit 11 outputs pixel values ​​PV(R1),...,PV(Rn) according to the gain gR. When the gain gR increases, the imaging unit 11 increases the pixel values ​​PV(R1),...,PV(Rn) without changing the pixel values ​​PV(G1),...,PV(Gn),PV(B1),...,PV(Bn).

[0032] The imaging unit 11 outputs pixel values ​​PV(G1),...,PV(Gn) according to the gain gG. When the gain gG increases, the imaging unit 11 increases the pixel values ​​PV(G1),...,PV(Gn) without changing the pixel values ​​PV(R1),...,PV(Rn),PV(B1),...,PV(Bn).

[0033] The imaging unit 11 outputs pixel values ​​PV(B1),...,PV(Bn) according to the gain gB. When the gain gB increases, the imaging unit 11 increases the pixel values ​​PV(B1),...,PV(Bn) without changing the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn).

[0034] When adjusting the gain 31 or the ISO sensitivity 32, the control unit 14 adjusts the gain g to adjust the pixel values ​​PV(R1), . . ., PV(Rn), PV(G1), . . ., PV(Gn), PV(B1), . . ., PV(Bn) as a whole. If the pixel values ​​PV(Ri), PV(Gi), and PV(Bi) are 100 when the gain g is 1, the pixel values ​​PV(Ri), PV(Gi), and PV(Bi) are 150 when the gain g is 1.5.

[0035] When correcting the white balance 33, the control unit 14 adjusts the gains gR, gG, and gB individually to adjust the pixel values ​​PV(R1),...,PV(Rn), the pixel values ​​PV(G1),...,PV(Gn), and the pixel values ​​PV(B1),...,PV(Bn). The control unit 14 can adjust each gain included in the gains gR, gG, and gB independently from the remaining gain included in the gains gR, gG, and gB. This allows the control unit 14 to adjust the ratios of the pixel values ​​of the three channels consisting of the pixel values ​​PV(R1),...,PV(Rn), the pixel values ​​PV(G1),...,PV(Gn), and the pixel values ​​PV(B1),...,PV(Bn). If the pixel values ​​PV(Ri), PV(Gi), and PV(Bi) are 100 when the white balance 33 is not corrected and the gains gR, gG, and gB are 1, then when the white balance is corrected and the gains gR, gG, and gB are 0.9, 0.8, and 0.7, respectively, the pixel values ​​PV(Ri), PV(Gi), and PV(Bi) are 90, 80, and 70, respectively.

[0036] 1.5 Gain Settings 3 and 4 are diagrams showing the content of the processing performed by the control unit provided in the pulse wave signal acquiring device of the first embodiment.

[0037] When correcting the white balance 33, the control unit 14 changes the gains gR, gG, and gB from the reference gains of the R channel, G channel, and B channel, respectively. For example, as shown in Fig. 3, the control unit 14 changes the gains gR, gG, and gB from the reference gain of 1 to 0.9, 0.8, and 0.7 for the R channel, G channel, and B channel, respectively.

[0038] Alternatively, when correcting the white balance 33, the control unit 14 sets the ratio of the gain of the second channel to the gain of the first channel. The control unit 14 sets the gain of the first channel as the reference gain of the first channel and the gain of the second channel as the product of the reference gain of the first channel and the set ratio. For example, as shown in FIG. 4, the control unit 14 sets the G channel as the first channel and the R and B channels as the second channels. The control unit 14 sets the ratio gR / G of the gain gR to the gain gG to 1.2 and sets the ratio gB / G of the gain gB to the gain gG to 0.8. The control unit 14 sets the gain gG to the reference gain of the G channel to 1, the gain gR to the product of the reference gain of the G channel 1 and the ratio gR / G = 1.2, and the gain gB to the product of the reference gain of the G channel 1 and the ratio gB / G = 0.8.

[0039] 1.6 Calculation of representative values FIG. 5 is a diagram showing the content of the processing performed by the representative value calculation unit provided in the pulse wave signal acquisition device of the first embodiment.

[0040] 5, the representative value calculation unit 12 extracts pixel values ​​PV(Rp),...,PV(Rq) of pixels Rp,...,Rq in the set region of interest 41 from pixel values ​​PV(R1),...,PV(Rn). The representative value calculation unit 12 extracts pixel values ​​PV(Gp),...,PV(Gq) of pixels Gp,...,Gq in the set region of interest 41 from pixel values ​​PV(G1),...,PV(Gn). The representative value calculation unit 12 extracts pixel values ​​PV(Bp),...,PV(Bq) of pixels Bp,...,Bq in the set region of interest 41 from pixel values ​​PV(B1),...,PV(Bn).

[0041] The region of interest 41 is an area included in the frame image in which the human body HB is captured. The change in color of the region of interest 41 over time reflects the pulse wave of the human body HB. Therefore, a pulse wave signal 22 reflecting the pulse wave of the human body HB can be calculated from the pixel values ​​PV(Rp), . . . PV(Rq), PV(Gp), . . . PV(Gq), PV(Bp), . . . PV(Bq).

[0042] The region of interest 41 is set within the image of the exposed skin of the human body HB. For example, the region of interest 41 is set within the images of the face, cheeks, forehead, palms, wrists, and soles of the feet.

[0043] The representative value calculation unit 12 calculates a representative value RV(R) of the extracted pixel values ​​PV(Rp),...,PV(Rq). The representative value calculation unit 12 calculates a representative value RV(G) of the extracted pixel values ​​PV(Gp),...,PV(Gq). The representative value calculation unit 12 calculates a representative value RV(B) of the extracted pixel values ​​PV(Bp),...,PV(Bq).

[0044] 1.7 Advantages of setting imaging conditions so that the representative value is equal to or greater than the set value Light incident on the skin of human body HB is mainly absorbed by melanin. For this reason, the amount of light in each wavelength band contained in the light diffusely reflected by the skin of human body HB decreases as the absorption intensity of light in each wavelength band by melanin increases. In melanin, the absorption intensity of R light, the absorption intensity of G light, and the absorption intensity of B light increase in the listed order, so when white light is incident on the skin of human body HB, the amount of R light, the amount of G light, and the amount of B light in the light diffusely reflected by the skin of human body HB decrease in the listed order.

[0045] Light incident on the skin of the human body HB is also absorbed by hemoglobin. For this reason, the amount of light diffusely reflected by the skin of the human body HB decreases as the amount of hemoglobin increases. For this reason, the amount of light in each wavelength band contained in the light diffusely reflected by the skin of the human body HB changes over time in synchronization with the change in the amount of hemoglobin due to blood vessel pulsation. Of the amounts of R light, G light, and B light, the amount of G light changes the most over time. However, the change over time in the amount of G light is also very small. Therefore, when the imaging unit 11 is a general-purpose camera and the bit length of the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) is short, for example, when the bit length is 8 bits and the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) can only take on 256 values ​​from 0 to 255, it is necessary to increase the number of gradations assigned to the time changes in the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) in order to detect small changes over time in the amount of light in each wavelength band that are caused by changes over time in the amount of hemoglobin.

[0046] In order to increase the number of gradations that can be assigned to the time changes of the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn), it is effective to increase the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) within a range in which the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) do not saturate. This can be understood from the fact that, for example, if the range of the minute change in the amount of G light over time caused by the minute change in the amount of hemoglobin over time is approximately 1% of the steady amount of G light, when the pixel value PV(Gi) is 100, the number of gradations assigned to the time change of the pixel value PV(Gi) will be approximately 1, and when the pixel value PV(Gi) is 200, the number of gradations will be approximately 2.

[0047] Taking this into consideration, control unit 14 sets imaging conditions 21 so that representative value RV(R) is equal to or greater than set value SV(R), representative value RV(G) is equal to or greater than set value SV(G), and representative value RV(B) is equal to or greater than set value SV(B). This increases the number of gradations that can be assigned to the temporal changes in representative values ​​RV(R), RV(G), and RV(B). This allows pulse wave signal 22 to accurately reflect the temporal changes in the amount of light in each wavelength band contained in the light diffusely reflected by the skin of human body HB.

[0048] 1.8 Setting value range FIG. 6 is a diagram showing the relationship between values ​​used in the processing performed by the control unit provided in the pulse wave signal acquiring device of the first embodiment.

[0049] 6, pixel values ​​PV(R1),...,PV(Rn) can take on values ​​within a range 51R from the lower limit LL(R) of the R channel to the upper limit UL(R) of the R channel. Pixel values ​​PV(G1),...,PV(Gn) can take on values ​​within a range 51G from the lower limit LL(G) of the G channel to the upper limit UL(G) of the G channel. Pixel values ​​PV(B1),...,PV(Bn) can take on values ​​within a range 51B from the lower limit LL(B) of the B channel to the upper limit UL(B) of the B channel.

[0050] The set value SV(R) is preferably equal to or greater than the center value CV(R) of the range 51R and is made as large as possible. The set value SV(G) is preferably equal to or greater than the center value CV(G) of the range 51G and is made as large as possible. The set value SV(B) is preferably equal to or greater than the center value CV(B) of the range 51B and is made as large as possible. This makes it possible to increase the representative values ​​RV(R), RV(G), and RV(B), and to increase the number of gradations that can be assigned to the time changes of the representative values ​​RV(R), RV(G), and RV(B).

[0051] The set value SV(R), the set value SV(G), and the set value SV(B) may be the same value or may be different values ​​from each other.

[0052] The control unit 14 may set the imaging conditions 21 so that the representative value RV(R) is equal to or greater than the set value SV(R) and equal to or less than the upper limit set value USV(R) of the R channel, the representative value RV(G) is equal to or greater than the set value SV(G) and equal to or less than the upper limit set value USV(G) of the G channel, and the representative value RV(B) is equal to or greater than the set value SV(B) and equal to or less than the upper limit set value USV(B) of the B channel. In other words, the control unit 14 may set the imaging conditions 21 so that the representative value RV(R) takes a value within the range from the set value SV(R) to the upper limit set value USV(R), the representative value RV(G) takes a value within the range from the set value SV(G) to the upper limit set value USV(G), and the representative value RV(B) takes a value within the range from the set value SV(B) to the upper limit set value USV(B).

[0053] The upper limit set values ​​USV(R), USV(G), and USV(B) may be the same value or may be different values ​​from each other.

[0054] The upper limit setting value USV(R) is smaller than the upper limit value UL(R) of range 51R. The upper limit setting value USV(G) is smaller than the upper limit value UL(G) of range 51G. The upper limit setting value USV(B) is smaller than the upper limit value UL(B) of range 51B. This makes it possible to prevent the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) from becoming saturated, even if the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) increase due to body movement of the human body HB, an increase in the intensity of the illumination light illuminating the human body HB, etc.

[0055] When the bit length of the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) is 8 bits, for example, the setting values ​​SV(R), SV(G) and SV(B) are set to 200, and the upper limit setting values ​​USV(R), USV(G) and USV(B) are set to 230. As a result, the representative values ​​RV(R), RV(G) and RV(B) take values ​​within the range from 200 to 230.

[0056] The size of the range from the set value SV(R) to the upper set value USV(R) is determined to be the same as the size of the range of change in pixel values ​​PV(R1),...,PV(Rn) due to body movement, etc. of the human body HB. The size of the range from the set value SV(G) to the upper set value USV(G) is determined to be the same as the size of the range of change in pixel values ​​PV(G1),...,PV(Gn) due to body movement, etc. of the human body HB. The size of the range from the set value SV(B) to the upper set value USV(B) is determined to be the same as the size of the range of change in pixel values ​​PV(B1),...,PV(Bn) due to body movement, etc. of the human body HB. This makes it possible to prevent the ranges from the set value SV(G) to the upper set value USV(G), the range from the set value SV(B) to the upper set value USV(B), and the range from the set value SV(G) to the upper set value USV(G) from becoming too small, thereby preventing the time required to set the imaging condition 21 from becoming too long.

[0057] 1.9 Calculation of pulse wave signal from representative values FIG. 7 is a diagram showing the processing performed by the representative value calculation unit, the control unit, and the pulse wave signal calculation unit provided in the pulse wave signal acquisition device of the first embodiment.

[0058] In the first embodiment, as shown in Fig. 7, representative value calculation unit 12 calculates representative values ​​RV(R), RV(G), and RV(B). Control unit 14 compares representative values ​​RV(R), RV(G), and RV(B) with set values ​​SV(R), SV(G), and SV(B), respectively, and sets imaging conditions 21 so that representative value RV(R) is equal to or greater than set value SV(R), representative value RV(G) is equal to or greater than set value SV(G), and representative value RV(B) is equal to or greater than set value SV(B). Pulse wave signal calculation unit 13 calculates pulse wave signal 22 from the temporal changes in representative values ​​RV(R), RV(G), and RV(B) calculated after imaging conditions 21 are set.

[0059] The time variation of each of the representative values ​​RV(R), RV(G), and RV(B) includes a pulse wave component resulting from the time variation of the amount of hemoglobin due to the pulsation of the human body HB, a first noise component resulting from the time variation of the amount of melamine, and a second noise component resulting from the body movement of the human body HB. The ratios of the pulse wave component, the first noise component, and the second noise component included in the time variation of the representative value RV(R), the ratios of the pulse wave component, the first noise component, and the second noise component included in the time variation of the representative value RV(G), and the ratios of the pulse wave component, the first noise component, and the second noise component included in the time variation of the representative value RV(B) are different from one another.

[0060] Pulse wave signal calculation unit 13 calculates pulse wave signal 22 from the time changes in the representative values ​​of the three channels consisting of representative values ​​RV(R), RV(G), and RV(B), thereby separating the pulse wave component, first noise component, and second noise component contained in the time changes of each of representative values ​​RV(R), RV(G), and RV(B). Thus, pulse wave signal calculation unit 13 uses the time changes of representative value RV(R) and representative value RV(B) to remove the first noise component and second noise component from the time change of representative value RV(G), extract the pulse wave component from the time change of representative value RV(G), and calculates pulse wave signal 22 from the extracted pulse wave component.

[0061] In pulse wave signal acquisition device 1, the number of gradations assigned to the time changes of representative values ​​RV(R), RV(G), and RV(B) is increased, so that the pulse wave can be accurately reflected in representative values ​​RV(R), RV(G), and RV(B). As a result, the pulse wave can be accurately reflected in pulse wave signal 22 calculated from representative values ​​RV(R), RV(G), and RV(B).

[0062] FIG. 8 is a diagram showing the processing performed by the representative value calculation section, the control section, and the pulse wave signal calculation section provided in the pulse wave signal acquisition device of the first modified example of the first embodiment.

[0063] 8, in the first modification of the first embodiment, the representative value calculation unit 12 can calculate a first representative value RV1(R) and a second representative value RV2(R) as the representative value RV(R). Also, the representative value calculation unit 12 can calculate a first representative value RV1(G) and a second representative value RV2(G) as the representative value RV(G). Also, the representative value calculation unit 12 can calculate a first representative value RV1(B) and a second representative value RV2(B) as the representative value RV(B). Control unit 14 compares first representative values ​​RV1(R), RV1(G), and RV1(B) with set values ​​SV(R), SV(G), and SV(B), respectively, and sets imaging conditions 21 so that first representative value RV1(R) is equal to or greater than set value SV(R), first representative value RV1(G) is equal to or greater than set value SV(G), and first representative value RV1(B) is equal to or greater than set value SV(B). Pulse wave signal calculation unit 13 calculates pulse wave signal 22 from the temporal changes in second representative values ​​RV2(R), RV2(G), and RV2(B), which are calculated after imaging conditions 21 are set.

[0064] The first representative value RV1(R) and the second representative value RV2(R) are two types of representative values ​​calculated from the same pixel values ​​PV(R1),...,PV(Rn). The first representative value RV1(G) and the second representative value RV2(G) are two types of representative values ​​calculated from the same pixel values ​​PV(G1),...,PV(Gn). The first representative value RV1(B) and the second representative value RV2(B) are two types of representative values ​​calculated from the same pixel values ​​PV(B1),...,PV(Bn). The first representative values ​​RV1(R), RV1(G), and RV1(B) are, for example, maximum values. The second representative values ​​RV2(R), RV2(G), and RV2(B) are, for example, average values.

[0065] 1.10 White balance correction to bring the representative value closer FIG. 9 is a diagram showing the content of processing that is preferably performed by the representative value calculation section and the control section provided in the pulse wave signal calculation device of the first embodiment.

[0066] In light diffusely reflected by the skin of the human body HB, the amount of R light is greater than the amounts of G light and B light. When the skin is illuminated with warm-colored illumination light having a strong reddish tint, the amount of R light is even greater than when the skin is illuminated with white illumination light. Therefore, if the imaging conditions 21 are set simply so that the pixel values ​​PV(R1),...,PV(Rn) do not saturate, the pixel values ​​PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) may become too small. This may result in a low signal-to-noise ratio (S / N ratio) of the pulse wave signal 22.

[0067] 9, when correcting the white balance 33, the control unit 14 increases the gain gG as the pre-setting representative value RVP(G) of the G channel calculated by the representative value calculation unit 12 before the gain gG is set decreases. Furthermore, when correcting the white balance 33, the control unit 14 increases the gain gB as the pre-setting representative value RVP(B) of the B channel calculated by the representative value calculation unit 12 before the gain gB is set decreases. For example, the control unit 14 sets the gain gR to 1, the gain gG to the ratio RVP(R) / RVP(G) of the pre-setting representative value RVP(R) to the pre-setting representative value RVP(G), and the gain gB to the ratio RVP(R) / RVP(B) of the pre-setting representative value RVP(R) to the pre-setting representative value RVP(B). This allows the control unit 14 to set the imaging conditions 21 so that the representative values ​​RV(G) and RV(B) approach the representative value RV(R). This makes it possible to increase the representative values ​​RV(R), RV(G), and RV(B) while preventing saturation of the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn). This makes it possible to increase the number of gradations that can be assigned to the time changes of the representative values ​​RV(R), RV(G), and RV(B). This makes it possible to accurately reflect the pulse wave in the representative values ​​RV(R), RV(G), and RV(B). This makes it possible to accurately reflect the pulse wave in pulse wave signal 22 calculated from the representative values ​​RV(R), RV(G), and RV(B).

[0068] 1.11 Quantization in the imaging section FIG. 10 is a block diagram of an imaging unit provided in the pulse wave signal acquiring device of the first embodiment.

[0069] As shown in FIG. 10, the imaging unit 11 includes an imaging element 61, an amplifier circuit 62, a quantization unit 63, an amplifier unit 64, and a conversion unit 65.

[0070] The image sensor 61 outputs pre-amplification pixel signals PS1(R1),...,PS1(Rn) of pixels R1,...,Rn, pre-amplification pixel signals PS1(G1),...,PS1(Gn) of pixels G1,...,Gn, and pre-amplification pixel signals PS1(B1),...,PS1(Bn) of pixels B1,...,Bn. The output pre-amplification pixel signals PS1(R1),...,PS1(Rn), PS1(G1),...,PS1(Gn), PS1(B1),...,PS1(Bn) are analog signals and represent continuous quantities. The image sensor 61 increases the pre-amplification pixel signals PS1(R1),...,PS1(Rn) as the received light amounts A(R1),...,A(Rn) increase. The image sensor 61 increases the pre-amplification pixel signals PS1(G1),...,PS1(Gn) as the received light amounts A(G1),...,A(Gn) increase. The image sensor 61 increases the pre-amplification pixel signals PS1(B1),...,PS1(Bn) as the received light amounts A(B1),...,A(Bn) increase. The image sensor 61 is a complementary metal-oxide semiconductor (CMOS) image sensor, a charge-coupled device (CCD) image sensor, or the like.

[0071] The amplifier circuit 62 amplifies the output pre-amplification pixel signals PS1(R1),...,PS1(Rn) by a gain g and outputs amplified pixel signals PS2(R1),...,PS2(Rn), respectively. The amplifier circuit 62 amplifies the output pre-amplification pixel signals PS1(G1),...,PS1(Gn) by a gain g and outputs amplified pixel signals PS2(G1),...,PS2(Gn), respectively. The amplifier circuit 62 amplifies the output pre-amplification pixel signals PS1(B1),...,PS1(Bn) by a gain g and outputs amplified pixel signals PS2(B1),...,PS2(Bn), respectively. The output amplified pixel signals PS2(R1),...,PS2(Rn), PS2(G1),...,PS2(Gn), PS2(B1),...,PS2(Bn) are analog signals and represent continuous quantities. The amplifier circuit 62 increases the amplified pixel signals PS2(R1),...,PS2(Rn), PS2(G1),...,PS2(Gn), PS2(B1),...,PS2(Bn) as the gain g increases. The amplifier circuit 62 increases the amplified pixel signals PS2(R1),...,PS2(Rn) as the pre-amplification pixel signals PS1(R1),...,PS1(Rn) increase. The amplifier circuit 62 increases the amplified pixel signals PS2(G1),...,PS2(Gn) as the pre-amplification pixel signals PS1(G1),...,PS1(Gn) increase. The amplifier circuit 62 increases the amplified pixel signals PS2(B1),...,PS2(Bn) as the pre-amplification pixel signals PS1(B1),...,PS1(Bn) increase.

[0072] The imaging element 61 and the amplifier circuit 62 constitute a pixel signal output section that outputs quantized amplified pixel signals PS2(R1),...,PS2(Rn),PS2(G1),...,PS2(Gn),PS2(B1),...,PS2(Bn).

[0073] The quantization unit 63 quantizes the output amplified pixel signals PS2(R1),...,PS2(Rn) and outputs pre-amplification pixel values ​​PV1(R1),...,PV1(Rn), respectively. The quantization unit 63 quantizes the output amplified pixel signals PS2(G1),...,PS2(Gn) and outputs pre-amplification pixel values ​​PV1(G1),...,PV1(Gn), respectively. The quantization unit 63 quantizes the output amplified pixel signals PS2(B1),...,PS2(Bn) and outputs pre-amplification pixel values ​​PV1(B1),...,PV1(Bn), respectively. The pre-amplification pixel values ​​PV1(R1),...,PV1(Rn),PV1(G1),...,PV1(Gn),PV1(B1),...,PV1(Bn) are represented by digital signals, are discrete values, and have a second bit length. The quantization unit 63 increases the pre-amplification pixel values ​​PV1(R1),...,PV1(Rn) as the post-amplification pixel signals PS2(R1),...,PS2(Rn) increase. The quantization unit 63 increases the pre-amplification pixel values ​​PV1(G1),...,PV1(Gn) as the post-amplification pixel signals PS2(G1),...,PS2(Gn) increase. The quantization unit 63 increases the pre-amplification pixel values ​​PV1(B1),...,PV1(Bn) as the post-amplification pixel signals PS2(B1),...,PS2(Bn) increase.

[0074] The amplifier 64 amplifies the output pre-amplification pixel values ​​PV1(R1),...,PV1(Rn) by a gain gR and outputs amplified pixel values ​​PV2(R1),...,PV2(Rn), respectively. The amplifier 64 amplifies the output pre-amplification pixel values ​​PV1(G1),...,PV1(Gn) by a gain gG and outputs amplified pixel values ​​PV2(G1),...,PV2(Gn), respectively. The amplifier 64 amplifies the output pre-amplification pixel values ​​PV1(B1),...,PV1(Bn) by a gain gB and outputs amplified pixel values ​​PV2(B1),...,PV2(Bn), respectively. The amplified pixel values ​​PV2(R1),...,PV2(Rn), PV2(G1),...,PV2(Gn), PV2(B1),...,PV2(Bn) are represented by digital signals, are discrete values, and have a second bit length. The amplifier 64 increases the amplified pixel values ​​PV2(R1),...,PV2(Rn) as the gain gR increases. The amplifier 64 increases the amplified pixel values ​​PV2(G1),...,PV2(Gn) as the gain gG increases. The amplifier 64 increases the amplified pixel values ​​PV2(B1),...,PV2(Bn) as the gain gB increases. The amplifier 64 increases the amplified pixel values ​​PV2(R1),...,PV2(Rn) as the pre-amplification pixel values ​​PV1(R1),...,PV1(Rn) increase. The amplifier 64 increases the amplified pixel values ​​PV2(G1),...,PV2(Gn) as the pre-amplification pixel values ​​PV1(G1),...,PV1(Gn) increase, respectively. The amplifier 64 increases the amplified pixel values ​​PV2(B1),...,PV2(Bn) as the pre-amplification pixel values ​​PV1(B1),...,PV1(Bn) increase, respectively.

[0075] The conversion unit 65 converts the output amplified pixel values ​​PV2(R1),...,PV2(Rn) into pixel values ​​PV(R1),...,PV(Rn), respectively. The conversion unit 65 converts the output amplified pixel values ​​PV2(G1),...,PV2(Gn) into pixel values ​​PV(G1),...,PV(Gn), respectively. The conversion unit 65 converts the output amplified pixel values ​​PV2(B1),...,PV2(Bn) into pixel values ​​PV(B1),...,PV(Bn), respectively. The pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) are represented by digital signals, are discrete values, and have a first bit length. The second bit length is longer than the first bit length. Therefore, the conversion unit 65 reduces the bit depth of the pixel values ​​from the second bit length to the first bit length.

[0076] The quantization unit 63, the amplification unit 64, and the conversion unit 65 collectively constitute a quantization unit that quantizes the amplified pixel signals PS2(R1),...,PS2(Rn),PS2(G1),...,PS2(Gn),PS2(B1),...,PS2(Bn) and converts them into pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn), respectively.

[0077] 1.12 Suppression of loss of pulse wave information In the imaging unit 11, a gain g used to adjust the gain 31 and the ISO sensitivity 32 is applied to the pre-amplification pixel signals PS1(R1),...,PS1(Rn), PS1(G1),...,PS1(Gn), PS1(B1),...,PS1(Bn) obtained before quantization. Furthermore, gains gR, gG, and gB used to correct the white balance 33 are applied to the pre-amplification pixel values ​​PV1(R1),...,PV1(Rn), PV1(G1),...,PV1(Gn), PV1(B1),...,PV1(Bn) obtained after quantization. In this case, focusing on the R channel, when the gain gR is not an integer, the pre-amplification pixel values ​​PV1(R1),...,PV1(Rn) are multiplied by the non-integer gain gR to obtain the amplified pixel values ​​PV2(R1),...,PV2(Rn), respectively. For this reason, an error may occur in the amplified pixel value PV2(Ri) deviating from the product of the pre-amplification pixel value PV1(Ri) and the gain gR. For example, if the pre-amplification pixel value PV1(Ri) is 3 and the gain gR is 0.5, the product of the pre-amplification pixel value PV1(Ri) and the gain gR, 3×0.5=1.5, is rounded to the integer 2 to become the amplified pixel value PV2(Ri). For this reason, an error may occur in the amplified pixel value PV2(Ri) deviating from the product of the pre-amplification pixel value PV1(Ri) and the gain gR. Furthermore, if the pre-amplification pixel value PV1(Ri) is 4 and the gain gR is 0.5, the product of the pre-amplification pixel value PV1(Ri) and the gain gR, 4×0.5=2, becomes the amplified pixel value PV2(Ri). That is, in both cases where the pre-amplification pixel value PV1(Ri) is 3 and where the pre-amplification pixel value PV1(Ri) is 4, the post-amplification pixel value PV2(Ri) is 2. This means that part of the information about the pulse wave contained in the pre-amplification pixel value PV1(Ri) is lost in the post-amplification pixel value PV2(Ri). Furthermore, when the pre-amplification pixel value PV1(Ri) is 4 and the gain gR is 1.2, the product of the pre-amplification pixel value PV1(Ri) and the gain gR, 4 × 1.2 = 4.8, is rounded to the integer 5 to become the post-amplification pixel value PV2(Ri). As a result, an error occurs in which the post-amplification pixel value PV2(Ri) deviates from the product of the pre-amplification pixel value PV1(Ri) and the gain gR. The same can be said when focusing on the G channel or the B channel.

[0078] Preferably, the control unit 14 sets the gain gG to an integer to avoid losing part of the information in the amplified pixel values ​​PV2(G1),...,PV2(Gn) obtained from the pre-amplified pixel values ​​PV1(G1),...,PV1(Gn), which contain a wealth of information about the pulse wave. For example, the control unit 14 sets the gain gR to RVP(G) / RVP(R) and the gains gG and gB to 1. As a result, the control unit 14 corrects the white balance 33 so that the representative values ​​RV(R) and RV(G) are approximately equal and the representative value RV(B) is smaller than the representative values ​​RV(R) and RV(G). The control unit 14 then adjusts the gain 31 and the ISO sensitivity 32 so that the pixel values ​​PV(R1),...,PV(Rn),PV(G1),...,PV(Gn),PV(B1),...,PV(Bn) are large enough to avoid saturation. This allows pulse wave signal 22 to accurately reflect information about the pulse wave that is abundantly contained in pixel values ​​PV(G1), . . . , PV(Gn).

[0079] 1.13 Estimating pixel values ​​before white balance correction FIG. 11 is a diagram showing the content of the processing performed by a representative value calculation unit provided in a pulse wave signal acquisition device according to a second modification of the first embodiment.

[0080] 11 , the representative value calculation unit 12 estimates estimated pixel values ​​PVE(Rp),...,PVE(Rq) from a gain gR and post-setting pixel values ​​PVQ(Rp),...,PVQ(Rq) output by the imaging unit 11 after the gain gR is set. The representative value calculation unit 12 also estimates estimated pixel values ​​PVE(Gp),...,PVE(Gq) from a gain gG and post-setting pixel values ​​PVQ(Gp),...,PVQ(Gq) output by the imaging unit 11 after the gain gG is set. The representative value calculation unit 12 also estimates estimated pixel values ​​PVE(Bp),...,PVE(Bq) from a gain gB and post-setting pixel values ​​PVQ(Bp),...,PVQ(Bq) output by the imaging unit 11 after the gain gB is set. The estimated pixel values ​​PVE(Rp),...,PVE(Rq) are estimates indicating the magnitude of the amplified pixel signals PS2(Rp),...,PS2(Rq) and are estimates of the pre-amplification pixel values ​​PV1(Rp),...,PV1(Rq). The estimated pixel values ​​PVE(Gp),...,PVE(Gq) are estimates indicating the magnitude of the amplified pixel signals PS2(Gp),...,PS2(Gq) and are estimates of the pre-amplification pixel values ​​PV1(Gp),...,PV1(Gq). The estimated pixel values ​​PVE(Bp),...,PVE(Bq) are estimates indicating the magnitude of the amplified pixel signals PS2(Bp),...,PS2(Bq) and are estimates of the pre-amplification pixel values ​​PV1(Bp),...,PV1(Bq). The pixel values ​​PV(Rp),...,PV(Rq),PV(Gp),...,PV(Gq),PV(Bp),...,PV(Bq) have a first bit length. The estimated pixel values ​​PVE(Rp),...,PVE(Rq),PVE(Gp),...,PVE(Gq),PVE(Bp),...,PVE(Bq) have a second bit length that is longer than the first bit length. The representative value calculation unit 12 estimates estimated pixel values ​​PVE(Rp),...,PVE(Rq),PVE(Gp),...,PVE(Gq),PVE(Bp),...,PVE(Bq) having a second bit length from set pixel values ​​PVQ(Rp),...,PVQ(Rq),PVQ(Gp),...,PVQ(Gq),PVQ(Bp),...,PVQ(Bq) having a first bit length by super-resolution processing or the like.Unlike the imaging unit 11, the representative value calculation unit 12 can handle pixel values ​​having a long bit length with high accuracy. By processing pixel values ​​having a second bit length that is longer than the first bit length, the representative value calculation unit 12 can prevent a portion of information related to the pulse wave from being lost.

[0081] The representative value calculation unit 12 calculates a representative value RV(R) from the estimated pixel values ​​PVE(Rp),...,PVE(Rq). The representative value calculation unit 12 calculates a representative value RV(G) from the estimated pixel values ​​PVE(Gp),...,PVE(Gq). The representative value calculation unit 12 calculates a representative value RV(B) from the estimated pixel values ​​PVE(Bp),...,PVE(Bq).

[0082] This allows pulse wave signal 22 to be obtained from estimated pixel values ​​PVE(Rp),...,PVE(Rq),PVE(Gp),...,PVE(Gq),PVE(Bp),...,PVE(Bq) having RGB ratios that reflect the actual color of human body HB before white balance 33 is corrected. Pulse wave signal 22 that accurately reflects the pulse wave can be obtained on a scale similar to that before white balance 33 is corrected.

[0083] FIG. 12 is a diagram showing the content of processing performed by a display control unit provided in a pulse wave signal acquiring device according to a third modification of the first embodiment.

[0084] 12 , the display control unit 15 estimates estimated pixel values ​​PVE(R1),...,PVE(Rn) from a gain gR and post-setting pixel values ​​PVQ(R1),...,PVQ(Rn) output by the imaging unit 11 after the gain gR is set. The display control unit 15 also estimates estimated pixel values ​​PVE(G1),...,PVE(Gn) from a gain gG and post-setting pixel values ​​PVQ(G1),...,PVQ(Gn) output by the imaging unit 11 after the gain gG is set. The display control unit 15 also estimates estimated pixel values ​​PVE(B1),...,PVE(Bn) from a gain gB and post-setting pixel values ​​PVQ(B1),...,PVQ(Bn) output by the imaging unit 11 after the gain gB is set. The estimated pixel values ​​PVE(R1),...,PVE(Rn) are estimates of the magnitude of the amplified pixel signals PS2(R1),...,PS2(Rn) and are estimates of the pre-amplification pixel values ​​PV1(R1),...,PV1(Rn). The estimated pixel values ​​PVE(G1),...,PVE(Gn) are estimates of the magnitude of the amplified pixel signals PS2(G1),...,PS2(Gn) and are estimates of the pre-amplification pixel values ​​PV1(G1),...,PV1(Gn). The estimated pixel values ​​PVE(B1),...,PVE(Bn) are estimates of the magnitude of the amplified pixel signals PS2(B1),...,PS2(Bn) and are estimates of the pre-amplification pixel values ​​PV1(B1),...,PV1(Bn).

[0085] The display control unit 15 displays frame images corresponding to the estimated pixel values ​​PVE(R1),...,PVE(Rn),PVE(G1),...,PVE(Gn),PVE(B1),...,PVE(Bn) on the display. This allows the display to display natural moving images having an RGB ratio that reflects the actual color of the human body HB before the white balance 33 is adjusted.

[0086] 1.14 Hardware FIG. 13 is a block diagram of a computer that functions as a representative value calculation unit, a pulse wave signal calculation unit, a control unit, and a display control unit provided in the pulse wave signal acquisition device of the first embodiment.

[0087] 13 includes a processor 81, a memory 82, and a storage 83. A pulse wave signal acquisition program 91 is installed in the storage 83.

[0088] The processor 81 is a central processing unit (CPU), a graphics processing unit (GPU), etc. The memory 82 is a random access memory (RAM), a read-only memory (ROM), etc. The storage 83 is a solid state drive (SSD), a hard disk drive (HDD), a flash memory, etc.

[0089] Processor 81 executes pulse wave signal acquisition program 91 loaded from storage 83 into memory 82, causing computer 71 to operate as representative value calculation unit 12, pulse wave signal calculation unit 13, control unit 14, and display control unit 15. All or part of the processing performed by computer 71 may be performed by dedicated electronic circuits.

[0090] Pulse wave signal acquisition program 91 is received via a network and recorded in storage 83, which is an internal recording medium. Alternatively, pulse wave signal acquisition program 91 is read from an external recording medium such as an optical disk, a magnetic disk, or a flash memory device, and recorded in storage 83, which is an internal recording medium.

[0091] 1.15 Processing flow FIG. 14 is a flowchart showing the flow of processing performed by the pulse wave signal acquiring device of the first embodiment.

[0092] Pulse wave signal acquiring device 1 executes steps S101 to S112 shown in Figure 14. Pulse wave signal acquiring device 1 sets imaging conditions 21 in steps S101 to S108, and calculates pulse wave signal 22 in steps S109 to S112.

[0093] In step S101, the control unit 14 sets the imaging conditions 21. At this time, the control unit 14 sets the imaging conditions 21 to default imaging conditions. In the default imaging conditions, the gains g, gR, gG, and gB are set to a reference gain of 1.

[0094] In the following step S102, control unit 14 causes imaging unit 11 to capture an image. As a result, imaging unit 11 captures an image and outputs a frame image. The output frame image includes pixel values ​​PV(R1), . . ., PV(Rn), PV(G1), . . ., PV(Gn), PV(B1), . . ., PV(Bn).

[0095] In the following step S103, the representative value calculation unit 12 sets the region of interest 41.

[0096] In the following step S104, the representative value calculation unit 12 extracts pixel values ​​PV(Rp),···,PV(Rq), PV(Gp),···,PV(Gq), PV(Bp),···,PV(Bq) of pixels Rp,···,Rq, Gp,···,Gq, Bp,···,Bq within the region of interest from pixel values ​​PV(R1),···,PV(Rn),PV(G1),···,PV(Gn),PV(B1),···,PV(Bn) of pixels R1,···,Rn, G1,···,Gn, B1,···,Bn.

[0097] In the following step S105, the representative value calculation unit 12 calculates representative values ​​RV(R), RV(G), and RV(B) from the pixel values ​​PV(Rp),...,PV(Rq),PV(Gp),...,PV(Gq),PV(Bp),...,PV(Bq).

[0098] In the following step S106, the control unit 14 determines whether the representative values ​​RV(R), RV(G), and RV(B) are equal to or greater than the set values ​​SV(R), SV(G), and SV(B), respectively. If it is determined that the representative values ​​RV(R), RV(G), and RV(B) are not equal to or greater than the set values ​​SV(R), SV(G), and SV(B), respectively, step S107 is executed. If it is determined that the representative values ​​RV(R), RV(G), and RV(B) are equal to or greater than the set values ​​SV(R), SV(G), and SV(B), respectively, step S109 is executed.

[0099] In step S107, the control unit 14 resets the imaging conditions 21. At that time, the control unit 14 resets the imaging conditions 21 to imaging conditions under which the representative values ​​RV(R), RV(G), and RV(B) are expected to be equal to or greater than the set values ​​SV(R), SV(G), and SV(B), respectively.

[0100] In step S108, control unit 14 causes imaging unit 11 to capture an image. As a result, imaging unit 11 captures an image and outputs a frame image. The output frame image includes pixel values ​​PV(R1), . . ., PV(Rn), PV(G1), . . ., PV(Gn), PV(B1), . . ., PV(Bn).

[0101] After step S108 is executed, step S104 is executed again.

[0102] Steps S101 to S108 continue to reset the imaging conditions 21 before the representative values ​​RV(R), RV(G), and RV(B) become equal to or greater than the set values ​​SV(R), SV(G), and SV(B), respectively, and after the representative values ​​RV(R), RV(G), and RV(B) become equal to or greater than the set values ​​SV(R), SV(G), and SV(B), respectively, steps S109 to S112 are executed.

[0103] In step S109, control unit 14 causes imaging unit 11 to repeatedly capture images. As a result, imaging unit 11 repeatedly captures images and outputs a plurality of frame images. Each of the output frame images includes pixel values ​​PV(R1), . . ., PV(Rn), PV(G1), . . ., PV(Gn), PV(B1), . . ., PV(Bn).

[0104] In the following step S110, the representative value calculation unit 12 extracts pixel values ​​PV(Rp),···,PV(Rq), PV(Gp),···,PV(Gq), PV(Bp),···,PV(Bq) of pixels Rp,···,Rq, Gp,···,Gq, Bp,···,Bq within the region of interest from pixel values ​​PV(R1),···,PV(Rn), PV(G1),···,PV(Gn), PV(B1),···,PV(Bn) of pixels R1,···,Rn, G1,···,Gn, B1,···,Bn for each of the multiple frame images.

[0105] In the next step S111, the representative value calculation unit 12 calculates representative values ​​RV(R), RV(G), and RV(B) from the pixel values ​​PV(Rp), . . . , PV(Rq), PV(Gp), . . . , PV(Gq), PV(Bp), . . . , PV(Bq) for each of the multiple frame images. In this way, the representative value calculation unit 12 calculates the changes over time in the representative values ​​RV(R), RV(G), and RV(B).

[0106] In the following step S112, pulse wave signal calculation unit 13 calculates pulse wave signal 22 from the changes over time in representative values ​​RV(R), RV(G), and RV(B).

[0107] 2. Second embodiment The following describes the differences between the second embodiment and the first embodiment. For points that are not described, the second embodiment also employs the same configuration as that employed in the first embodiment.

[0108] 2.1 Quantization in the imaging section

[0109] FIG. 15 is a block diagram of an imaging unit provided in a pulse wave signal acquiring device according to the second embodiment.

[0110] As shown in FIG. 15, the imaging unit 11 includes an imaging element 61, an amplifier circuit 62, and a quantization unit 63.

[0111] The imaging element 61 outputs pre-amplified pixel signals PS1(R1),...,PS1(Rn) of pixels R1,...,Rn, pre-amplified pixel signals PS1(G1),...,PS1(Gn) of pixels G1,...,Gn, and pre-amplified pixel signals PS1(B1),...,PS1(Bn) of pixels B1,...,Bn.

[0112] The imaging element 61 constitutes a pixel signal output section that outputs amplified pre-amplified pixel signals PS1(R1),...,PS1(Rn),PS1(G1),...,PS1(Gn),PS1(B1),...,PS1(Bn).

[0113] The amplifier circuit 62 amplifies the output pre-amplification pixel signals PS1(R1),...,PS1(Rn) with gains g and gR and outputs amplified pixel signals PS2(R1),...,PS2(Rn), respectively. The amplifier circuit 62 amplifies the output pre-amplification pixel signals PS1(G1),...,PS1(Gn) with gains g and gG and outputs amplified pixel signals PS2(G1),...,PS2(Gn), respectively. The amplifier circuit 62 amplifies the output pre-amplification pixel signals PS1(B1),...,PS1(Bn) with gains g and gB and outputs amplified pixel signals PS2(B1),...,PS2(Bn), respectively.

[0114] The quantization unit 63 quantizes the output amplified pixel signals PS2(R1),...,PS2(Rn) and outputs pixel values ​​PV(R1),...,PV(Rn), respectively. The quantization unit 63 quantizes the output amplified pixel signals PS2(G1),...,PS2(Gn) and outputs pixel values ​​PV(G1),...,PV(Gn), respectively. The quantization unit 63 quantizes the output amplified pixel signals PS2(B1),...,PS2(Bn) and outputs pixel values ​​PV(B1),...,PV(Bn), respectively.

[0115] 2.2 Estimating pixel values ​​before white balance correction FIG. 11 is also a diagram showing the content of the processing performed by the representative value calculation section provided in the pulse wave signal acquisition device of the first modified example of the second embodiment.

[0116] 11 , the representative value calculation unit 12 estimates estimated pixel values ​​PVE(Rp),...,PVE(Rq) from a gain gR and post-setting pixel values ​​PVQ(Rp),...,PVQ(Rq) output by the imaging unit 11 after the gain gR is set. The representative value calculation unit 12 also estimates estimated pixel values ​​PVE(Gp),...,PVE(Gq) from a gain gG and post-setting pixel values ​​PVQ(Gp),...,PVQ(Gq) output by the imaging unit 11 after the gain gG is set. The representative value calculation unit 12 also estimates estimated pixel values ​​PVE(Bp),...,PVE(Bq) from a gain gB and post-setting pixel values ​​PVQ(Bp),...,PVQ(Bq) output by the imaging unit 11 after the gain gB is set. The estimated pixel values ​​PVE(Rp),...,PVE(Rq) respectively indicate the magnitudes of the pre-set pixel signals PS2(Rp),...,PS2(Rq) output by the amplifier circuit 62 before the gain gR is set. The estimated pixel values ​​PVE(Gp),...,PVE(Gq) respectively indicate the magnitudes of the pre-set pixel signals PS2(Gp),...,PS2(Gq) output by the amplifier circuit 62 before the gain gG is set. The estimated pixel values ​​PVE(Bp),...,PVE(Bq) respectively indicate the magnitudes of the pre-set pixel signals PS2(Bp),...,PS2(Bq) output by the amplifier circuit 62 before the gain gB is set. The pixel values ​​PV(Rp),...,PV(Rq), PV(Gp),...,PV(Gq), PV(Bp),...,PV(Bq) have a first bit length. The estimated pixel values ​​PVE(Rp),...,PVE(Rq),PVE(Gp),...,PVE(Gq),PVE(Bp),...,PVE(Bq) have a second bit length that is longer than the first bit length. The representative value calculation unit 12 estimates the estimated pixel values ​​PVE(Rp),...,PVE(Rq),PVE(Gp),...,PVE(Gq),PVE(Bp),...,PVE(Bq) having the second bit length from the post-setting pixel values ​​PVQ(Rp),...,PVQ(Rq),PVQ(Gp),...,PVQ(Gq),PVQ(Bp),...,PVQ(Bq) having the first bit length by super-resolution processing or the like.

[0117] The representative value calculation unit 12 calculates a representative value RV(R) from the estimated pixel values ​​PVE(Rp),...,PVE(Rq). The representative value calculation unit 12 calculates a representative value RV(G) from the estimated pixel values ​​PVE(Gp),...,PVE(Gq). The representative value calculation unit 12 calculates a representative value RV(B) from the estimated pixel values ​​PVE(Bp),...,PVE(Bq).

[0118] This allows pulse wave signal 22 to be obtained from estimated pixel values ​​PVE(Rp),...,PVE(Rq),PVE(Gp),...,PVE(Gq),PVE(Bp),...,PVE(Bq) having RGB ratios that reflect the actual color of human body HB before white balance 33 is corrected. Pulse wave signal 22 that accurately reflects the pulse wave can be obtained on a scale similar to that before white balance 33 is corrected.

[0119] FIG. 12 is a diagram showing the content of processing performed by a display control unit provided in a pulse wave signal acquiring device according to a second modification of the second embodiment.

[0120] 12 , the display control unit 15 estimates estimated pixel values ​​PVE(R1),...,PVE(Rn) from a gain gR and post-setting pixel values ​​PVQ(R1),...,PVQ(Rn) output by the imaging unit 11 after the gain gR is set. The display control unit 15 also estimates estimated pixel values ​​PVE(G1),...,PVE(Gn) from a gain gG and post-setting pixel values ​​PVQ(G1),...,PVQ(Gn) output by the imaging unit 11 after the gain gG is set. The display control unit 15 also estimates estimated pixel values ​​PVE(B1),...,PVE(Bn) from a gain gB and post-setting pixel values ​​PVQ(B1),...,PVQ(Bn) output by the imaging unit 11 after the gain gB is set. The estimated pixel values ​​PVE(R1),...,PVE(Rn) indicate the magnitudes of the pre-set pixel signals PS2(R1),...,PS2(Rn) output by the amplifier circuit 62 before the gain gR is set. The estimated pixel values ​​PVE(G1),...,PVE(Gn) indicate the magnitudes of the pre-set pixel signals PS2(G1),...,PS2(Gn) output by the amplifier circuit 62 before the gain gG is set. The estimated pixel values ​​PVE(B1),...,PVE(Bn) indicate the magnitudes of the pre-set pixel signals PS2(B1),...,PS2(Bn) output by the amplifier circuit 62 before the gain gB is set.

[0121] The display control unit 15 displays frame images corresponding to the estimated pixel values ​​PVE(R1),...,PVE(Rn),PVE(G1),...,PVE(Gn),PVE(B1),...,PVE(Bn) on the display. This allows the display to display natural moving images having an RGB ratio that reflects the actual color of the human body HB before the white balance 33 is adjusted.

[0122] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that has the same effect, or a configuration that can achieve the same purpose. [Explanation of symbols]

[0123] 1 Pulse wave signal acquisition device, 11 imaging unit, 12 representative value calculation unit, 13 pulse wave signal calculation unit, 14 control unit, 15 display control unit, 21 imaging conditions, 22 pulse wave signal, 31 gain, 32 ISO sensitivity, 33 white balance, 41 region of interest, 51R, 51G, 51B range, 61 imaging element, 62 amplifier circuit, 63 quantization unit, 64 amplifier unit, 65 conversion unit, 71 computer, 81 processor, 82 memory, 83 storage, 91 pulse wave signal acquisition program, HB human body.

Claims

1. an imaging unit that performs imaging in accordance with imaging conditions and outputs pixel values ​​of a plurality of pixels in each of two or more channels that correspond to two or more different wavelength bands; a representative value calculation unit that calculates a representative value of each of the channels from pixel values ​​of a plurality of pixels in an area in which a living body is photographed, the pixel values ​​of the plurality of pixels being included in the pixel values ​​of the plurality of pixels; a control unit that sets the imaging conditions for each channel individually so that a representative value for each channel is equal to or greater than a set value for each channel, the set value being equal to or greater than a central value of a range in which pixel values ​​of the plurality of pixels can be taken; a biosignal calculation unit that calculates a biosignal from a representative value of the two or more channels; Equipped with The control unit determining whether the representative values ​​are equal to or greater than the set values; If it is determined that the representative values ​​are not equal to or greater than the set values, the imaging conditions are reset to imaging conditions that are expected to be equal to or greater than the set values, and the imaging unit is caused to perform imaging; The resetting of the imaging conditions is continued before the representative values ​​become equal to or greater than the set values, After the representative values ​​become equal to or greater than the set values, the biological signal acquiring device causes the imaging unit to repeatedly perform imaging.

2. The biological signal is a signal indicating a pulse wave. The biological signal acquiring device according to claim 1 .

3. the imaging conditions include a gain of each channel; the pixel values ​​of the plurality of pixels have a first bit length; The imaging unit a pixel signal output unit that outputs pixel signals of the plurality of pixels; a quantization unit that quantizes pixel signals of the plurality of pixels to obtain pre-amplified pixel values ​​of the plurality of pixels having a second bit length that is longer than the first bit length; an amplifier that amplifies pre-amplification pixel values ​​of the plurality of pixels by a gain of each channel to obtain amplified pixel values ​​of the plurality of pixels having the second bit length; a conversion unit that converts the amplified pixel values ​​of the plurality of pixels into pixel values ​​of the plurality of pixels; Equipped with The biological signal acquiring device according to claim 1 .

4. 4. The biological signal acquisition device of claim 3, wherein calculating a representative value of each channel from the pixel values ​​of the plurality of pixels within the region includes estimating estimated pixel values ​​of the plurality of pixels within the region, which are estimates of the pre-amplified pixel values ​​of the plurality of pixels within the region and have the second bit length, from the gain of each channel and the post-setting pixel values ​​of the plurality of pixels within the region output by the imaging unit after the gain of each channel has been set, and calculating a representative value of each channel from the estimated pixel values ​​of the plurality of pixels within the region.

5. a display control unit that estimates estimated pixel values ​​of the plurality of pixels, which are estimates of pre-amplification pixel values ​​of the plurality of pixels, from the gains of the respective channels and post-setting pixel values ​​of the plurality of pixels output by the imaging unit after the gains of the respective channels are set, and that displays an image corresponding to the estimated pixel values ​​of the plurality of pixels on a display; The biological signal acquiring device according to claim 3 .

6. the imaging conditions include a gain of each channel; The imaging unit a pixel signal output unit that outputs pixel signals of the plurality of pixels; an amplifier circuit that amplifies pixel signals of the plurality of pixels by a gain of each channel to obtain amplified pixel signals of the plurality of pixels; a quantization unit that quantizes the amplified pixel signals of the plurality of pixels to obtain pixel values ​​of the plurality of pixels; The biological signal acquiring device according to claim 1 .

7. the pixel values ​​of the plurality of pixels have a first bit length; Calculating the representative value of each channel from the pixel values ​​of the plurality of in-region pixels includes estimating estimated pixel values ​​of the plurality of in-region pixels, each of which indicates a magnitude of a pre-setting pixel signal of the plurality of in-region pixels output by the amplifier circuit before the gain of each channel is set, from the gain of each channel and post-setting pixel values ​​of the plurality of in-region pixels output by the imaging unit after the gain of each channel is set, and which have a second bit length longer than the first bit length, and calculating the representative value of each channel from the estimated pixel values ​​of the plurality of in-region pixels. The biological signal acquiring device according to claim 6 .

8. a display control unit that estimates estimated pixel values ​​of the plurality of pixels, each indicating a magnitude of a pre-setting pixel signal of the plurality of pixels output by the amplifier circuit before the gain of each channel is set, from the gain of each channel and post-setting pixel values ​​of the plurality of pixels output by the imaging unit after the gain of each channel is set, and displays an image corresponding to the estimated pixel values ​​of the plurality of pixels on a display; The biological signal acquiring device according to claim 6 .

9. Setting the imaging conditions includes changing the gains of the two or more channels from the reference gains of the two or more channels, respectively. The biological signal acquiring device according to any one of claims 3 to 8.

10. the two or more channels include a first channel and a second channel; Setting the imaging conditions includes setting a ratio of the gain of the second channel to the gain of the first channel, setting the gain of the first channel to a reference gain of the first channel, and setting the gain of the second channel to a product of the reference gain and the ratio. The biological signal acquiring device according to any one of claims 3 to 8.

11. The control unit sets the imaging conditions so that the representative values ​​of the two or more channels are close to each other. The biological signal acquiring device according to claim 1 .

12. the imaging conditions include a gain of each channel; Setting the imaging conditions so that the representative values ​​of the two or more channels become closer includes increasing the gain of a channel as the pre-setting representative value of the channel calculated by the representative value calculation unit before the gain of the channel included in the two or more channels becomes smaller. The biological signal acquiring device according to claim 11.

13. the two or more channels include a red channel, a green channel, and a blue channel; Setting the imaging conditions includes setting the gain of the red channel to 1, setting the gain of the green channel to a ratio of a pre-setting representative value of the red channel calculated by the representative value calculation unit before the gain of the red channel is set to a pre-setting representative value of the green channel calculated by the representative value calculation unit before the gain of the green channel is set, and setting the gain of the blue channel to a ratio of a pre-setting representative value of the red channel calculated by the representative value calculation unit before the gain of the blue channel is set. The biological signal acquiring device according to any one of claims 3 to 8.

14. The control unit sets the imaging conditions so that the representative value of each channel is equal to or less than an upper limit setting value of each channel, which is a value smaller than an upper limit value of a range that the plurality of pixel values ​​can take. The biological signal acquiring device according to claim 1 .

15. the representative value calculation unit may calculate, as the representative value of each channel, a first representative value of each channel and a second representative value of each channel that is different from the first representative value of each channel; setting the imaging conditions so that the representative value of each channel is equal to or greater than a set value of each channel includes setting the imaging conditions so that a first representative value of each channel is equal to or greater than a set value of each channel; Calculating the biological signal from the representative value of the two or more channels includes calculating the biological signal from a second representative value of the two or more channels. The biological signal acquiring device according to claim 1 .

16. Performing imaging according to imaging conditions and outputting pixel values ​​of a plurality of pixels in each of two or more channels corresponding to two or more different wavelength bands. and, pixel values ​​of a plurality of pixels in a region in which a living body is photographed, which are included in the pixel values ​​of the plurality of pixels; Calculating a representative value for each channel from setting the imaging conditions for each channel individually so that a representative value for each channel is equal to or greater than a set value for each channel, the set value being equal to or greater than a central value of a range in which pixel values ​​of the plurality of pixels can be taken; calculating a biological signal from a representative value of the two or more channels; In setting the imaging conditions, determining whether each of the representative values ​​is equal to or greater than the set value; If it is determined that each of the representative values ​​is not equal to or greater than the set value, the imaging conditions are reset to imaging conditions that are expected to be equal to or greater than the set value, and the imaging unit is caused to perform imaging; The resetting of the imaging conditions is continued before the representative values ​​become equal to or greater than the set values, After the representative values ​​become equal to or greater than the set values, the imaging unit is caused to repeatedly perform imaging.

17. causing the imaging unit to perform imaging in accordance with imaging conditions and outputting pixel values ​​of a plurality of pixels in each of two or more channels included in two or more channels respectively corresponding to two or more wavelength bands different from each other; calculating a representative value for each of the channels from pixel values ​​of a plurality of pixels in an area in which a living body is photographed, the pixel values ​​of the plurality of pixels being included in the pixel values ​​of the plurality of pixels; setting the imaging conditions for each channel individually so that a representative value for each channel is equal to or greater than a set value for each channel, the set value being equal to or greater than a central value of a range in which pixel values ​​of the plurality of pixels can be taken; calculating a biological signal from a representative value of the two or more channels; A biological signal acquisition program that causes a computer to execute the following: In setting the imaging conditions, determining whether the representative values ​​are equal to or greater than the set values; If it is determined that the representative values ​​are not equal to or greater than the set values, the imaging conditions are reset to imaging conditions that are expected to be equal to or greater than the set values, and the imaging unit is caused to perform imaging; The resetting of the imaging conditions is continued before the representative values ​​become equal to or greater than the set values, a biological signal acquisition program that causes the imaging unit to repeatedly capture images after the representative values ​​have reached or exceeded the set values;

18. an imaging unit that performs imaging in accordance with imaging conditions and outputs pixel values ​​of a plurality of pixels in each of two or more channels that correspond to two or more different wavelength bands; a representative value calculation unit that calculates a representative value of each of the channels from pixel values ​​of a plurality of pixels in an area in which a living body is photographed, the pixel values ​​of the plurality of pixels being included in the pixel values ​​of the plurality of pixels; a control unit that sets the imaging conditions so that a representative value of each channel is equal to or greater than a set value of each channel, the set value being equal to or greater than a central value of a range that pixel values ​​of the plurality of pixels can take; a biosignal calculation unit that calculates a biosignal from a representative value of the two or more channels; Equipped with The control unit determining whether the representative value is equal to or greater than the set value; If it is determined that the representative value is not equal to or greater than the set value, the imaging conditions are reset to imaging conditions that are expected to be equal to or greater than the set value, and the imaging unit is caused to perform imaging; The resetting of the imaging conditions is continued before the representative value becomes equal to or greater than the set value; After the representative value becomes equal to or greater than the set value, the imaging unit is caused to repeatedly capture images. the control unit sets the imaging conditions so that the representative value is equal to or greater than the set value and equal to or less than an upper limit set value of the channel; A biological signal acquiring device in which the size of the range from the set value to the upper set value is determined to be the same as the size of the range of change in pixel value due to body movement of a human body.

19. Performing imaging according to imaging conditions and outputting pixel values ​​of a plurality of pixels in each of two or more channels corresponding to two or more different wavelength bands. and, pixel values ​​of a plurality of pixels in a region in which a living body is photographed, which are included in the pixel values ​​of the plurality of pixels; Calculating a representative value for each channel from setting the imaging conditions so that a representative value of each channel is equal to or greater than a set value of each channel, the set value being equal to or greater than a central value of a range that pixel values ​​of the plurality of pixels can take; calculating a biological signal from a representative value of the two or more channels; In setting the imaging conditions, determining whether the representative value is equal to or greater than the set value; If it is determined that the representative value is not equal to or greater than the set value, the imaging conditions are reset to imaging conditions that are expected to be equal to or greater than the set value, and the imaging unit is caused to perform imaging; The resetting of the imaging conditions is continued before the representative value becomes equal to or greater than the set value; After the representative value becomes equal to or greater than the set value, the imaging unit is caused to repeatedly capture images. setting the imaging conditions so that the representative value is equal to or greater than the set value and equal to or less than an upper limit set value of the channel; A biological signal acquisition method, wherein the size of the range from the set value to the upper set value is determined to be the same as the size of the range of change in pixel value due to body movement of a human body.

20. causing the imaging unit to perform imaging in accordance with imaging conditions and outputting pixel values ​​of a plurality of pixels in each of two or more channels included in two or more channels respectively corresponding to two or more wavelength bands different from each other; calculating a representative value for each of the channels from pixel values ​​of a plurality of pixels in an area in which a living body is photographed, the pixel values ​​of the plurality of pixels being included in the pixel values ​​of the plurality of pixels; setting the imaging conditions so that a representative value of each channel is equal to or greater than a set value of each channel, the set value being equal to or greater than a central value of a range that pixel values ​​of the plurality of pixels can take; calculating a biological signal from a representative value of the two or more channels; A biological signal acquisition program that causes a computer to execute the following: In setting the imaging conditions, determining whether the representative value is equal to or greater than the set value; If it is determined that the representative value is not equal to or greater than the set value, the imaging conditions are reset to imaging conditions that are expected to be equal to or greater than the set value, and the imaging unit is caused to perform imaging; The resetting of the imaging conditions is continued before the representative value becomes equal to or greater than the set value; After the representative value becomes equal to or greater than the set value, the imaging unit is caused to repeatedly capture images. setting the imaging conditions so that the representative value is equal to or greater than the set value and equal to or less than an upper limit set value of the channel; A biological signal acquisition program in which the size of the range from the set value to the upper set value is determined to be the same as the size of the range of change in pixel value due to body movement of a human body.

Images