Biological information measuring apparatus and biological information measuring method, and computer program product

A biological information measuring method comprising:

• calculating a difference, at a mutually same time, between an image-based photoplethysmogram extracted from luminance information of a picture signal of a designated region of interest that is a skin region on a face, an arm or a hand of a subject included in a picture and an image-based photoplethysmogram extracted from luminance information of a picture signal of a further designated region of interest that is a skin region on the face, the arm or the hand of the subject other than the designated region of interest;
• calculating at least one of a pulse transit time or an instantaneous phase difference from the difference calculated;
• and
• measuring a fluctuation of a blood pressure of the subject on basis of the difference calculated, wherein
• the measuring includes performing a measuring process in accordance with a combination of the regions of interests from which the image-based photoplethysmograms are extracted and based on a correlation between the at least one of the pulse transit time or the instantaneous phase difference and the fluctuation of the blood pressure, the correlation being a positive correlation or a negative correlation, and, when a combination of the regions of interests from which the image-based photoplethysmograms are extracted, the correlation is either a combination of any of first regions of interest, in which, due to a peripheral arteriole being under control of a sympathetic nerve when the blood pressure increases, a first delay in an arrival of a first pulse wave is greater than a threshold, or, when a combination of any of second regions of interest from which the image-based photoplethysmograms are extracted, in which, due to a peripheral arteriole being under control of the sympathetic nerve and a parasympathetic nerve when the blood pressure increases, a second delay in an arrival of a second pulse wave is less than the first delay in the first regions of interest.

A computer program product having a non-transitory computer readable medium including a biological information measuring program, wherein the biological information measuring program, when executed by a computer, causes the computer to perform:

• calculating a difference, at a mutually same time, between an image-based photoplethysmogram extracted from luminance information of a picture signal of a designated region of interest that is a skin region on a face, an arm or a hand of a subject included in a picture and an image-based photoplethysmogram extracted from luminance information of a picture signal of a further designated region of interest that is a skin region on the face, the arm or the hand of the subject other than the designated region of interest;
• calculating at least one of a pulse transit time or an instantaneous phase difference from the difference calculated;
• performing a measuring process in accordance with a combination of the regions of interests from which the image-based photoplethysmograms are extracted and based on a correlation between the at least one of the pulse transit time or the instantaneous phase difference and the fluctuation of the blood pressure, the correlation being a positive correlation or a negative correlation, and when a combination of the regions of interests from which the image-based photoplethysmograms are extracted, the correlation is either a combination of any of first regions of interest in which, due to a peripheral arteriole being under control of a sympathetic nerve when the blood pressure increases, a first delay in an arrival of a first pulse wave is greater than a threshold, or, when a combination of any of second regions of interest from which the image-based photoplethysmograms are extracted, in which, due to a peripheral arteriole being under control of the sympathetic nerve and a parasympathetic nerve when the blood pressure increases, a second delay in an arrival of a second pulse wave is less than the first delay in the first regions of interest;
• and
• measuring the fluctuation of the blood pressure of the subject by processing the difference using the measuring process.