Pulse wave detection device and pulse wave detection program
A pulse wave detection device color converts a frame image of a moving image from RBG components to YIQ components, and identifies an eye section using the eye color of a user prepared in advance with a Q component. Next, the pulse wave detection device uses the Y values of the eye section to detect the brightness of the imaging environment. Then, the pulse wave detection device detects a pulse wave signal Qm on the basis of the average of the Q-values of a skin section in the frame image, corrects a change in the brightness by subtracting from Qm the average value Ye of the Y values of the eye section, and thereby outputs a post-brightness-correction Qm. As a result, a pulse wave can be successfully detected even if the brightness is changing because the user is moving in a vehicle or the like.
1. A pulse wave detection device comprising:
moving image obtaining means for obtaining a moving image photographing a region including a face of a target;
eye portion specifying means for specifying an eye portion of the target shown on the moving image;
brightness change obtaining means for obtaining a change in brightness caused by a change in a photographing environment of the moving image, by detecting a change in a predetermined color space component of the specified eye portion;
brightness correcting means for correcting the brightness of a skin portion of the target in a frame image of the moving image, or correcting the brightness of the entire frame image, using the change in the brightness obtained by the detecting of the change in the predetermined color space component of the specified eye portion;
pulse wave obtaining means for obtaining a pulse wave of the skin portion from a temporal change in the predetermined color space component in the skin portion after the brightness of the skin portion or of the entire frame image is corrected as above, the pulse wave being a wave travelling through the skin portion; and
output means for outputting the obtained pulse wave.
2. The pulse wave detection device according to claim 1 , further comprising:
skin portion specifying means for specifying the skin portion of the target shown on the obtained moving image, wherein
the pulse wave obtaining means obtains a pulse wave of the target from the temporal change of the predetermined color space component on the specified skin portion.
3. The pulse wave detection device according to claim 2 , further comprising:
reference component registration means for registering a reference component which is a color space component to be a reference for specifying the eye portion of the target, wherein
the eye portion specifying portion specifies a portion where the predetermined color space component corresponds to the registered reference component in the moving image as the eye portion.
4. The pulse wave detection device according to claim 2 , wherein
the skin portion specifying means specifies a portion where the predetermined color space component corresponds to the registered reference component in the moving image as the skin portion.
5. The pulse wave detection device according to claim 2 , wherein
the color space component used by the brightness change obtaining means for obtaining the change in brightness, the color space component used by the pulse wave obtaining means for obtaining the pulse wave, and the color space component used by the skin portion specifying means for specifying the skin portion are different color space components.
6. The pulse wave detection device according to claim 5 , wherein
the color space component used by the brightness change obtaining means for obtaining the change in brightness and the color space component used by the pulse wave obtaining means for obtaining the pulse wave are a brightness component (Y) and a chromaticity component (Q) of a YIQ color space made of the brightness component (Y) and the chromaticity components (I, Q), respectively; and
the color space component used by the skin portion specifying means for specifying the skin portion is a hue component (H) of an HSV color space made of the hue component (H), a saturation component (S), and a brightness component (V).
7. The pulse wave detection device according to claim 2 , further comprising:
color space converting means for converting a color space, wherein
the pulse wave obtaining means, the brightness change obtaining means, and the skin portion specifying means obtain a color space component in the color space obtained by converting the obtained moving image by the color space converting means.
8. The pulse wave detection device according to claim 3 , further comprising:
face image obtaining means for obtaining a face image obtained by photographing the face of the target; and
region specifying means for specifying a region of the eye in the face by face recognition processing in the obtained face image, wherein
the reference component registration means registers a color space component in the specified region as the reference component.
9. The pulse wave detection device according to claim 8 , wherein
the reference component registration means registers a value obtained by applying predetermined statistical processing to distribution of a color space component in the specified region as the reference component.
10. The pulse wave detection device according to claim 1 , wherein
the eye portion specifying means specifies the eye portion by the pixel values of the moving image.
11. The pulse wave detection device according to claim 1 , wherein
the brightness correcting means executes the correction by the pixel values of the moving image.
12. The pulse wave detection device according to claim 1 , wherein
the target is a passenger of transportation equipment, and monitoring means for monitoring a physical condition of the passenger by using the output pulse is provided.
13. A non-transitory computer readable medium storing thereon a pulse wave detection program for realizing by a computer:
a moving image obtaining function of obtaining a moving image photographing a region including a face of a target;
an eye portion specifying function of specifying an eye portion of the target shown on the moving image;
a brightness change obtaining function of obtaining a change in brightness caused by a change in a photographing environment of the moving image, by detecting a change in a predetermined color space component of the specified eye portion;
a brightness correcting function of correcting the brightness of a skin portion of the target in a frame image of the moving image, or correcting the brightness of the entire frame image, using the change in the brightness obtained by the detecting of the change in the predetermined color space component of the specified eye portion;
a pulse wave obtaining function of obtaining a pulse wave of the skin portion from a temporal change in the predetermined color space component in the skin portion after the brightness of the skin portion or of the entire frame image is corrected as above, the pulse wave being a wave travelling through the skin portion; and
an output function of outputting the obtained pulse wave.