A method for detecting human skin and identifying the surface condition of it using the three-phase spectral
matching imager (3PSMI) is proposed. The 3PSMI produces correlations pixel-wise between the spectrum of
an unknown object and an orthonormal pair of known reference spectra by use of the correlation image sensor
(CIS), and outputs the result as a complex image at an ordinary video frame rate, thus realizing both real-time
operation and high spectral resolution. In order to apply the 3PSMI to human skin, two tasks-discrimination
between skin and non-skin objects and evaluation of the degree of suntan and congestion on skin-are considered
and methods of generating an orthonormal pair of reference spectra for these tasks are proposed. Experiments
on these tasks are carried out on the developed 3PSMI with the reference spectra generated by the proposed
We propose a three-phase spectral matching imager (3PSMI) to realize a novel spectral matching method called quadrature spectral matching (QSM) in real time. The 3PSMI is comprised of the correlation image sensor (CIS) and wavelength-swept monochromatic illumination (WSMI) to perform QSM at each pixel on the CIS at a video frame rate. QSM consists of spectral correlation between an ac component of an object spectrum and an orthonormal pair of reference spectra, being equivalent to projecting the ac object spectrum onto a two-dimensional subspace spanned by the reference spectra. Similarity of the ac object spectrum to the reference spectra is evaluated in terms of the azimuth angle of the projection, independently of the norm of the ac object spectrum as well as spatial intensity distribution of the WSMI. A programable spectral light source is employed to implement the WSMI so that the spectral characteristics of the WSMI and CIS cancel each other and thus do not affect QSM on the 3PSMI. Experimental results confirm that the developed 3PSMI system can distinguish objects with smaller difference in spectral reflectance in real time than RGB imaging with off-the-shelf cameras.
The accuracy of stereo matching depends on precise detection of corresponding points in a pair of stereo images by
template matching. A multiband imaging system captures more than three channels in a visible range. The multiband
imaging technique is useful for improving the accuracy of the stereo matching. This paper proposes an imaging system
and an algorithm for stereo matching based on multiband images. The imaging system is composed of a liquid-crystal
tunable filter and a high sensitive monochrome camera. This imaging system has the advantage that low contrast color
textures that are lost in RGB images could be detected in the multiband-spectral images. We use a modified sequential
similarity detection algorithm (SSDA) for the acceleration of multiband template matching. The similarity is calculated
for each band in the descending order of the variance in template. The template matching is accelerated by quick
discontinuance of the calculation at dissimilar points. Experimental results show that multiband stereo matching is
accurate in comparing with RGB stereo matching. Measurement targets were sheets of color texture patches with small
color differences. The rate of detection of correct corresponding points was 98.4% by multiband stereo matching, while
the rate was 34.7% by RGB stereo matching. Moreover, use of the modified SSDA reduced the CPU time.
This paper proposes a spectral matching imager with a novel three-phase quadrature detection method. The
proposed imager consists of the time-domain correlation image sensor (CIS) and a high-speed programmable
spectral light source (PSLS) to produce the correlations between each of a quadrature pair of reference spectral
functions and spectral functions of objects. This is realized by modulating the object spectra into temporal
signals with the PSLS and then producing temporal correlations with reference signals at each pixel of the CIS.
The object that has the same spectral function as the target spectral function is detected as a vector with
an azimuthal angle of zero projected onto the two-dimensional (2-D) space spanned by the reference spectral
functions. The proposed method can estimate the correlation coefficient between the object and reference spectra
more reliably in a 2-D space than previous 1-D spectral matching methods, by factoring out the norm of the
object spectral function. Experimental results for a color chart confirm the effectiveness of the proposed method.
Three-dimensional (3D) modeling of object from two-dimensional (2D) image is important for many fields including
computer graphics, image understanding and medical imaging. Shape-from-Shading is a popular method for 3D shape
estimation from one image. For the 3D mesh generation, Delaunay triangulation is effective. If depths for all pixels in
an image are estimated by Shape-from-Shading and 3D Delaunay triangulation is done for the depth data, it is not
efficient. We propose an efficient method to generate 3D near-equilateral triangular mesh from 2D image directly. In the
proposed method, the projection of 3D mesh on 2D image is generated by ellipsoidal bubble mesh method firstly. Then,
the positions of mesh vertices in 3D space are estimated from Lambertian model and the direction of axes of ellipsoidal
bubble in ellipsoidal bubble method. We evaluated the proposed method by 3D mesh generation for a simulation image
and a picture taken by a digital camera. The results showed good estimation for the shapes of objects.
A method is proposed for estimating the spectral reflectance of made-up skin color under various conditions including the undesirable colored skin. The color of dark spot is caused by increasing the component of melanin. The reddish skin is caused by the increase of hemoglobin. Our method uses the Kubelka-Munk theory to calculate the surface spectral reflectance human skin. This theory calculates the reflectance and transmittance of the light passing through a turbid medium from the absorption and scattering of the medium. The spectral reflectance of made-up skin is estimated by adjusting parameters of the thickness of the makeup layer. The proposed estimation method is evaluated on an experiment in detail. First, we measure the spectral reflectance of facial skin under the three conditions of normal skin, undesirable skin, and made-up skin. The undesirable skin includes stain, suntan or ruddy skin. The made-up skin means the skin with foundation on the normal skin, the stain, the suntan and the ruddy skin. Second, we estimate the spectral reflectance of made-up skins from the reflectance of bare skins and optical characteristics of foundations. Good coincidence between the estimated reflectance and the direct measurement shows the feasibility of the proposed method.
Nowadays, there are many families that live separately. Especially, communication with elderly person living alone is very important. We propose a new tele-surveillance system to support of their communications and to give an alarm for the accident on the elderly person living alone. The systems are set on two sites; the room for the elderly person living alone and the living room of his/her family's house. This system tracks the persons in real-time and analyzes the person's condition. Then, the system transmits the information of their head position and their condition to another site. The computer of recipient site generates the computer graphics (CG) animation of the tracked person (avatar) and display on a monitor. This method reduces traffic on network and keeps the privacy for the tracked person. The tracking part of this system uses the omni-directional image sensor that can capture a surrounding image in whole direction at a time by using a hyperbolic mirror and a video camera. The system detects the person's head in images captured by omni-directional image sensors. Then, the position of the person’s head in a room is computed. We made a prototype system of this proposed system with graphical user interface using touch panels. Experiments and evaluations showed good feasibility of the proposed system.
The present paper describes a new indoor surveillance system for detection of an accident, such as fall or fit, happened to an aged single person. This system uses two types of cameras. One of them is the omni-directional image sensor for the tracking of the person’s position and detection of fall, and another is the controllable camera for capturing the detail of the person’s condition. The system detects points of the person’s head in images captured by some omni-directional image sensors, firstly. Then, a position of the person’s head in a room is computed from the points of person’s head in the images. When the person stops, the system classifies the person's pose into standing, sitting or lying according to the person's height. Then, the system judges that the accident has happened or not from the person’s pose, position and action. We made a prototype system with three omni-directional image sensors and a controllable camera. Then, we set the system in our laboratory’s room and experimented with the system. The implemented system detected the person’s position with the frame rate of 6 fps. In experiments, the error of position detection was 18 cm on the average. The error didn’t give serious influence to the control of the controllable camera. The error of height estimation was 6.9 cm. The conditions played by subjects were distinguished correctly.
The present paper describes a method for modeling human skin coloring and estimating the surface-spectral reflectance by using the Kubelka-Munk theory. First, human skin is modeled as two layers of turbid materials. Second, we describe the reflectance estimation problem as the Kubelka-Munk equations with unknown six parameters. These parameters are the regular reflectance at skin surface and the five weights for spectral absorption of such different pigments as melanin, carotene, oxy-hemoglobin, deoxy-hemoglobin, and bilirubin. Moreover, the optical coefficients of spectral absorption and scattering for the two skin layers and the thickness values of these layers are used for the solution. Finally, experiments are done for estimating the skin surface-spectral reflectance on some body parts, such as the cheeks of human face, the palm, the backs of hand, the inside of arm, and the outside of arm. It is confirmed that the proposed method is more reliable in all cases.