We have designed a new body surface isopotential mapping system under 8-bit microprocessor control. In this system, ECG data of 96 lead points on the human body surface are simultaneously held with 96 S/H circuits, amplified 60 dB with 96 AC amplifiers, scanned by multiplexers at a rate of 10, μsec/channel, digitized through an A-D converter into 10 bits, and stored in the data area (48 kilobytes' RAM). This process is repeated 250 times at an appropriate time interval of either 1, 2 or 4 msec, and all the ECG data are stored in the data area. After compensation of DC potential superimposed on the stored ECG data, isopotential maps are constructed from 87 out of 96 ECGs by use of a linear interpolation method. Both 12 lead ECGs and Frank lead VCGs of the same cardiac cycle as is used for construction of the maps, are also obtained from some of the 87 ECGs and the remaining 8 ECGs. Generation of maps, scalar ECGs and vector loops as well as their digital formats, can be displayed on a CRT within 20 minutes after the beginning of electrode placement on the body surface. If necessary, all the stored ECG data can be recorded on a cassette magnetic tape for permanent data storage. In addition, four kinds of data acquisition mode (Regular, Irregular, Next, and Precede) are designed for the selection of any required cardiac cycle of various arrhythmias. In conclusion, besides being downsized and cost-efficient because of the microcomputer incorporated, this system also has several advantage for clinical use, namely, data acquisition, map generation, and reduced time for data output.

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Amplitudes of visually evoked cortical potentials, VECP, are so small that they are not detectable without some method to eliminate the noise from the measurement system, including spontaneous brain waves.
In the present study, the Kalman filtering technique combined with the averaging procedure has been tried to estimate the real value of VECP amplitudes in response to checkerboard pattern stimuli in sinusoidal counterphase modulation.
It was found that the necessary times of summation for measurable VECPs decreased markedly. The error of the variance in the noise had no effective influence on results.
Differing from the Wiener filtering, it showed that the calculation of power spectra was not necessary and, moreover, the gain matrix could be computed beforehand. These advantageous factors enabled the shortening of the computation time for the Kalman filtering.

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To make the presently available lower prosthesis more physiological and to further improvethe adaptive capability of prosthetic gait, some sort of sensory feedback system must be supplemented to it.
The authors have developed sensory feedback system which transmits information received by the sensors fixed at the shoe sole and the knee part of the above knee prosthesis to the stump by means of the electric stimulation.
Upon evaluation by the amputee, a certain effectiveness of this system has been confirmed.
In this paper, structure of the device for this system is fully explained.

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This paper deals with a system and a method by which echo signals of M-mode echocardiogram obtained using a conventional ultrasonic diagnostic instrument are stored in a video tape and the echo signals transferred to a minicomputer directly from the instrument or through the video tape are processed automatically. For these purposes, a special interface circuit is equipped to connect the ultrasonic instrument to the minicomputer and the video tape recorder, and the emission of a burst of ultrasound is synchronized with the external timing pulse. Using this system the M-mode echocardiogram stored in the video tape can be repeatedly displayed on the oscilloscope of the instrument.
The M-mode echocardiogram for about 1.6 seconds is usually digitized in 256×200 pixels with 8-bit gray level and used as an image to be processed by the minicomputer. After detecting the positions of cardiac structures, i. e., interventricular septum and endocardium and epicardium of the posterior wall of the left ventricle, cardiac information, such as on the change of wall thickness, velocity of circumferential fibre shortening, volume change of the, left ventricle and So on, is obtained. Some clinical results are also shown.

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A cineangiocardiography for the left ventricle is highly helpful in examining the cardiac function. Quantitative information, such for example, as the volume change and wall motion of the left ventricle in the cardiac cycle, are unobtainable without detecting boundaries of the left ventricle on the consecutive frames of a cineangiocardiogram.
This paper deals with a heuristic method to detect the boundary of the left ventricle automatically and methods of displaying various cardiac functions with the aid of a minicomputer system.
Boundaries are detected from 80 to 120 consecutive frames of the cineangiocardiogram. In detecting a specific boundary, the boundary of the preceding frame is used to obtain overall information. This makes a stable detection possible.
By using the detected boundaries of the left ventricle, quantitative information various kinds on the cardiac function are obtained. The volume change, the wall motion, the %-shortening and so on, are calculated and displayed on the graphic display. Moreover, the motion of the boundary of the left ventricle is displayed on a CRT as a moving picture.
With the use of the system described in this paper, we can grasp the movement of the left ventricle exactly and the cardiac function quantitatively.

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Man's standing posture is stabilized by visual, vestibular, proprioceptive and other sensors which construct multi-feedback loops. In order to clarify the basic mechanism of such complicated posture control system, it is important to analyse the role and relation of each sensor.
We have already developed a servo-controlled force plate that is horizontally movable following arbitrary wave form. By means of this force plate, random disturbances were given to a subject and ankle joints moment was measured. The sway angles of the body and the legs were also measured with an ITV.
Processing the responses, we found the frequency characteristics of the posture control system. Using the simplified model, the results are discussed from a view-point of control engineering.

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Clumps of adenocarcinoma are found in about 10% of cytologically positive findings in mass screening of uterine cancer. Since they are not easily dispersed into individual cells, prescreening machines designed to examine individual cells fail to detect their presence. This paper presents two feature extraction methods, global and local, for the recognition of such cell clumps. The global feature extraction method is designed for prescreening machines, to extract two features utilizing digital image processing. One feature is an Euler number. A thresholded binary image is shrunk and propagated, so that only large objects corresponding to cell clumps remain. The Euler number of the remaining objects is a good measure of overlap of nuclei, one of morphological features of adenocarcinoma cell clumps. Another extracted feature is a correlation coefficient of binary images obtained at two different threshold levels. This value indicates the interior structure of the object, such as the amount of cytoplasm. Experiments using 79 samples, consisting of adenocarcinoma cell clumps, normal cell clumps, white blood cell clumps, and dust particles, yielded good results : i.e., false negative proved zero and false positive rate was 11%. The local feature extraction method is intended to examine the correspondence between morphological features described by medical doctors and the parameters extracted by machine. In this method each individual nucleus of a cell clump is examined. The center points and the radii of nuclei are computed by the process based mostly on the distance transformation for binary images. The variation in the distribution of radius and minimum distance among nuclei shows a good correspondence with the morphological features, i. e., irregularity of nuclear size, and irregularity of distance among nuclei.

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