Abstract: An image processing circuit capable of carrying out high-speed processing and improving the horizontal and vertical resolutions even with its simple structure. The pixel values a to i of a total of nine pixels, three pixels in the horizontal direction along a scanning line by three pixels in the vertical direction in which the line and adjacent lines are abreast, are extracted by a pixel value extracting section. The pixel values A1 to A4 of four pixels Q1 to Q4 generated additionally around the center pixel P5 are determined by calculation by a pixel value calculation section. These pixel values are outputted in units of one scanning line by correlating them with two scanning lines by a pixel value output section.

Abstract: A digital-to-analog converter for generating output waveforms with less distortion without the need for high-speed components. The digital-to-analog converter comprises a D/A converter, four voltage holding sections, four step function waveform generators, a voltage summing section, two integrators and a timing controller. The voltages corresponding to four sequential digital data inputs are held in the voltage holding sections, respectively, and the step function generators generate step function waveforms at the voltage levels corresponding to the held voltages. The voltage summing section combines the step function waveforms generated in the step function waveform generators, and two integrators integrate this combined waveform two times, thus producing a continuous analog voltage composed of the input digital data.

Abstract: A data interpolating system by which the operating quantity can be decreased and no truncation error is produced. A data processor comprises a discrete value extracting section 10, a sampling function operating section 20, and a convolution operating section 30 so as to perform interpolation between discrete values. The discrete value extracting section 10 extracts just previous four value from successively inputted discrete data, and the sampling function operating section 20 calculates, when the data interpolating position is specified, the value of the interpolating position based on the distances between the data interpolating position and the discrete values by using a sampling function of local support which can be differentiated only once over the whole region. The convolution operating section 30 multiplies the values of the four sampling functions by the discrete values, and adds up the products, thus performing convolution operation and outputting the interpolation value.

Abstract: A data interpolating method capable of reducing an operation volume without the occurrence of a truncation error. Each of four step function generators generates a preset step function. Multipliers each multiply step function values output from relative step function generators by discrete data values held cyclically in data holding sections. An adding unit adds together the multiplied results output from respective multipliers in response to the respective four discrete data and the added values is integrated twice by integrators, an interpolation value between the discrete data being then output from the second-stage integrator.

Abstract: A digital-analog converter for producing less distorted output waveforms without the need for an increase in the operating speed of components. A D/A converter 1 comprises a memory 10, an address counter 12, a B spline function generation circuit 14, four sampling function generation circuits 16, three delay circuits 18, four amplifiers 20, and three adding circuits 22, 24 and 26. Four items of digital data supplied one after another in the predetermined time interval T are stored in the memory 10. The gain of each of the four amplifiers 20 is set according to the corresponding digital data. The four sampling function generation circuits 16 generate signal waveforms of the sampling function, which appear individually in points a time T away from one another. The signal waveforms are amplified in the amplifier 20 and added to produce an analog signal associated with the interpolation value.

Abstract: A digital-to-analog converter for generating output waveforms with less distortion without the need for high-speed components. The digital-to-analog converter comprises four data holding sections, four step function generators, an adding section, a D/A converter, two integrators and a timing controller. Four digital data successively inputs are held in the data holding sections, respectively, and the step function generators generate step function whose values corresponding to the held data. The adding section sums the step functions generated in the step function generators, and the D/A converter generates the analog stepwise voltage corresponding to the summed value. The two integrators integrate this combined waveform two times, thus producing a continuous analog voltage that connects the input digital data smoothly.

Abstract: A sampling function generator capable of providing continuous output corresponding to a sampling function. The sampling function generator 1 comprises a B spline function generation circuit 10, delay circuits 12 and 14, inverting amplifiers 16 and 18, and adding circuits 20 and 22. The B-spline function generation circuit 10 continuously produces signal waveforms according to a third order B spline function. After delayed by predetermined time or attenuated to 1/4 amplitude and inverted, the signal waveforms are combined in the adding circuits 20 and 22 to form a signal waveforms of a sampling function that is differentiable once over the range and has values of local support.

Abstract: A method of compressing inputting two-dimensional object, compressing the two-dimensional data in a short time to a small amount of data and reproducing in any size at any position. This invention reads two dimensional object, e.g. characters, figures, drawings or Illustrations optically, extracts peripheral points from a binary image, approximates the peripheral lines by Fluency functions, reckons curvatures at all points, and finds joints. The peripheral points series are divided by the joints. The lines between two neighboring joints are approximated by straight lines, arcs and free curves in this order. The free curves are approximated by linear combinations of Fluency functions. Adoption of joints greatly alleviates the quantity of data. Approximation by Fluency functions heightens the quality of the reproduced objects.

Abstract: A video signal processing system improves the image quality displayed in a CRT or printed by a video printer. In order to produce natural and fine video signals, pixel data corresponding to an intermediate position between two neighboring pixels, are produced from pixel data of the neighboring two pixels. The pixel data corresponding to the intermediate position is produced by a convolution operation with respect to the pixel data of the two neighboring pixels and a quantized value of an impulse response signal.

Abstract: A signal modification circuit receives an input signal and produces an output having a modified characteristic. When the signal modification circuit is embodied in an audio circuit receiving an analog audio signal having a first variant level at its input, the audio circuit produces an output signal having a second variant level in which a frequency characteristic in a high frequency range is modified so that the second variant level decreases in accordance with a function of l/fm (f being frequency and m being an integer determined depending upon the nature of the audio signal) relative to the first variant level while being trapped in selected discrete frequencies. For this purpose a combination of a low-pass filter and a plurality of trap filters connected in series with one another, or a combination of a low-pass filter and a plurality of band-pass filters connected in parallel to one another.

Abstract: A data generator generates digital data at a sampling time interval .sub..DELTA. T (sampling frequency f.sub.s =1/.DELTA.T), and the three latest items of digital data V.sub.-1, V.sub.0, V.sub.+1 are repeatedly latched successively in three latch circuits every 3.multidot..sub..DELTA. T. A pulse response signal generator outputs unit pulse response signals of period 3.multidot..sub..DELTA. T at the time interval .multidot..sub..DELTA. T, and three multiplying-type DA converters multiply these three unit pulse response signals .phi..sub.0 (t+.sub..DELTA. T), .phi..sub.0 (t), .phi..sub.0 (t-.sub..DELTA. T) by the digital data V.sub.-1, V.sub.0, V.sub.+1, respectively, at a speed of a.multidot.f.sub.s (a times in time .sub..DELTA. T). The outputs of these multiplying-type DA converters are combined into an analog signal S.sub.A, which is delivered as an output.

Abstract: A continuous analog signal is produced by successively generating digital data V.sub.K (K=. . . , -4, -3, -2, -1, 0, 1, 2, 3, . . . ) every predetermined sampling period T, repeatedly generating, successively at a period 3T, signals .phi.(t+T), .phi.(t), .phi.(t-T), where a unit pulse response signal .psi.(t) is expressed by.psi.(t)=.SIGMA.A.sub.K .multidot..phi.(t-K.multidot.T) (K=-.infin..about.+.infin.)using a signal .phi.(t) (0.ltoreq.t.ltoreq.3.multidot.T) expressed by three piecewise polynomials, computing C in accordance with the equationC=.SIGMA.A.sub.-K .multidot.V.sub.K (K=-M.about.m)every sampling period T, where V.sub.0 represents digital data prevailing at the present time, cyclically storing the results of computation as C.sub.-1, C.sub.0, C.sub.1 in successive fashion, and converting the digital data into an analog quantity in accordance with the equationC.sub.-1 .multidot..phi.(t+T)+C.sub.2 .multidot..phi.(t)+C.sub.3 .multidot..phi.

Abstract: An image processor which can accurately and promptly obtain information about a ventricle of a living body, such as the boundary diagram, the volume, the centroid movement view and a three-dimensional view. An X-ray projection of a part to be diagnosed is quantized. The boundary and centroid of the part are obtained from the optimal ternary data using the variance of the gray-level of the image and the separation degree of a histogram. The volume and three-dimensional view of the part are obtained from this data using the gray-level method.