Abstract: A lighting system for plant cultivation comprises a light source, a light source driving unit that drives the light source, and a control unit that transmits a pulse signal to the light source driving unit. The control unit comprises a first pulse generating unit that generates a first pulse signal (S1) of a predetermined frequency, a second pulse generating unit that generates a second pulse signal (S2) of a frequency different from the predetermined frequency, and a pulse signal selecting unit that selects any one of the first pulse signal (S1) and the second pulse signal (S2) to transmit the selected one to the light source driving unit.

Abstract: The lighting system for plant cultivation (9) according to the present invention is configured to be capable of switching between an intermittent lighting mode and a continuous lighting mode. The intermittent lighting mode is a mode in which a light source emits light with a lighting cycle comprising a light period of turning on the light source for a predetermined time period and a dark period of turning off the light source for a predetermined time period. The continuous lighting mode is a mode in which the light source continuously emits light. In another aspect, the lighting system for plant cultivation (9) comprises a light source (3), a light source driving unit (2) that drives the light source (3), and a control unit (1) that transmits a pulse signal to the light source driving unit (2).

Abstract: A blood flow measurement system for measuring blood flow rate and blood flow velocity comprises a circuit device for irradiating an in vivo tissue measurement subject with coherent light, a light receiving element for receiving scattered light from the in vivo tissue, a converter for converting an intensity of the received scattered light into an electric signal, a circuit device for calculating a power spectrum of the time-course variation of the scattered light intensity, a device for plotting the power spectrum in a semilogarithmic coordinate system having a logarithmic vertical axis, and a device for linearly approximating a prescribed frequency component of the semilogarithmic power spectrum and calculating a slope and a y intercept of the power spectrum curve. The blood flow velocity can be determined from the slope of the curve approximating the power spectrum, while blood flow rate can be determined from the slope and y intercept of the curve approximating the power spectrum.

Abstract: An apparatus for measuring blood flow repeatedly segmentally scans a region of in vivo tissue with a coherent light beam. Each scanning segment comprises a scanning period during which the light beam is scanned and a rest period during which the light beam is not scanned. During the rest period, the light beam is directed at a measuring point of the in vivo tissue. Measurement data is obtained dependent on the intensity of scattered light from the measurement point. The measurement data is time series data of chronological changes in the intensity of scattered light caused by blood in the in vivo tissue. The blood flow rate is calculated from frequency-analysis of the time series data.

Abstract: An apparatus for measuring blood flow in which an optical system guides a coherent light beam to impinge on a stationary measurement spot of a measurement plane of an in vivo tissue. A light-receiving optical system focuses a light image of the measurement plane in the vicinity of an image point conjugate with the stationary measurement spot. The light-receiving optical system shares at least part of the optical components of the guiding optical system. Photodetectors are disposed at prescribed positions perpendicular to the optical axis of the light-receiving optical system, and in the vicinity of the image point, for measuring light scattered from the in vivo tissue to provide blood flow information. The blood flow information is related to blood flowing at a depth within the in vivo tissue. A visible image of the measurement plane is converted into a video image.

Abstract: A particle measurement apparatus is disclosed in which a laser beam is projected at a sample containing particles to be measured in a measurement zone and light scattered by particles in the sample is evaluated to thereby determine properties of particles in the sample. The apparatus includes a plurality of light receiving systems for receiving scattered light arranged at different angles relative to the axis of the laser beam. The amplitude of scattered light signals from the light receiving systems are compared with predetermined values. The arrangement is such that particles are counted by size only when the scattered light signals from the light receiving systems exceed a predetermined value, enabling false signals caused by noise and the like to be eliminated and assuring more accurate measurements.

Abstract: A method and apparatus for measuring the velocity of a fluid in which a double-exposure image of the speckle pattern or particle images of tracer particle in a fluid is irradiated with a collimated beam of coherent light, and is subjected to Fourier transformation to produce Young's fringes at its focal plane. A slit is rotated relatively with respect to the double-exposure image to produce changes in the amount of light transmitted by the slit and determine the direction of the fringes. To determine the spacing of the fringes, a variable-spacing grating filter is used which is complementary to the image of the fringes and has a transmission distribution function of sin.sup.2 or cos.sup.2. The thus obtained direction and spacing of the fringes are used to determine the velocity of the fluid.