Abstract: An apparatus and a method are provided for selectively eliminating weeds in agriculture operations. To provide selective elimination, at least two light (radiation) emitters, powered by an internal power source, are modulated to switch on and off at very high speeds. Each emitter emits radiation of a different emitter wavelength. The on/off modulation of one emitter is phase shifted by approximately 90.degree. with respect to the modulation of the other emitter. The pair of emitters are focused on a particular spot on the ground. The light beams, provided by the emitters, are reflected off a plant or the soil and are intercepted by a photodetector. Because plants have a characteristic spectral reflectance in regions of the electromagnetic spectrum which can be discriminated from the spectral reflectance of the background earth, the relative amplitudes of the reflected radiation at the two emitter wavelengths varies depending on whether the radiation is reflected off a plant or the soil.

Abstract: An optical density detector which comprises a first light source for emitting a first light which belongs to a wavelength region in which the first light is hardly absorbed by a specific material contained in a sample, a second light source for emitting a second light which belongs to a wavelength region in which the second light is absorbed, substantially as compared with the first light, by the specific material, wherein a peak-wavelength of the second light is shifted by change of a temperature and change of an absorption of the specific material caused by the peak-wavelength shift is characteristic of a linear equation with a gentle grade, light receiving device for measuring a quantity of the first and the second lights which are transmitted through the sample, an arithmetic unit for calculating difference of absorbance between the first light and the second light of which both change depending on the density of the specific material, a temperature measuring device for measuring the temperature of the fi

Abstract: An apparatus for rapid colorimetry on different samples which has a transmitter for irradiating or through-radiating the particular sample and a receiver for receiving the radiation reflected or transmitted by the sample, as well as a filter arrangement. Also included is a computer for evaluating the signals from the receiver. The transmitter is formed by several semiconductor radiation sources, which irradiate in different spectral ranges and whose optical radiation is combined by means of a filter unit and is deflected onto the sample by a lens arrangement. A control unit controls the semiconductor radiation sources in successive pulsewise intervals. The control unit also supplies a signal permitting an association of the receiver signals to the radiation emitted in the different spectral ranges.

Abstract: A device for measuring transmittance of light comprises a light source, photodetector and signal processor. The concentration of a substance in a fluid sample can be accurately determined by coating the light source with a reagent that is chemically reactive with the substance and measuring light transmitted from the coating before and after the substance is applied to the coating. The coating can contain a solid support matrix, such as a translucent nonwoven paper web of the type used in reagent test strips and similar indicator devices. The invention is useful for making clinical analyses on body fluids.

Abstract: A device for detecting differences in color of a material to be inspected, which device comprises a first light source emitting light of a first color and a second light source emitting light of a second color, an optical system adapted to project portions of the light emitted both by the first and the second light source onto first and second spaced apart measuring regions respectively, each measuring region being associated with means for measuring the amount of light reflected by the material. The device further comprises electronic switching means for alternately energizing the first and the second light source, means for transporting the material, means for controlling the intensity of the second light source in dependence upon the measured amount of reflected first light source light, and means for determining a difference in color from the measured amounts of reflection.

Abstract: A color sensor includes a plurality of light emitting sources of different colors each of which is driven in a time divisional manner to emit the different colors sequentially, a light receiving element for receiving the light from an object illuminated by the respective color lights from the light emitting sources and a circuit arrangement for producing output signals representing the color of the object.

Abstract: In an apparatus for reading a color image on an original wherein the color image is illuminated and scanned by light from a plurality of light sources each having different spectrum to discriminate color of the color image on the basis of the reflected light from the original, these plurality of light sources are driven by a driving signal which is produced in synchronism with original read scanning.

Abstract: A light processor applied to the modulation of colored light, formed of a color modulated light source, includes a longitudinal modular box forming a frame and a support for the components of the source, the box being formed with windows for the passage of light beams and connection openings for control circuits, as well as devices for fixing the components of the source, and devices for assembly means with similar boxes, for providing, by superposition and/or juxtaposition, assemblies of boxes adapted to the various applications envisaged. The light source has a reflector and is mounted inside the box on a base thereof. A plurality of dichroic inclined mirrors are mounted one after the other on the base inside the box along the path of the light beam emitted by the light source, such that each dichroic mirror reflects a portion of the light spectrum emitted by the source, and transmits the remaining portion of the beam to the subsequent mirror.

Abstract: The invention relates to a spectrophotometer operating at discrete wavelengths comprising diodes to emit variable, substantially monochromatic radiation for irradiating a sample (10) to be tested, a radiation detector (12) sensing the intensity of the radiation reflected or transmitted by the sample (10) and a signal processing unit connected to the radiation detector (12). The diodes comprise radiation sources (2) emitting substantially monochromatic radiation of different wavelengths, a holder (1) supporting the radiation sources (2) and an optical arrangement (5,6) for transmitting the radiation emitted by the radiation sources (2) successively towards the sample (10). The optical arrangement may comprise at least one mirror (5) supported rotatably with respect to the holder (1).

Abstract: Color is synthesized by dispersing a beam of light to form a spectrum, effectively blocking a portion of the spectrum with a mask, and recombining the light energies of the unblocked portion(s) of the spectrum to synthesize the color.

Abstract: An apparatus visually duplicates the hue, tone, intensity and shape of a selected gemstone by combining predetermined intensities of red, green and blue light sources within a color mixing box. A single variable intensity light source and a monochromatic filter provide each of the three colors. Colored light from each light source is passed through a portion of a multi-segment diffusion lens prior to entering the color mixing box. The three separate colors are combined within the color mixing box and reflected from an image wheel which includes various geometric patterns. Light propagated from the color mixing box passes through a silhouette wheel to a crystal wheel which provides an appropriate gemstone shape. The light then passes through an image magnifier which controls the apparent size of the gemstone. Controls are provided to modify the shape, color and intensity of the duplicated gem displayed by the apparatus.

Abstract: An apparatus for generating patterned images which are variable in color contrast and spatial frequency while retaining a substantially constant, uniform level of photometric luminance. Two broad spectrum beams of luminous energy are individually projected through two orthogonally oriented polarizers and interleaved upon being split. The intensity in one beam is homogeneous while the other contains a spatially periodic pattern. The two beams created by splitting and interleaving are selectively color filtered and combined after one is translated sufficiently to reverse its phase relative to the other. A rotating polarizer in the path of the output combined beam alters the pattern color composition between one extreme where the spatially reversing colors are defined by the color filters and the opposite extreme in which the pattern disappears into a uniform composition of the two colors.

Abstract: The device is housed in an enclosure impervious to light of a selected frequency spectrum. The housing contains a light source of the same frequency spectrum and a pair of translatable filter holders. Each of the filter holders contain different chromic absorption filters positioned in a side-by-side relationship in the direction of translation. The chromic absorption filters are arranged with a color filter on one end of the holder and its color filter complement on the other end. A second embodiment contains an achromic or neutral filter positioned between the complementary chromic filters. The filters of each holder have vertical alignment when one is superposed over the other. A mask is provided between the filter holding means for allowing light from the source to pass through an area equal to approximately the width of one chromic filter. Thus, this light is then directed toward a color positive for correct light balancing.