Abstract: A visible light communications transmitter combines a modulated carrier signal with a pulse from a pulse generator. The carrier signal is modulated according to data read from a buffer during the pulse.

Abstract: A color printing system includes a color monitor and printer having different color gamuts. A color chart is printed out by the printer. A light source outputs light to the color printer and a color sensor detects the light reflected from the color chart printout. The sensor outputs sensor color values representing the light received from the color chart printout. A print-preview matrix is calculated from the monitor color chart values and the sensor color values. An image is input to and displayed by the monitor and is converted into a print-preview image using the print-preview matrix. The monitor displays the monitor image and the print-preview image before printing the image.

Abstract: Method and apparatus for duplicating a target color and changing a color of an object to match the target color. A first color sensor measures the target color. A color projection mechanism selectively changes the color of the object. A color matching mechanism is coupled to the first color sensor for receiving the target color. Based on the target color, the color matching mechanism controls the color projection mechanism to change the color of the object to match the target color.

Abstract: Systems and methods for illumination and color management in a system having a plurality of color sources and a plurality of color sensors, wherein there are more color sources than color sensors are described herein. An embodiment of the method includes emitting a plurality of different colors of light from at least two of the color sources, wherein the plurality of colors consist of different intensities of light emitted by the plurality of color sources. Colors of light emitted by the at least two color sources are detected using at least one of the color sensors. The color rendering index for each of the plurality of colors emitted is determined. A color of light to be emitted by the light sources is selected. The intensities of light to be emitted by the color sources is selected, based at least in part on the color rendering index, to achieve the selected color of light.

Abstract: An ambient light sensor (ALS) system is described. The ALS system includes a polychromatic color sensor, an analog-to-digital converter (ADC), and a digital processor. The polychromatic color sensor generates a plurality of analog signals from a corresponding plurality of color channels based on a detected ambient light signal. The ADC is coupled to the polychromatic color sensor. The ADC converts the plurality of analog signals to a plurality of digital signals. The digital processor is coupled to the ADC. The digital processor generates a processed light signal. The processed light signal describes a characteristic of the detected ambient light signal. Embodiments of the ALS system provide a more comprehensive characterization of the ambient light, and facilitate control of a device based on the characterization of the ambient light.

Abstract: An ambient light sensor (ALS) system is described. The ALS system includes a polychromatic color sensor, an analog-to-digital converter (ADC), and a digital processor. The polychromatic color sensor generates a plurality of analog signals from a corresponding plurality of color channels based on a detected ambient light signal. The ADC is coupled to the polychromatic color sensor. The ADC converts the plurality of analog signals to a plurality of digital signals. The digital processor is coupled to the ADC. The digital processor generates a processed light signal. The processed light signal describes a characteristic of the detected ambient light signal. Embodiments of the ALS system provide a more comprehensive characterization of the ambient light, and facilitate control of a device based on the characterization of the ambient light.

Abstract: A meter for measuring the turbidity of a fluid includes a light source for directing a light beam through a fluid under test towards a reflective surface and a sensor for detecting light reflected from the reflective surface and passing back through the fluid under test. The meter outputs a signal indicative of the turbidity of the fluid under test.

Abstract: A meter for measuring the turbidity of a fluid includes a light source for directing a light beam through a fluid under test towards a reflective surface and a sensor for detecting light reflected from the reflective surface and passing back through the fluid under test. The meter outputs a signal indicative of the turbidity of the fluid under test.

Abstract: A visible light communications transmitter combines a modulated carrier signal with a pulse from a pulse generator. The carrier signal is modulated according to data read from a buffer during the pulse.

Abstract: A technique for measuring the color of ambient light involves a color sensor with color-specific interference filters and a diffuse reflecting surface that is configured to ensure that the ambient light is incident on the color-specific interference filters at the angle that produces optimal filtering. The diffuse reflecting surface causes reflected light to be spread evenly in the same direction relative to the diffuse reflecting surface regardless of the angle of incidence of the ambient light. The diffuse reflecting surface is oriented with respect to the color sensor to reflect the ambient light at the optimal filtering angle relative to the interference filters. Because of the diffuse reflecting surface, the ambient light is reflected to the interference filters at the optimal angle of incidence regardless of the angle at which the ambient light impacts the diffuse reflecting surface.

Abstract: A technique for sensing color involves detecting a portion of incident light that is not filtered by a color filter in addition to portions of the incident light that are filtered by color filters. The output related to the unfiltered light is used along with the outputs related to the filtered light to correct for voltage offsets that affect the amplification of the outputs. In an application, the output related to the unfiltered light is subtracted from the outputs related to the filtered light in a calculation of a linear transformation matrix.

Abstract: A counterfeit ink detector comprises a color printer calibrated by determining authentic ink color values for several authentic inks used by the color printer. A multi-color pattern is printed using multi-colored inks of a print cartridge. A light source outputs light to the color pattern and a color sensor detects light from the light source reflected from the color pattern. A processor processes the detected light to calculate pattern color values for color components of the color pattern, and compares the pattern color values to the authentic ink color values. A counterfeit ink signal is output by the processor if the difference between the pattern color values and the authentic ink color values is greater than a threshold value indicating counterfeit ink.

Abstract: A color printing system includes a color monitor and printer having different color gamuts. A color chart is printed out by the printer. A light source outputs light to the color printer and a color sensor detects the light reflected from the color chart printout. The sensor outputs sensor color values representing the light received from the color chart printout. A print-preview matrix is calculated from the monitor color chart values and the sensor color values. An image is input to and displayed by the monitor and is converted into a print-preview image using the print-preview matrix. The monitor displays the monitor image and the print-preview image before printing the image.

Abstract: In one embodiment, color sensors allow multiple data transfer channels to occur between a light source and a light detector. Light of differing wavelengths can be detected simultaneously and the modulated data on each wavelength can be independently and simultaneously processed. If desired, data from a selected wavelength can be delivered to an end-user. In another embodiment, different colors can be used for different directions of communication thereby allowing for simultaneous bi-directional communication.

Abstract: Scanner with light source calibration mechanism. The scanner includes a light source that generates a white light utilized to scan an image. The light source calibration mechanism includes a calibration color sensor that generates a calibration color sensor output. The light source calibration mechanism receives a predetermined color profile that can be, for example, the amount of red, green light, and blue light expected from the light source utilized by the scanner for scanning. The color calibration mechanism calibrates the light source of the scanner based on the output of the calibration color sensor and the predetermined color profile.

Abstract: A technique for sensing color involves detecting a portion of incident light that is not filtered by a color filter in addition to portions of the incident light that are filtered by color filters. The output related to the unfiltered light is used along with the outputs related to the filtered light to correct for voltage offsets that affect the amplification of the outputs. In an application, the output related to the unfiltered light is subtracted from the outputs related to the filtered light in a calculation of a linear transformation matrix.

Abstract: Method and apparatus for duplicating a target color and changing a color of an object to match the target color. A first color sensor measures the target color. A color projection mechanism selectively changes the color of the object. A color matching mechanism is coupled to the first color sensor for receiving the target color. Based on the target color, the color matching mechanism controls the color projection mechanism to change the color of the object to match the target color.

Abstract: Method and apparatus for detecting the presence of an analyte (e.g., gas/radiation) that utilizes color change detection mechanisms. The apparatus has an indicator that changes color in the presence of the analyte. For example, in the absence of the analyte, the indicator reflects a first color. In the presence of the analyte, the indicator reflects a second color. The apparatus includes a color sensor that receives light reflected from the indicator and based thereon generates one or more signals that represent the reflected light. The apparatus also includes a color change detection mechanism that is coupled to the color sensor and that receives the signal generated by the color sensor and based on the signal determines whether the indicator has changed to the second color. Once it is determined that the indicator has changed to the second color, an alarm can be generated or remedial measures can be initiated.