In a calibration method, high-accuracy reference values obtained using a high-accuracy optical sensor are received, low-accuracy reference values are determined from reference colors captured from a display using a low-accuracy optical sensor having a lower accuracy than the high-accuracy optical sensor, color measurement values are determined from one or more colors captured from the display using the low-accuracy optical sensor, and the color measurements values are adjusted based on one or more color conversion equations to obtain adjusted color measurement values. The one or more color conversion equations are based on the high-accuracy measurement values and the low-accuracy measurement values. The high-accuracy reference values are reused for calibrations of one or more other low-accuracy optical sensors.

Methods are provided for generating a barcode with embedded colour palette for colour correction of a captured image in digital format. These methods comprise: generating an initial barcode according to a barcode standard and formed by light colour and dark colour encoding units jointly encoding a reference to storage location; splitting a predefined set of reference colours into reference dark and reference light colours depending on contrast threshold; modifying the initial barcode by replacing dark colour encoding units by reference dark colours and light colour encoding units by reference light colours; and updating the storage location with data representing the reference colours included in the modified barcode and positions of said reference colours in the modified barcode. Methods are provided for colour correction based on a barcode determined by said methods. Computer programs and systems are provided which are suitable for performing said barcode generation methods and colour correction methods.

There is provided a calibration apparatus including one or a plurality of first processors programmed to: obtain spectrum images from a spectral camera that images light from alight source portion; obtain a spectral reference value from a measurement result of a calibration reference device that measures the light; extract a gradation value at a correction point that is a pixel which generates a correction matrix among the spectrum images as a measurement value; divide the measurement value at the correction point and the spectral reference value by a luminance value of the light emitted from the light source portion to obtain a normalized measurement value and a normalized reference value; and calculate the correction matrix based on the normalized measurement value and the normalized reference value.

An image forming apparatus that prints an adjustment pattern on a sheet includes a generator and an image former. The adjustment pattern is for correcting a color value obtained by reading a second patch region on the sheet with a second reader based on a color value obtained by reading a first patch region on the sheet with a first reader. The generator generates image data of the adjustment pattern, and the image former performs printing based on the image data. The adjustment pattern includes a first patch printed in the first patch region and a second patch printed in a region other than the first patch region in the second patch region. The second patch includes a common color patch in a same color as a color of the first patch, and a size of the first patch is larger than a size of the second patch.

In one embodiment, a diagnostic system for biological samples is disclosed. The diagnostic system includes a diagnostic instrument, and a portable electronic device. The diagnostic instrument has a reference color bar and a plurality of chemical test pads to receive a biological sample. The portable electronic device includes a digital camera to capture a digital image of the diagnostic instrument in uncontrolled lightning environments, a sensor to capture illuminance of a surface of the diagnostic instrument, a processor coupled to the digital camera and sensor to receive the digital image and the illuminance, and a storage device coupled to the processor. The storage device stores instructions for execution by the processor to process the digital image and the illuminance, to normalize colors of the plurality of chemical test pads and determine diagnostic test results in response to quantification of color changes in the chemical test pads.

A method for generating a calibration parameter for light sources includes activating at least one LED of a plurality of multicolor LEDs of a light source and measuring a color of the at least one LED in a first color space. The method also includes scaling the color of the at least one LED relative to the plurality of multicolor LEDs, obtaining a plurality of scaled color measurements, and calculating a calibration matrix based on the plurality of scaled color measurements.

In accordance with one or more implementations of the apparatus, system and methods described, a sample measurement device is provided that is configured to measure the color of a sample. The sample measurement device includes at least one light source configured to illuminate the sample; at least one light sensor configured to output a signal in response to light emitted by light source and reflected off the sample being received by at least a portion of the light sensor; and a processor configured to receive the signal and calculate a color value for the sample, the processor configured to calculate the color value by at least adjusting the signal using a calibration factor.

A hyperspectral imaging spectrophotometer and system, with calibration, data collection, and image processing methods designed to match human visual perception and color matching of complex colored objects.

A method has been developed to monitor the aging of an illuminator (such as a lamp) and the interior sphere wall in a sphere-based color measurement instrument. This monitoring process or method is configurable to independently monitor the aging of the illuminator as well as the aging of the interior surface of a color measurement device using standard calibration measurements already present in the color measurement device.

A system and method is provided for color matching two or more electronic displays of a display system. The method includes: obtaining first and second spectral response readings for first and second electronic displays from spectral response device(s); determining first and second spectral response curves based on the first and second spectral response readings; determining first and second spectral power distributions based on the first and second spectral response readings; determining a first device-to-independent color mapping based on the first spectral response curve and the first spectral power distribution; determining a second device-to-independent color mapping based on the second spectral response curve and the second spectral power distribution; and configuring a display system having the first electronic display and the second electronic display to match colors being displayed based on using the first device-to-independent color mapping and the second device-to-independent color mapping.