Multispectral photography using multi-channel led cluster

The results presented of an experiment of multispectral imaging the using led clusters without the use of filters . The advantages and disadvantages of this method relative to conventional survey through the filter system. The sources of random and systematic errors demonstrated. Discusses the prospects of using this method of multispectral imagery in creating instrumentation for printing.Представлены результаты эксперимента по применению светодиодного кластера для мультиспектральной фотосъёмки без использования светофильтров. Рассмотрены преимущества и недостатки данного способа по отношению к традиционной съёмке через систему фильтров. Указаны источники возникновения случайной и систематической погрешностей. Обсуждаются перспективы использования данного способа мультиспектральной съёмки при создании контрольно-измерительной аппаратуры для полиграфии

LED Selection for Spectral (Multispectral) Imaging

Research was performed to design an LED-based spectral imaging system having channels, commonly referred to as a multispectral imaging system. The first part tackled the evaluation of a camera model in predicting the signals of a 10 LED LEDmotive Technologies Spectra Tunelab coupled with a Finger Lakes Instrumentation panchromatic camera. The camera model was shown to be valid and effective in predicting the camera signal taking into account the color transformation noise. The second part involved the computational selection of 10 LEDs in order to determine the optimum combination for a custom Spectra Tunelab. The computational selection used the spectral data provided by the manufacturer for their 37 available LEDs. The LEDs were grouped according to a specified wavelength range. The binning process helped in decreasing the computational cost and time; the possible combinations were reduced to 110,592 from the initial calculated value of 348,330,136 possible combinations. The combinations were further reduced to 1000 according to spectral reflectance Root-Mean-Square-Error (RMSE). The Euclidean and score ranking methods were then used to evaluate color transformation noise, spectral error and colorimetric accuracy. Goodness of Fit Coefficient and Throughput were calculated as well to further evaluate the combinations. A compromise among the values were reached to identify the best possible LED combination. The optimal combination has peak wavelengths at 390 nm, 450 nm, 475 nm, 505 nm, 540 nm, 550 nm, 590 nm, 620 nm, 660 nm, and 745 nm. All the LEDs were narrow band except the LED with its peak wavelength at 550 nm. This particular LED was similar to the human visual system’s luminous efficiency function. Its inclusion was important for colorimetric accuracy and small color transformation noise. When evaluating a large color-gamut target made using commonly used commercial pigments and several artist pigments, the following quality metrics were achieved: average ∆E00 of 0.12, total Noise, N of 3.35, a lightness noise (∆L) of 1.22, spectral reflectance RMSE of 6.4 x10-3, GFC of 0.97 and a total throughput of 646.85

Expanding Dimensionality in Cinema Color: Impacting Observer Metamerism through Multiprimary Display

Television and cinema display are both trending towards greater ranges and saturation of reproduced colors made possible by near-monochromatic RGB illumination technologies. Through current broadcast and digital cinema standards work, system designs employing laser light sources, narrow-band LED, quantum dots and others are being actively endorsed in promotion of Wide Color Gamut (WCG). Despite artistic benefits brought to creative content producers, spectrally selective excitations of naturally different human color response functions exacerbate variability of observer experience. An exaggerated variation in color-sensing is explicitly counter to the exhaustive controls and calibrations employed in modern motion picture pipelines. Further, singular standard observer summaries of human color vision such as found in the CIE’s 1931 and 1964 color matching functions and used extensively in motion picture color management are deficient in recognizing expected human vision variability. Many researchers have confirmed the magnitude of observer metamerism in color matching in both uniform colors and imagery but few have shown explicit color management with an aim of minimized difference in observer perception variability. This research shows that not only can observer metamerism influences be quantitatively predicted and confirmed psychophysically but that intentionally engineered multiprimary displays employing more than three primaries can offer increased color gamut with drastically improved consistency of experience. To this end, a seven-channel prototype display has been constructed based on observer metamerism models and color difference indices derived from the latest color vision demographic research. This display has been further proven in forced-choice paired comparison tests to deliver superior color matching to reference stimuli versus both contemporary standard RGB cinema projection and recently ratified standard laser projection across a large population of color-normal observers