Noniterative algorithm for improving the accuracy of a multicolor-light-emitting-diode-based colorimeter

Abstract

We present a noniterative algorithm to reliably reconstruct the spectral reflectance from discrete reflectance values measured by using multicolor light emitting diodes (LEDs) as probing light sources. The proposed algorithm estimates the spectral reflectance by a linear combination of product functions of the detector's responsivity function and the LEDs' line-shape functions. After introducing suitable correction, the resulting spectral reflectance was found to be free from the spectral-broadening effect due to the finite bandwidth of LED. We analyzed the data for a real sample and found that spectral reflectance with enhanced resolution gives a more accurate prediction in the color measurement.

Determining the spectral responsivity from relative measurements by using multicolor light-emitting diodes as probing light sources

“…1, which was previuosly used for measuring the spectral reflectance [15,16]. Since the photodetector is usually used in the configuration of normal incidence.…”

“…Another correction methods modeling the spectrum by a piecewisely polynomial function are only applicable for spectral data with slowly varying behavior [9,13,14]. Recently, two useful algorithms had been developed to remove the spectral broadening effect in the spectral reflectance measured by using multicolor LEDs as probing light sources [15,16]. These two algorithms can be applied to arbitrary responsivity functions.…”

“…[16] to the reconstruction of the spectral responsivity from multiple data measured by using multicolor LEDs as probing light sources and further generalized the algorithm to the case with a nonideal reference. In addition, we present a relative measurement…”

“…(14) had been generalized from that we used for correcting the spectral reflectance [16], where an ideally white sample with constant reflectance was used as the reference surface. For an ideally white reflector as a reference surface in the spectral reflectance measurement, we can take advantage of  :peak wavelength of the i-th LED) in the reconstruction algorithm.…”