This paper describes a new type of multichannel color sensor with the special property of having all channels per pixel at the same spatial location one on top of the other. This arrangement is accomplished by stacking three amorphous thin film detectors on a glass substrate. It has the advantage that the color noire effect is avoided which produces large color errors when objects of high spatial frequency are captured with a multi-channel sensor array. The new technique enables the design of a three-channel sensor as well as a six-channel sensor. In the latter case, color is captured in two 'shots' by changing the bias voltages. The colorimetric characterization of the sensors is presented, including multiple polynomial regression both for tristimulus and spectral reconstruction, and the smoothing inverse for spectral reconstruction. The result obtained with different types of regression polynomials, different sensors, and different characterization methods are compared. The results show that the three-channel color moire free sensors are able to produce good accuracy, while the six-channels' performance is striking.
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