Patent ID: 6647140
Filing Date: 2003-11-11
Classification: H04N

Abstract:
An apparatus that inverts the spectrum of image data, comprising:an image data input device that inputs image data of an input image in an input color space; a medium identification device that identifies an input image medium from which the input image data was obtained; and a spectrum inversion device that selects one of a plurality of spectrum inversion methods to convert the input image data into output image data in a spectral space based on the identification of the input image medium, the spectrum inversion device including a neural network, wherein the neural network includes input nodes, hidden nodes and output nodes, connections between the input nodes and the hidden nodes are represented by a 3Ã—10 matrix, connections between the hidden nodes and the output nodes are represented by a 10Ã—36 matrix, entries of the 3Ã—10 matrix and the 10Ã—36 matrix are determined to minimize a merit function, the merit function is a weighted root-mean-square (RMS) spectral error defined as: &Sum;&Sum;i=136&it;â€ƒ&it;w&af;(Î»&it;â€ƒ&it;i)*(Rdesired&af;(Î»&it;â€ƒ&it;i)-Routput&af;(Î»&it;â€ƒ&it;i))2â€ƒwhere &lgr;i, i=1, 2, . . . , 36 are sampling wavelengths, Rdesired (&lgr;i) and Routput (&lgr;i) are the spectral reflectance of desired output and actual output, and w(&lgr;i) is a weight factor.