Colour correcting image reproducing methods and apparatus

Claim 3

A method in accordance with claim 1, in which the signals representing the said color component densities constitute store addresses from which computed output values for those signals are obtained.

Claim 4

A method in accordance with claim 1, in which during setting of the parameter values output signals computed for the instantaneous parameter values are displayed for assessment.

Claim 5

A method in accordance with claim 1, in which the colour component signals are converted into digital form and the most significant digits of each signal are used as an input to the store, the remaining digits of each signal being applied to an interpolator receiving the store output.

Claim 6

Apparatus for use in the reproduction of a coloured image, including a photo-electric analysing scanner for deriving signals representing colour component densities of successively scanned elements of the original, an output scanner for treating successively scanned elements of an output surface in accordance with variations in an electric signal applied thereto, and signal-modifying means responsive to the signals from the analysing scanner to derive and to apply to the output scanner signals bearing a predetermined relationship to the input signals, the signal-modifying means including storage means for storing a matrix of output values, any of which can be extracted from the store in response to the corresponding signal from the analysing scanner, the apparatus further including, for entering the said matrix of output values into the store, a digital computer programmed to provide tone and colour correction of signals applied thereto, a parameter setting means for initially adjusting the values of parameters used by the computer, signal generating means for generating a matrix of input signals and for applying said input signals to said computer; and means for transferring tone and colour corrected output signals from said computer to said store.

Claim 7

Apparatus for use in the reproduction of a coloured image, including a photo-electric analysing scanner for deriving signals representing colour component densities of successively scanned elements of the original, an output scanner for treating successively scanned elements of an output surface in accordance with variations in an electric signal applied thereto, and signal-modifying means responsive to the signals from the analysing scanner to derive and to apply to the output scanner signals bearing a predetermined relationship to the input signals, the signal-modifying means including storage means for storing a matrix of output values, any of which can be extracted from the store in response to the corresponding signal from the analysing scanner, the apparatus further including, for entering the said matrix of output values into the store, a digital computer programmed to provide tone and colour correction of signals applied thereto, a parameter setting means for initially adjusting the values of parameters used by the computer, signal generating means for generating a matrix of input signals and for applying said input signals to said computer; and means for transferring tone and colour corrected output signals from said computer to said store.

Claim 8

Apparatus in accordance with claim 5, in which the output signals from said digital computer are stored in the store in locations having adDresses corresponding to said signals from said signal generator, whereby by addressing the store with a signal derived from said scanner, the corresponding tone and colour-corrected signal is obtained at the output of said store.

Claim 9

Apparatus in accordance with claim 5, including analogue-digital converters for converting the colour component signals into digital form, and in which the store is connected to receive the digital colour component signals and address signals, the apparatus including an interpolator including means for incrementing addresses applied to the store by one, means for multiplying the store outputs for different combinations of input values and incremented input values by multiplying factors derived from the least significant part of the colour component signals, and means for accumulating a number of products of the multiplying factors and the store outputs to obtain the output value having the said relationship to the input value.