Apparatus for reproducing colored images

Claim 2

In colour picture reproducing apparatus including: a colour picture analysing scanner for scanning a colour picture, element by element, and analysing its colour components to provide a set of electric signals, each such scanner signal representing by its value at any instant the density of a different colour component of the scanned element of the colour picture; means including a colour component channel for each of the said colour component scanner signals for obtaining therefrom colour component printer signals; and means responsive to the colour-component printer signals for exposing photosensitive sheets by means of which colour-component printers can be made; the means for deriving the colour-component printer signals including a correcting circuit for correcting the value of at least one colour-component signal in dependence on the value of another colour-component signal; the improvement consisting in that the means for deriving the colour-component printer signals further includes: a hue-recognitiion circuit including means for deriving colourcomponent signals from the said colour component channels and for adding a voltage to each of at least two of the derived signals, the voltage added to each derived signal being such that the resultant signals from the said colour channels, after addition of the said voltages, are of substantially equal value when the derived signals in combination, prior to the additioN of the said voltages, represent the hue to be recognised; and a hue-modifying circuit responsive to substantial equality of the said resultant signals to modify the colour printer signals obtained from the said colour channels and thereby to modify the reproduction of the said hue of the scanned colour picture.

Claim 3

Colour picture reproducing apparatus as defined in claim 1, in which the means responsive to substantial equality of the resultant signals includes a maximum signal selector circuit and a minimum selector circuit for selecting the largest and smallest of the colour-representing signals, respectively, after the said voltage addition, and a comparator for comparing the largest and smallest signals.

Claim 4

Colour picture reproducing apparatus as defined in claim 1, in which the means for adding a voltage to a colour component signal includes, for each colour component signal to which a voltage is to be added, a voltage selector circuit, whereby different combinations of voltages may be selected, each different combination representing a different hue to be recognised.

Claim 5

Colour picture reproducing apparatus as defined in claim 3, in which the means responsive to substantial equality of the resultant signals includes a maximum signal-selector circuit and a minimum signal-selector circuit for selecting the largest and smallest of the colour-representing signals, respectively, after the said voltage addition, and a comparator for comparing the largest and smallest signals, the apparatus additionally including a further voltage-selector circuit, adjusted in step with the voltage-selector circuits for the said colour-component signals to select one of a number of preset biasing voltages and to add the selected biasing voltage to the output of one of said signal-selector circuits for application to said comparator.

Claim 6

In colour picture reproducing apparatus including: a colour picture analysing scanner for scanning a colour picture, element by element, and analysing its colour components to provide a set of electric signals, each such scanner signal representing by its value at any instant the density of a different colour component of the scanned element of the colour picture; means including a colour component channel for each of the said colour component scanner signals for obtaining therefrom colour component printer signals; and means responsive to the colour-component printer signals for exposing photosensitive sheets by means of which colour-component printers can be made; the means for deriving the colour-component printer signals including a correcting circuit for correcting the value of at least one colour-component signal in dependence on the value of another colour-component signal; the improvement consisting in that the means for deriving the colour-component printer signals further includes: a hue-recognition circuit including means for detecting the existence of a set of differences, between the values of different ones of the set of colour-component signals, which substantially correspond to predetermined colour-component signal differencs defining a predetermined hue, said hue-recognition circuit including adjustable hue-selecting means variable over a range of values of each of the colour component signals to select any hue defined by colour component values within the said ranges; and a hue-modifying circuit responsive to the detection of the said set of actual differences corresponding to the predetermined differences and operative to apply a modifying signal to one or more colour-component channels to modify the reproduction of the said hue of the original picture, each modifying signal having a value which is continuously variable over a range, having a maximum value for exact correspondence of the said actual and predetermined differences, and decreasing with both increase and decrease in any of the said actual differences.

Claim 7

In colour picture reproducing apparatus including: a colour picture analysing scanner for scanning a colour picture, element by element, and analysing its colour components to provide a set of electric signals, each such scanner signal representing by its value at any instant the density of a different colour component of the scanned element of the colour picture; means including a colour component channel for each of the said colour component scanner signals for obtaining therefrom colour component printer signals; and means responsive to the colour-component printer signals for exposing photosensitive sheets by means of which colour-component printers can be made; the means for deriving the colour-component printer signals including a correcting circuit for correcting the value of at least one colour-component signal in dependence on the value of another colour-component signal; the improvement consisting in that the means for deriving the colour-component printer signals further includes: a hue-recognition circuit including means for detecting the existence of a set of differences, between the values of different ones of the set of colour-component signals, which substantially correspond to predetermined colour-component signal differencs defining a predetermined hue, said hue-recognition circuit including adjustable hue-selecting means variable over a range of values of each of the colour component signals to select any hue defined by colour component values within the said ranges; and a hue-modifying circuit responsive to the detection of the said set of actual differences corresponding to the predetermined differences and operative to apply a modifying signal to one or more colour-component channels to modify the reproduction of the said hue of the original picture, each modifying signal having a value which is continuously variable over a range, having a maximum value for exact correspondence of the said actual and predetermined differences, and decreasing with both increase and decrease in any of the said actual differences.