Method and circuit arrangement for contrast intensification

Claim 3

The method of claim 1, and further comprising the step of: inverting the auxiliary signal prior to the step (f) of adding the first differential signal and the auxiliary signal.

Claim 4

The method of claim 1, wherein the step (a) of opto-electronically scanning is further defined as: (a1) illuminating the master point-wise and line-wise to produce an image light beam; (a2) splitting the image light beam into three portions; (a3) passing the three beam portions through respective diaphragms having respective apertures each of a different size defining the respective image point and first and second outer field areas; and (a4) applying each beam portion passed through a diaphragm to an opto-electronic transducer to generate the respective image and first and second outer field signals.

Claim 5

The method of claim 1, wherein the steps (b), (c) and (d) of forming first, second and third differential signals are respectively further defined as: (b1) applying the image signal and the first outer field signal to a first differential amplifier; (c1) applying the image signal and the second outer field signal to a second differential amplifier; and (d1) applying the first and second outer field signals to a third differential amplifier.

Claim 6

The method of claim 4, wherein the steps (b), (c) and (d) are further defined by the respective steps of: (b2),(c2) and (d2) adjusting the amplification factor of the respective differential amplifiers to weight the differential signals.

Claim 7

The method of claim 1, wherein the step (e) of combining the differential signals is further defined as: (e1) combining all three differential signals to obtain symmetrical contrast intensification.

Claim 8

The method of claim 1, wherein the step (e) of combining the differential signals is further defined as: (e1) logically combining all three differential signals.

Claim 9

The method of claim 1, wherein the step (e) of combining the differential signals is further defined as: multiplying together all three differential signals.

Claim 10

The method of claim 1, wherein the image signal is modified in accordance with a gradation, and further comprising the steps: (h) varying the gradation as a function of the second outer field signal.

Claim 11

The method of claim 1, wherein the step (a) of opto-electronically scanning is further defined as comprising the step of: (i) calculating the first and second outer field signals from image points lying in respective scan areas.

Claim 12

An arrangement for contrast intensification in the reproduction of masters, comprising: a scanner operable to scan a master point-wise and line-wise and including a first scanner circuit for producing an image signal in response to the brightness of an image point, a second scanner circuit for producing first outer field signal in response to the mean brightness of a first scanning field larger than that of the image point, and a third scanner circuit for producing a second outer field signal in response to the mean brightness of a second scanning field larger than the first scanning field; differential signal means connected to said scanner and operable to produce a first differential signal in response to said image signal and first outer field signal, a second differential signal in response to said image signal and second outer field signal, and a third differential signal in response to said first and second outer field signals; selection means connected to said differential signal means and operable to select differential signals for combining; combining means connected to said selection means for combining the selected differential signals into an auxiliary signal; and an arithmetic stage connected to said combining means and to said differential means for algebraically combining said auxiliary and first differential signals to form a correction signal.

Claim 13

An arrangement for contrast intensification in the reproduction of masters, comprising: a scanner operable to scan a master point-wise and line-wise and including a first scanner circuit for producing an image signal in response to the brightness of an image point, a second scanner circuit for producing first outer field signal in response to the mean brightness of a first scanning field larger than that of the image point, and a third scanner circuit for producing a second outer field signal in response to the mean brightness of a second scanning field larger than the first scanning field; differential signal means connected to said scanner and operable to produce a first differential signal in response to said image signal and first outer field signal, a second differential signal in response to said image signal and second outer field signal, and a third differential signal in response to said first and second outer field signals; selection means connected to said differential signal means and operable to select differential signals for combining; combining means connected to said selection means for combining the selected differential signals into an auxiliary signal; and an arithmetic stage connected to said combining means and to said differential means for algebraically combining said auxiliary and first differential signals to form a correction signal.

Claim 14

The arrangement of claim 11, and further comprising: a superposition stage connected to said arithmetic stage and said first scanner circuit for superimposing said image signal and said correction signal.

Claim 15

The arrangement of claim 11, wherein: said combining means comprises a multiplier.

Claim 16

The arrangement of claim 11, wherein: said second scanner circuit comprises a first diaphragm including a first aperture which determines a first outer field scanning area, and a first opto-electronic transducer light-coupled to said first aperture for producing the first outer field signal; and said third scanner circuit comprises a second diaphragm including a second aperture which determines a second outer field scanning area, and a second opto-electronic transducer light-coupled to said second aperture for producing the second outer field signal.

Claim 17

The arrangement of claim 11, wherein: said differential signal means comprises first, second and third differential amplifiers, said first differential amplifier connected to receive the image point and first outer field signals, said second differential amplifier connected to receive said image point and second outer field signals, and said third differential amplifier connected to receive said first and second outer field signals.

Claim 18

The arrangement of claim 11, and further comprising: an inverter connected between said combining means and said arithmetic stage.

Claim 19

The arrangement of claim 11, wherein: said arithmetic stage comprises an adder.

Claim 20

The arrangement of claim 11, wherein: said arithmetic stage comprises a subtractor.

Claim 21

An arrangement for reproducing masters with a contrast intensification, comprising: a first rotatable drum for carrying a master to be reproduced; a second rotatable drum for carrying a recording medium; a recording element operable to scan and record on the recording medium; scanning means for scanning the master point-wise and line-wise, including light means for causing a light beam to be transmitted from the master, dividing means for dividing the light beam into first, second and third portions, first, second and third diaphragms each disposed to respectively receive the first, second and third light beam portions and each including an aperture therethrough for passing a respective light component of the respective beam portion, said first diaphragm aperture defining an image point, said second diaphragm defining a first outer field about and larger than the image point, and said third diaphragm defining a second outer field about the image point and larger than the first outer field, and first, second and third opto-electronic transducers each disposed to receive a respective light component from a respective diaphragm and operable in response thereto to produce respective image point, first outer field and second outer field signals; first, second and third differential amplifiers, said first differential amplifier connected to receive and form a first differential signal from said image point signal and first outer field signal, said second differential amplifier connected to receive and form a second differential signal from said image point signal and said second outer field signal, and said third differential amplifier connected to receive and form a third differential signal from said first and second outer field signals; a multiplier for multiplying together selected differential signals; selection means connected between said first, second and third differential amplifiers and said multiplier for selecting differential signals for multiplication; arithmetic means connected to said first differential amplifier and to said multiplier for algebraically adding said first differential signal and the product of multiplication to obtain an auxiliary signal; superposition means connected to said first opto-electronic transducer and to said arithmetic means to superimpose said auxiliary and image point signals to form a correction signal; and drive means connected between said superposition means and said recording element to operate said recording element to reproduce the master on the recording medium.

Claim 22

An arrangement for reproducing masters with a contrast intensification, comprising: a first rotatable drum for carrying a master to be reproduced; a second rotatable drum for carrying a recording medium; a recording element operable to scan and record on the recording medium; scanning means for scanning the master point-wise and line-wise, including light means for causing a light beam to be transmitted from the master, dividing means for dividing the light beam into first, second and third portions, first, second and third diaphragms each disposed to respectively receive the first, second and third light beam portions and each including an aperture therethrough for passing a respective light component of the respective beam portion, said first diaphragm aperture defining an image point, said second diaphragm defining a first outer field about and larger than the image point, and said third diaphragm defining a second outer field about the image point and larger than the first outer field, and first, second and third opto-electronic transducers each disposed to receive a respective light component from a respective diaphragm and operable in response thereto to produce respective image point, first outer field and second outer field signals; first, second and third differential amplifiers, said first differential amplifier connected to receive and form a first differential signal from said image point signal and first outer field signal, said second differential amplifier connected to receive and form a second differential signal from said image point signal and said second outer field signal, and said third differential amplifier connected to receive and form a third differential signal from said first and second outer field signals; a multiplier for multiplying together selected differential signals; selection means connected between said first, second and third differential amplifiers and said multiplier for selecting differential signals for multiplication; arithmetic means connected to said first differential amplifier and to said multiplier for algebraically adding said first differential signal and the product of multiplication to obtain an auxiliary signal; superposition means connected to said first opto-electronic transducer and to said arithmetic means to superimpose said auxiliary and image point signals to form a correction signal; and drive means connected between said superposition means and said recording element to operate said recording element to reproduce the master on the recording medium.