Method and device for sequentially imaging an original

Claim 2

Device for optically scanning a sequence of regions within an original and for generating an electrical signal dependent both upon the light intensity and upon its distribution within the region currently scanned, where a sequence of such signals is used for generating a discrete image of the original, characterized by an optional scanning head arranged so as to sequentially scan all regions, means between said scanning head and said photo-sensors for variably restricting the light impinging on said sensors, imaging each region on at least two photo-sensors, the outputs of which are connected to an inverting and to a noninverting input, respectively, of an adding circuit which generates the difference of the primary signals.

Claim 3

Device according to claim 1, characterized by a semi-reflecting mirror placed in the light beam of the scanning head, and by at least two photo-sensors, of which one is placed in each of the two partial light beams downstream of the semi-reflecting mirror.

Claim 4

Device according to claim 1, characterized by a plurality of mutually concentric sensors.

Claim 5

Device according to claim 1, wherein said means is an optical filter with locally varying density.

Claim 6

Device according to claim 4, characterized in that the density of the filter has a rotational symmetry.

Claim 7

Method for optically scanning a sequence of regions throughout an original for generating an electrical signal dependent both upon the light intensity and its distribution within the region being scanned in order to produce a discrete image of the original, characterized in that said signal is obtained through the summation of several primary signals, where at least one primary signal is proportional to the sum, calculated over a first domain that entirely or partially fills said regions, of all products of the local light intensity in each point of said first domain multiplied by a factor with an unvarying sign and an absolute value which varies as a function of the position of said point in said first domain, and where at least one other primary signal is proportional to the sum, calculated over a second domain different from the first, of all similar products of the local light intensities in said second domain multiplied by a second factor which has an unvarying sign opposite to that of said first factor.

Claim 8

Method for optically scanning a sequence of regions throughout an original for generating an electrical signal dependent both upon the light intensity and its distribution within the region being scanned in order to produce a discrete image of the original, characterized in that said signal is obtained through the summation of several primary signals, where at least one primary signal is proportional to the sum, calculated over a first domain that entirely or partially fills said regions, of all products of the local light intensity in each point of said first domain multiplied by a factor with an unvarying sign and an absolute value which varies as a function of the position of said point in said first domain, and where at least one other primary signal is proportional to the sum, calculated over a second domain different from the first, of all similar products of the local light intensities in said second domain multiplied by a second factor which has an unvarying sign opposite to that of said first factor.

Claim 9

Method according to claim 6, characterized by the use of exactly two primary signals.

Claim 10

Method according to claim 6, characterized in that at least one factor varies continuously within its domain.

Claim 11

Method according to claim 6, characterized in that at least two domains with factors of opposite signs overlap each other.

Claim 12

Method according to claim 6, characterized by a rotational symmetry of the values of the factors.

Claim 13

Method according to claim 6, characterized in that the domains are concentric.