Conversion of multilevel digital data to binary data

Claim 1

A system for converting multilevel video data into binary video data using an adjustable threshold, comprising: analog-to-digital converting means for converting analog video data obtained by scanning an original into multilevel video data; threshold setting means connected to receive said multilevel digital video data for setting a threshold by taking a digitally weighted average of at least two averaged image densities each determined for each scanning line, said threshold setting means including a first arithmetic unit for determining an average image density for a single scanning line, a memory unit for storing two or more average image densities determined by said first arithmetic unit and a second arithmetic unit for determining a digitally weighted average of a predetermined number of average image densities stored in said memory unit, whereby said second arithmetic unit supplies said digitally weighted average as a threshold to be set; and binary converting means for converting said multilevel video data into binary video data using said digitally weighted average as a threshold.

Claim 2

A system for converting multilevel video data into binary video data using an adjustable threshold, comprising: analog-to-digital converting means for converting analog video data obtained by scanning an original into multilevel video data; threshold setting means connected to receive said multilevel digital video data for setting a threshold by taking a digitally weighted average of at least two averaged image densities each determined for each scanning line, said threshold setting means including a first arithmetic unit for determining an average image density for a single scanning line, a memory unit for storing two or more average image densities determined by said first arithmetic unit and a second arithmetic unit for determining a digitally weighted average of a predetermined number of average image densities stored in said memory unit, whereby said second arithmetic unit supplies said digitally weighted average as a threshold to be set; and binary converting means for converting said multilevel video data into binary video data using said digitally weighted average as a threshold.

Claim 7

A system for converting multilevel video data into binary video data using an adjustable threshold, comprising: analog-to-digital converter means for converting analog video data obtained by scanning an original into multilevel digital video data; threshold setting means connected to receive said multilevel digital video data for setting a threshold by taking a digitally weighted average of at least two averaged image densities each determined for each scanning line, said threshold setting means including a first processing unit for receiving said multilevel digital video data for determining an average image density of each scanning line, a plurality of serially connected latches each storing said average image density and a second processing unit connected to receive average image densities from said plurality of latches to determine a digitally weighted average of the average image densities; binary converting means for converting said multilevel video data into binary video data using said digitally weighted average as a threshold; and delaying means for delaying the supply of said multilevel video data to be converted into binary video data to said binary converting means.

Claim 8

A system for converting multilevel video data into binary video data using an adjustable threshold, comprising: analog-to-digital converter means for converting analog video data obtained by scanning an original into multilevel digital video data; threshold setting means connected to receive said multilevel digital video data for setting a threshold by taking a digitally weighted average of at least two averaged image densities each determined for each scanning line, said threshold setting means including a first processing unit for receiving said multilevel digital video data for determining an average image density of each scanning line, a plurality of serially connected latches each storing said average image density and a second processing unit connected to receive average image densities from said plurality of latches to determine a digitally weighted average of the average image densities; binary converting means for converting said multilevel video data into binary video data using said digitally weighted average as a threshold; and delaying means for delaying the supply of said multilevel video data to be converted into binary video data to said binary converting means.

Claim 9

A system for converting multilevel video data into binary video data using an adjustable threshold, comprising: analog-to-digital converting means for converting analog video data obtained by scanning an original into multilevel digital video data; threshold setting means connected to receive said multilevel digital video data for setting a threshold by taking a digitally weighted average of at least two averaged image densities each determined for each scanning line, said threshold setting means including a first processing unit for receiving said multilevel digital video data for determining at least two average image densities for predetermined sections of each scanning line, at least two sets of serially connected latches each set including a predetermined number of serially connected latches for each predetermined section of scanning line each latch storing said average image density of the corresponding section, a selector for allowing to pass the information from a selected set of serially connected latches and a second processing unit connected to said selector to determine a digitally weighted average based on the information supplied through said selector from said selected set of serially connected latches; binary converting means for converting said multilevel video data into binary video data using said digitally weighted average as a threshold; and delaying means for delaying the supply of said multilevel video data to be converted into binary video data to said binary converting means.

Claim 10

A system for converting multilevel video data into binary video data using an adjustable threshold, comprising: analog-to-digital converting means for converting analog video data obtained by scanning an original into multilevel digital video data; threshold setting means connected to receive said multilevel digital video data for setting a threshold by taking a digitally weighted average of at least two averaged image densities each determined for each scanning line, said threshold setting means including a first processing unit for receiving said multilevel digital video data for determining at least two average image densities for predetermined sections of each scanning line, at least two sets of serially connected latches each set including a predetermined number of serially connected latches for each predetermined section of scanning line each latch storing said average image density of the corresponding section, a selector for allowing to pass the information from a selected set of serially connected latches and a second processing unit connected to said selector to determine a digitally weighted average based on the information supplied through said selector from said selected set of serially connected latches; binary converting means for converting said multilevel video data into binary video data using said digitally weighted average as a threshold; and delaying means for delaying the supply of said multilevel video data to be converted into binary video data to said binary converting means.