Method and apparatus for comparison

Claim 3

The method of claim 1 wherein said step of producing a plurality of groups of independent potential levels comprises the steps of: generating a plurality of subgroups of currents in each group in response to said plurality of voltages; generating a plurality of groups of currents by summing the currents in each subgroup of currents in each group, and producing said plurality of groups of independent potential levels from said plurality of groups of currents.

Claim 6

The method of claim 3 wherein said step of producing a plurality of groups of independent potential levels comprises the steps of: generating groups of a first plurality of currents proportional to said second plurality of voltages; summing said first plurality of currents to form corresponding groups of a second plurality of currents; and producing said groups of independent potential levels from said second plurality of currents.

Claim 7

The mEthod of claim 4 wherein said groups are equal in number to the number of predetermined types.

Claim 8

The method of claim 5 wherein said step of generating groups of a first plurality of currents comprises applying said second plurality of voltages to a plurality of groups of resistor networks, each resistor network comprising a plurality of resistors, such that said first plurality of currents flow in said plurality of resistors, and wherein the number of resistor networks in each group is approximately equal to the number of said second plurality of voltages.

Claim 9

The method of claim 6 wherein said step of summing said first plurality of currents comprises applying said first plurality of currents that flow in said plurality of resistors in each resistor network to a summation resistor in said resistor network, and wherein each said resistor network produces a corresponding independent potential level.

Claim 10

The method of claim 7 wherein the values of said plurality of groups of resistors are predetermined in such a way, that the standard deviation of each of said independent potential levels generated at said summation resistor becomes minimal for a predetermined representative sample set of objects of predetermined type.

Claim 11

The method of claim 7 wherein said step of comparing said independent potential levels comprises applying each independent potential level in each group to an AND-gate-threshold circuit associated with that group, and wherein said AND-gate-threshold circuit has a threshold level determined by said second plurality of voltages such that said predetermined levels are constrained to a relatively small interval about a value.

Claim 12

The method of claim 9 wherein said step of preventing more than one favorable comparison comprises the steps of applying the output from each combination AND gate-threshold circuit to an associated blocking circuit and to a further combination AND gate-threshold circuit, and applying an output from said further AND gate-threshold circuit to each said associated blocking circuit, there by inhibiting each blocking circuit from producing an output; and wherein said first plurality of voltages is equal in number to said resistor networks in each said group.

Claim 13

In character recognition apparatus for identifying an unknown character whose features may vary as being one of a predetermined plurality of types, said character recognition apparatus including photosensor means for detecting said unknown character and generating voltages in response thereto, the improvement comprising: a plurality of groups of network means, each group corresponding to a predetermined type and comprising plural networks, each network producing an independent potential level; said plural networks each including plural resistance means having values predetermined in such a way, that the standard deviation of each of said independent potential levels becomes minimal for a predetermined representative sample set of objects of each type; means coupling said generated voltages to said resistance means; threshold circuit means in each group for comparing each produced independent potential level to predetermined threshold levels; first means responsive to said threshold circuit means for indicating the identity of said unknown character; and second means responsive to said threshold circuit means for preventing more than one indication of the identity of said unknown character by said first means responsive to said threshold circuit means.

Claim 14

In character recognition apparatus for identifying an unknown character whose features may vary as being one of a predetermined plurality of types, said character recognition apparatus including photosensor means for detecting said unknown character and generating voltages in response thereto, the improvement comprising: a plurality of groups of network means, each group corresponding to a predetermined type and comprising plural networks, each network producing an independent potential level; said plural networks each including plural resistance means having values predetermined in such a way, that the standard deviation of each of said independent potential levels becomes minimal for a predetermined representative sample set of objects of each type; means coupling said generated voltages to said resistance means; threshold circuit means in each group for comparing each produced independent potential level to predetermined threshold levels; first means responsive to said threshold circuit means for indicating the identity of said unknown character; and second means responsive to said threshold circuit means for preventing more than one indication of the identity of said unknown character by said first means responsive to said threshold circuit means.

Claim 15

The improvement of claim 11 wherein said first means responsive to said threshold circuit means indicates the identity of said unknown character when the standard deviations of said independent potential levels are within predetermined thresholds.

Claim 16

The improvement of claim 12 wherein said resistance means in each said network comprises a plurality of resistors equal in number to the number of said generated voltages, and said resistors are coupled at one enD thereof to said generated voltages by a plurality of terminal pairs, said terminal pairs being equal in number to the number of said resistors, and at another end thereof to a common output terminal.

Claim 17

The improvement of claim 13 wherein said threshold circuit means in each group comprises a combination AND gate-threshold circuit whose threshold level is proportional to said generated voltages such that said predetermined levels are constrained to a relatively small interval about a value; said combination AND gate-threshold circuit being coupled to each said common output terminal in said group.

Claim 18

The improvement of claim 14 wherein said first means responsive to said threshold circuit means comprises a plurality of blocking circuits, each said blocking circuit connected to a combination AND gate-threshold circuit; and wherein said second means responsive to said threshold circuit means comprises a further combination AND gate-threshold circuit having a plurality of inputs connected to said combination AND gate-threshold circuits, and having an output connected to said blocking circuits whereby said blocking circuits are activated to inhibit said indication of the identity of said unknown character upon the generation of a signal by said further combination AND gate-threshold circuit.

Claim 21

Apparatus for classifying an unknown condition represented by n features which are subject to variations as being one of a predetermined type comprising: means for generating n electrical quantities proportional to said n features; means coupled to said means for generating for deriving two oppositely phased voltages from each of said n electrical quantities; a plurality of groups of n resistor networks, each of said groups representing a predetermined type of condition, wherein each of said resistor networks in each of said groups comprises n combination resistors and a summation resistor connected to a common point whereat potential levels are produced, said summation resistors in each group being connected in common relationship; said combination resistors of said n resistor networks in a group having values established in accordance with the eigenvectors of the covariancematrix ascertained by predetermined variations among the type of condition represented by said group, such that the resistors of the ith resistor network in said group are proportional to the components of the ith eigenvector of the covariancematrix whereby said potential levels are independent of each other and the standard deviations thereamong are minimal when said unknown condition corresponds to the type represented by said group; means for coupling said means for deriving to said coMbination resistors such that each of said combination resistors has a derived voltage applied thereto; means associated with each said group and coupled to said common points therein for determining whether said potential levels produced thereat lie within prescribed limits; and means coupled to said means for determining for indicating the outputs produced thereby.

Claim 22

Apparatus for classifying an unknown condition represented by n features which are subject to variations as being one of a predetermined type comprising: means for generating n electrical quantities proportional to said n features; means coupled to said means for generating for deriving two oppositely phased voltages from each of said n electrical quantities; a plurality of groups of n resistor networks, each of said groups representing a predetermined type of condition, wherein each of said resistor networks in each of said groups comprises n combination resistors and a summation resistor connected to a common point whereat potential levels are produced, said summation resistors in each group being connected in common relationship; said combination resistors of said n resistor networks in a group having values established in accordance with the eigenvectors of the covariancematrix ascertained by predetermined variations among the type of condition represented by said group, such that the resistors of the ith resistor network in said group are proportional to the components of the ith eigenvector of the covariancematrix whereby said potential levels are independent of each other and the standard deviations thereamong are minimal when said unknown condition corresponds to the type represented by said group; means for coupling said means for deriving to said coMbination resistors such that each of said combination resistors has a derived voltage applied thereto; means associated with each said group and coupled to said common points therein for determining whether said potential levels produced thereat lie within prescribed limits; and means coupled to said means for determining for indicating the outputs produced thereby.

Claim 23

The apparatus of claim 17 wherein said common point has connected thereto one terminal of an additional resistor, the other terminal thereof adapted to be supplied with an additional voltage derived from said oppositely phased voltages whereby said prescribed limits comprises a relatively small interval about a zero level.

Claim 24

A comparator for use with character recognition apparatus which identifies a presented character as being one of a plurality of types, comprising: means for generating voltages proportional to the features of said presented character; a plurality of groups of resistance means, each group of resistance means being associated with one of said types and each group of resistance means being selectively connected to said means for generating voltages, each group of resistance means being responsive to said means for generating voltages for producing a plurality of independent potential levels; means for comparing each of the plurality of independent potential levels of each group with predetermined threshold levels; and means for identifying said presented character as being one of said plurality of types when each of the independent potential levels in the group associated with said one type is within said predetermined threshold levels.

Claim 25

A comparator for use with character recognition apparatus which identifies a presented character as being one of a plurality of types, comprising: means for generating voltages proportional to the features of said presented character; a plurality of groups of resistance means, each group of resistance means being associated with one of said types and each group of resistance means being selectively connected to said means for generating voltages, each group of resistance means being responsive to said means for generating voltages for producing a plurality of independent potential levels; means for comparing each of the plurality of independent potential levels of each group with predetermined threshold levels; and means for identifying said presented character as being one of said plurality of types when each of the independent potential levels in the group associated with said one type is within said predetermined threshold levels.

Claim 26

Character recognition apparatus for identifying an unknown character whose features may vary is being one of a predetermined plurality of types, said features being represented by n voltages, comprising: voltage generating means responsive to said n voltages for generating two oppositely phased voltages from each said n voltages; at most n resistor networks associated with each of said predetermined plurality of types, each resistor network comprised of at most n combination resistors and a summation resistor, said at most n combination resistors and said summation resistor in a network exhibiting a common connection between first terminals thereof, the second terminal of each combination resistor in a network being supplied with a voltage of selected phase generated by said voltage generating means; an AND-gate-threshold means associated with each of said predetermined plurality of types, each AND gate threshold means having n input terminals coupled to the n common connections of the at most n resistor networks associated with a corresponding one of said predetermined plurality of types for determining if each of the voltages developed at said n common connections are within predetermined threshold levels; and decision logic means coupled to the output terminal of each AND-gate-threshold means for indicating the identity of said unknown character if all of said developed voltages of said at most n resistor networks associated with one of said predetermined plurality of types are within their predetermined threshold levels.

Claim 27

Character recognition apparatus for identifying an unknown character whose features may vary is being one of a predetermined plurality of types, said features being represented by n voltages, comprising: voltage generating means responsive to said n voltages for generating two oppositely phased voltages from each said n voltages; at most n resistor networks associated with each of said predetermined plurality of types, each resistor network comprised of at most n combination resistors and a summation resistor, said at most n combination resistors and said summation resistor in a network exhibiting a common connection between first terminals thereof, the second terminal of each combination resistor in a network being supplied with a voltage of selected phase generated by said voltage generating means; an AND-gate-threshold means associated with each of said predetermined plurality of types, each AND gate threshold means having n input terminals coupled to the n common connections of the at most n resistor networks associated with a corresponding one of said predetermined plurality of types for determining if each of the voltages developed at said n common connections are within predetermined threshold levels; and decision logic means coupled to the output terminal of each AND-gate-threshold means for indicating the identity of said unknown character if all of said developed voltages of said at most n resistor networks associated with one of said predetermined plurality of types are within their predetermined threshold levels.

Claim 28

The apparatus of claim 20 wherein said common connection in each resistor network is coupled to a further voltage generator by an additional resistor, the magnitude of the voltage generated by said further voltage generator and the magnitude of said additional resistor establishing said predetermined threshold levels at an approximately zero potential level.

Claim 29

The apparatus of claim 21 wherein said further voltage generator generates a substantially constant voltage.

Claim 30

The apparatus of claim 21 wherein said further voltage generator generates a voltage proportional to the sum of all said oppositely phased voltages.

Claim 31

The apparatus of claim 20 wherein all of said oppositely phased voltageS generated in response to said n voltages alternate in polarity at a frequency of at least 1,000 Hz.