Automatic focusing system

Claim 2

An automatic focusing system comprising: a) detecting means for detecting, from an image signal, a predetermined signal component which varies with the state of focus; b) computing means for computing and producing output control information by computing a degree to which information based on said signal component detected by said detecting means conforms to predetermined conditions; and c) focus control means for adjusting focus on the basis of the output control information produced from said computing means.

Claim 3

A system according to claim 1, wherein said de­tecting means is arranged to detect a plurality of signals which vary according to the state of focus and have dif­ferent characteristics from each other.

Claim 4

A system according to claim 2, wherein said plu­rality of signals include a high-frequency component of said image signal and an edge signal which corresponds to the width of the edge part of an object image.

Claim 5

A system according to claim 1, wherein said pre­determined conditions exist in a plural number, and wherein said computing means is arranged to collate with said predetermined conditions a plurality of pieces of information including detected information output from said detecting means, to compute a degree to which said plurality of pieces of information conform to said predetermined conditions, and to obtain output control information for driving and controlling said focus control means.

Claim 6

A system according to claim 4, wherein said plu­rality of pieces of information include a high-frequency component of said image signal, an edge signal corresponding to the width of the edge part of an object image and a signal obtained by differentiating said edge signal.

Claim 7

A system according to claim 4, wherein said com­puting means is arranged to determine the arrival of said focus control means at an in-focus point by performing a computing operation and to bring said focus control means to a stop upon its arrival at said in-focus point.

Claim 8

A system according to claim 4, wherein said com­puting means is arranged to determine, by performing a computing operation, whether or not said focus control means is allowed to restart a focus adjusting action thereof after said focus control means has stopped upon its arrival at an in-focus point.

Claim 9

A system according to claim 7, wherein said com­puting means is arranged to determine the restart of said focus control means by taking into consideration a change in the detected information when said focus control means is shifted to a minute extent according to information detected by said detecting means, a temporal change in an object image itself, a temporal change in the distance of the object image and a change in shooting conditions such as the depth of field.

Claim 10

A system according to claim 8, wherein said com­puting means is arranged to compute and obtain a degree to which said plurality of pieces of information conform to a plurality of preset and predetermined rules from a plurality of membership functions and to perform, on the basis of the result of the computation, an output information computing operation by using a fuzzy inference algorithm.

Claim 11

A system according to claim 1, wherein said fo­cus control means is arranged to adjust focus by shifting the position of a focusing lens.

Claim 12

An automatic focusing system comprising: a) focus adjusting means for adjusting focus on the basis of a predetermined signal component which is extracted from an image signal and varies according to the state of focus; and b) restart determining means for restarting a focus adjusting action of said focus adjusting means according to a change in the state of focus after said focus adjusting means is brought to a stop upon its arrival at an in-focus point, said restart determining means being arranged to determine whether to restart said focus adjusting means or not on the basis of a degree to which detected information including said signal component which varies according to the state of focus conforms to a plurality of preset conditions.

Claim 13

An automatic focusing system comprising: a) focus adjusting means for adjusting focus on the basis of a predetermined signal component which is extracted from an image signal and varies according to the state of focus; and b) restart determining means for restarting a focus adjusting action of said focus adjusting means according to a change in the state of focus after said focus adjusting means is brought to a stop upon its arrival at an in-focus point, said restart determining means being arranged to determine whether to restart said focus adjusting means or not on the basis of a degree to which detected information including said signal component which varies according to the state of focus conforms to a plurality of preset conditions.

Claim 14

A system according to claim 11, wherein said plurality of conditions are a plurality of rules previously set for said detected information, and wherein said restart determining means is arranged to obtain, on the basis of a plurality of membership functions, a degree to which said detected information satisfies said plurality of rules and to determine whether or not the state of focus deviates from an in-focus point on the basis of information on said degree.

Claim 15

A system according to claim 12, wherein said re­start determining means uses a fuzzy inference algorithm.

Claim 16

A system according to claim 13, wherein said detected information includes at least a high-frequency component signal of said image signal, an edge signal corresponding to the edge width of an object image and a signal obtained by differentiating said edge signal.

Claim 17

A system according to claim 13, wherein said restart determining means is arranged to determine the restart of said focus adjusting means by taking into consideration a change in the detected information when said focus adjusting means is shifted to a minute extent according to the detected information, a temporal change in an object image, a temporal change in the distance of the object image and a change in shooting conditions such as the depth of field.

Claim 18

A system according to claim 13, wherein said plurality of membership functions used by the restart determining means include input membership functions and output membership functions, a degree to which said detected information satisfies said plurality of rules is obtained on said plurality of input membership functions, and output control information is obtained by performing, on said output membership functions, a barycentric computing operation on said degree thus obtained.

Claim 19

A system according to claim 11, wherein said focus adjusting means includes a focusing lens.

Claim 20

An automatic focusing system comprising: a) detecting means for detecting from an image signal a signal component which varies according to the state of focus; b) focus adjusting means for adjusting focus by varying the state of focus; and c) control means arranged to collate, with pre­determined conditions, detected information based on said signal component detected by said detecting means, to compute control information for controlling a focus adjusting action of said focus adjusting means on the basis of a degree to which said detected information conforms to said conditions and to control said focus adjusting means on the basis of said control informa­tion thus computed.

Claim 21

An automatic focusing system comprising: a) detecting means for detecting from an image signal a signal component which varies according to the state of focus; b) focus adjusting means for adjusting focus by varying the state of focus; and c) control means arranged to collate, with pre­determined conditions, detected information based on said signal component detected by said detecting means, to compute control information for controlling a focus adjusting action of said focus adjusting means on the basis of a degree to which said detected information conforms to said conditions and to control said focus adjusting means on the basis of said control informa­tion thus computed.

Claim 22

A system according to claim 18, wherein said control information computed by said control means is a driving speed of said focus adjusting means.

Claim 23

A system according to claim 19, wherein said detected information includes at least a high-frequency component signal of said image signal, an edge signal representing the edge width of an object image and a signal obtained by differentiating said edge signal, and wherein said control means is arranged to compute and control the speed of said focus adjusting means by using said signals as input information.

Claim 24

A system according to claim 20, wherein said conditions include a plurality of rules previously set for said detected information, and wherein said control means is arranged to obtain a degree to which said detected information satisfies said plurality of rules on the basis of a plurality of membership functions and to compute the driving speed of said focus adjusting means on the basis of information on said degree thus obtained.

Claim 25

A system according to claim 21, wherein said plurality of membership functions used by said control means include input membership functions and output membership functions, a degree to which said input information satisfies said plurality of rules is obtained on said plurality of input membership functions, and speed control information is obtained by performing, on said output membership functions, a barycentric computing operation on said degree thus obtained.

Claim 26

A system according to claim 22, wherein said control means uses a fuzzy inference algorithm.

Claim 27

A system according to claim 23, wherein said control means is arranged to drive said focus adjusting means at a higher speed accordingly as the state of focus deviates to a greater extent from an in-focus point and at a lower speed accordingly as the state of focus becomes closer to said in-focus point.

Claim 28

A system according to claim 18, wherein said focus adjusting means is a focusing lens.

Claim 29

A video camera comprising: a) image sensing means for photo-electrically converting an object image formed on an image sensing plane by a focusing lens to produce an image signal; b) detecting means for detecting from said image signal a signal component which varies according to the state of focus; c) focus adjusting means for adjusting focus by driving said focusing lens to vary the state of focus of the object image formed on said image sensing plane; d) control means arranged to collate detected information based on said signal component detected by said detecting means with present and predetermined rules, to compute the driving direction and the driving speed of said focusing lens on the basis of a degree to which said detected information conforms to said rules, and to control the driving of said focusing lens on the basis of the result of computation; and e) restart determining means for restarting said focus adjusting means by detecting that the position of said focusing lens again deviates from an in-focus point after said focusing lens is brought to a stop at said in-focus point.

Claim 30

A video camera comprising: a) image sensing means for photo-electrically converting an object image formed on an image sensing plane by a focusing lens to produce an image signal; b) detecting means for detecting from said image signal a signal component which varies according to the state of focus; c) focus adjusting means for adjusting focus by driving said focusing lens to vary the state of focus of the object image formed on said image sensing plane; d) control means arranged to collate detected information based on said signal component detected by said detecting means with present and predetermined rules, to compute the driving direction and the driving speed of said focusing lens on the basis of a degree to which said detected information conforms to said rules, and to control the driving of said focusing lens on the basis of the result of computation; and e) restart determining means for restarting said focus adjusting means by detecting that the position of said focusing lens again deviates from an in-focus point after said focusing lens is brought to a stop at said in-focus point.

Claim 31

A video camera according to claim 26, wherein said detected information includes at least a high-frequency component signal of said image signal, an edge signal representing the edge width of the object image and a signal obtained by differentiating said edge signal, and wherein said control means is arranged to compute and control the speed of said focus adjusting means by using said signal as input information.

Claim 32

A video camera according to claim 27, wherein said control means is arranged to obtain a degree to which said detected information satisfies said plurality of rules on the basis of a plurality of membership functions and to compute the driving speed of said focus adjusting means on the basis of information on said degree.

Claim 33

A video camera according to claim 28, wherein said plurality of membership functions used by said con­trol means include input membership functions and output membership functions, a degree to which said input information satisfies said rules is obtained on said plurality of input membership functions, and speed control information is obtained by performing, on said output membership functions, a barycentric computing operation on said degree.

Claim 34

A video camera according to claim 29, wherein said control means uses a fuzzy inference algorithm.

Claim 35

A video camera according to claim 26 or 30, wherein said restart determining means is arranged to col­late, with preset and predetermined rules, detected information based on said signal component detected by said detecting means, to determine whether to restart said focusing lens or not and determine the direction of the restart on the basis of a degree to which said detected information conforms to said rules, and to control said focusing lens on the basis of the result of computation.

Claim 36

A video camera according to claim 31, wherein said rules are a plurality of rules previously set for said detected information, and wherein said restart determining means is arranged to obtain, on a plurality of membership functions, a degree to which said detected information satisfies said plurality of rules and to determine whether or not said focusing lens has deviated from an in-focus point on the basis of information on said degree.

Claim 37

A camera according to claim 32, wherein said re­start determining means uses a fuzzy inference algorithm.

Claim 38

An automatic focus adjusting system comprising: a) detecting means for detecting from an image signal a signal component which varies according to the state of focus; b) focus adjusting means for adjusting focus by varying the state of focus; and c) computing means arranged to collate de­tected information based on said signal component detected by said detecting means with preset and predetermined conditions, to compute control information to be used for controlling a focus adjusting action of said focus adjusting means on the basis of a degree to which said detected information satisfies said conditions and to supply said control information to said focus adjusting means; and d) escape means for causing said focus adjust­ing means to escape from any control performed on the basis of the output of said computing means when said detected information does not satisfy said predetermined conditions.

Claim 39

An automatic focus adjusting system comprising: a) detecting means for detecting from an image signal a signal component which varies according to the state of focus; b) focus adjusting means for adjusting focus by varying the state of focus; and c) computing means arranged to collate de­tected information based on said signal component detected by said detecting means with preset and predetermined conditions, to compute control information to be used for controlling a focus adjusting action of said focus adjusting means on the basis of a degree to which said detected information satisfies said conditions and to supply said control information to said focus adjusting means; and d) escape means for causing said focus adjust­ing means to escape from any control performed on the basis of the output of said computing means when said detected information does not satisfy said predetermined conditions.

Claim 40

A system according to claim 34, wherein said control information computed by said computing means re­lates to the driving speed of said focus adjusting means.

Claim 41

A system according to claim 35, wherein said detected information includes at least a high-frequency component signal of said image signal, an edge signal representing the edge width of the object image and a signal obtained by differentiating said edge signal, and said computing means is arranged to compute and control the speed of said focus adjusting means by using said signals as input information.

Claim 42

A system according to claim 36, wherein said conditions are a plurality of rules previously set for said detected information, and wherein said computing means is arranged to obtain a degree to which said detected information satisfies said plurality of rules on the basis of a plurality of membership functions and to compute the driving speed of said focus adjusting means on the basis of information on said degree.

Claim 43

A system according to claim 37, wherein said plurality of membership functions used by said computing means include input membership functions and output membership functions, a degree to which said input information satisfies said rules is obtained on said input membership functions, and speed control information is obtained by performing a barycentric computing operation on said degree on the basis of said output membership functions.

Claim 44

A system according to claim 38, wherein said computing means is arranged to drive said focus adjusting means at a higher speed accordingly as the state of focus deviates to a greater extent from an in-focus point and at a lower speed accordingly as the state of focus becomes closer to said in-focus point.

Claim 45

A system according to claim 34 or 39, wherein said escape means is arranged to stop any control from being performed on the basis of the result of the computing operation of said computing means and to shift the mode of control to a restart determining mode when said detected information does not satisfy said predetermined conditions.

Claim 46

A system according to claim 40, wherein said escape means is arranged to shift the mode of control from a speed control mode to the restart determining mode when speed control becomes impossible while said detected information does not satisfy said predetermined conditions.

Claim 47

A focusing device which comprises; focus variation means for adjusting the focus of an image in response to a control signal; and focus control means arranged to generate from the image signal a plurality of different focus-responsive signals, and to generate a control signal for controlling the focus varying means in response to the detection of a predetermined condition being met by the focus-responsive signals in combination.

Claim 48

A focusing device which comprises; focus variation means for adjusting the focus of an image in response to a control signal; and focus control means arranged to generate from the image signal a plurality of different focus-responsive signals, and to generate a control signal for controlling the focus varying means in response to the detection of a predetermined condition being met by the focus-responsive signals in combination.

Claim 49

A device according to claim 42, in which the focus control means is arranged to compute, from the focus-responsive signals, a plurality of polyvalent signals indicating the degree of likelihood of correspondence to respective predetermined classes, and the control signal is generated in response to combinations of the said polyvalent signals.

Claim 50

A focusing device having a focus-hunting mode in which the focus of an image signal is adjusted in response to signals derived therefrom, the device being arranged, on the occurrence of predetermined conditions in the said derived signal, to halt and restart the focus hunting mode.

Claim 51

A focusing device having a focus-hunting mode in which the focus of an image signal is adjusted in response to signals derived therefrom, the device being arranged, on the occurrence of predetermined conditions in the said derived signal, to halt and restart the focus hunting mode.

Claim 56

A focus controller arranged to generate a signal for controlling a focus varying motor, arranged to vary the motor speed in response to at least one focus-responsive signal derived from the focused image.

Claim 57

A focus controller arranged to generate a signal for controlling a focus varying motor, arranged to vary the motor speed in response to at least one focus-responsive signal derived from the focused image.

Claim 58

A focus control system having a focus control mode and a trial focusing mode arranged to select between said modes in response to a predetermined condition, which condition is detected by a computing device executing a fuzzy inference algorithm upon an input signal derived from an image.

Claim 59

A focus control system having a focus control mode and a trial focusing mode arranged to select between said modes in response to a predetermined condition, which condition is detected by a computing device executing a fuzzy inference algorithm upon an input signal derived from an image.