Automatic focus adjusting system capable of adjusting focus of moving subject

An automatic focus adjusting apparatus comprising:

• photoelectric conversion means having, in at least a predetermined area, a plurality of light receiving elements in a two-dimensional array for receiving light beams respectively of a pair of images of a subject formed by a pair of light beams arrayed in a predetermined direction, from out of light beams of the subject;
• two-image distance calculating means for calculating a distance between the pair of images of the subject, based on an output of the pair of images from the photoelectric conversion means;
• predicting means for predicting a distance between the two images at a third time, based on two-image distances at a first time and a second time respectively, by repeatedly operating the two-image distance calculating means, wherein the first time, the second time and third time are different from each other;
• control means for outputting a lens driving signal based on an output from the predicting means, when a predicted value based on a calculation by the two-image distance calculating means does not meet a predetermined condition and also when the predicted value meets the predetermined condition as a result of carrying out a signal processing again by the two-image distance calculating means based on a signal from a changed light-receiving area positioned in a direction approximately orthogonal with the pair of light beams arrayed in the predetermined direction in the photoelectric conversion means;
• and
• Lens-driving means for driving an image pickup lens to focus the subject at the third time based on a lens-driving signal from the control means.

An automatic focus adjusting apparatus for adjusting a focus of an image pickup lens so as to focus an image of an image picked-up subject positioned in a detecting area in a predetermined longitudinal direction within a photographing screen, the automatic focus adjusting apparatus comprising:

• predicting means for making a prediction by calculation based on a result of a repeated detection of a focus;
• lens driving means for driving the image pickup lens based on a prediction so as to focus the subject at a certain point of time in future, according to a result of the predict calculation conducted by the predicting means;
• and
• control means for prohibiting the lens driving means from driving the image pickup lens based on a prediction when it is judged that there is a low level of reliability in the process of predict calculation by the predict calculating means, then for making the predict calculation means detect again the predict calculation by shifting the detection area to a direction approximately orthogonal with the longitudinal direction, and for making the lens driving means drive the image pickup lens when it is judged that there is a reasonable level of reliability in the focus detection.

An automatic focus adjusting apparatus comprising:

• image dividing means for dividing an image of an image picked-up subject into a pair of images;
• first and second groups of photoelectric conversion elements for receiving respectively light beams of the pair of images divided by the image dividing means;
• image move-amount detecting means for obtaining move amounts of images of the subject, for each of the pair of images divided by the image dividing means, based on image positions of the subject on the first and second groups of photoelectric conversion elements at mutually different first and second times;
• detection area shifting means for shifting an image detection area of the subject detected by the image move-amount-detecting means, to a direction approximately orthogonal with a direction in which the image is divided;
• image position predicting means for predicting positions of the images of the subject at a third time different from the first and second times, based on an output from the image move-amount detecting means;
• and
• Lens-driving means for driving a lens based on an output from the image position predicting means.

An automatic focus adjusting apparatus comprising:

• an image dividing section for dividing an image of an image picked-up subject into a pair of images;
• first and second groups of photoelectric conversion elements for receiving respectively light beams of the pair of images divided by the image dividing section;
• an image move-amount detecting section for obtaining a move of each of the pair of images of the subject divided by the image dividing section, based on image positions of the subject on the first and second groups of photoelectric conversion elements at mutually different first and second times;
• a detection area shifting section for shifting an image detection area of the subject detected by the image move-amount detecting section, to a direction approximately orthogonal with a direction in which the image is divided;
• an image position predicting section for predicting positions of the images of the subject at a third time different from the first and second times, based on an output from the image move-amount detecting section;
• and
• a lens driving section for driving a lens based on an output from the image position predicting section.

An automatic focus adjusting method comprising the steps of:

• dividing an image of an image picked-up subject into a pair of images;
• receiving light beams of the pair of divided images, by first and second groups of photoelectric conversion elements respectively;
• obtaining a move amount of each of the pair of divided images of the subject, based on image positions of the subject on the first and second groups of photoelectric conversion elements at mutually different first and second times;
• shifting an image detection area of the subject obtained in the step of obtaining image move amounts of the subject, to a direction approximately orthogonal with a direction in which the image is divided;
• predicting positions of the images of the subject at a third time different from the first and second times, based on the image move amounts of the subject;
• and
• driving a lens based on an output of the predicted image positions of the subject.