Mark reader

Claim 1

A system for indexing with a projection position a selected frame of a film roll having a plurality of frames and a plurality of frame marks, each mark associated with a frame and capable of modulating a light beam, including: means for moving the film along a defined path to thereby move successive film frames along a frame path intersecting the projection position and to move the marks along a mark path; means for generating a light beam intersecting the mark path and modulated by the frame marks traversing the beam as the film moves along its path; a first and a second detector disposed in the path of the modulated beam and spaced from each other along the mark path by a distance less than the maximum width of the modulated beam so that the first detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in a first direction along the mark path, but the second detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in the opposite direction along the mark path, each detector providing a mark detection signal when illuminated by the modulated beam; first and second means for nonlinearly transforming the mark detection signals of said first and second detector respectively to provide a respective first and second transformed signal; means for comparing the transformed signals and for providing on the basis of the comparison a signal indicating the direction of movement of the film along its path and the number of frames that have traversed the projection position, and means responsive to said signal to stop the film when a selected film frame is indexed with the projection position.

Claim 2

A system for indexing with a projection position a selected frame of a film roll having a plurality of frames and a plurality of frame marks, each mark associated with a frame and capable of modulating a light beam, including: means for moving the film along a defined path to thereby move successive film frames along a frame path intersecting the projection position and to move the marks along a mark path; means for generating a light beam intersecting the mark path and modulated by the frame marks traversing the beam as the film moves along its path; a first and a second detector disposed in the path of the modulated beam and spaced from each other along the mark path by a distance less than the maximum width of the modulated beam so that the first detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in a first direction along the mark path, but the second detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in the opposite direction along the mark path, each detector providing a mark detection signal when illuminated by the modulated beam; first and second means for nonlinearly transforming the mark detection signals of said first and second detector respectively to provide a respective first and second transformed signal; means for comparing the transformed signals and for providing on the basis of the comparison a signal indicating the direction of movement of the film along its path and the number of frames that have traversed the projection position, and means responsive to said signal to stop the film when a selected film frame is indexed with the projection position.

Claim 3

A system for indexing with a projection position a selected frame of a film roll having a plurality of frames and a plurality of frame marks, each mark associated with a frame and capable of modulating a light beam, including: means for moving the film along a defined path to thereby move successive film frames along a frame path intersecting the projection position and to move the marks along a mark path; means for generating a light beam intersecting the mark path and modulated by the frame marks traversing the beam as the film moves along its path; a first and a second detector disposed in the path of the modulated beam and spaced from each other along the mark path by a distance less than the maximum width of the modulated beam so that the first detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in a first direction along the mark path, but the second detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in the opposite direction along the mark path, each detector providing a mark detection signal when illuminated by the modulated beam; first and second means for nonlinearly transforming the mark detection signals of said first and second detector respectively to provide a respective first and second transformed signal; means for comparing the transformed signals and for providing on the basis of the comparison a signal indicating the direction of movement of the film along its path and the number of frames that have traversed the projection position, and means responsive to said signal to stop the film when a selected film frame is indexed with the projection position.

Claim 4

A system for indexing with a projection position a selected frame of a film roll having a plurality of frames and a plurality of frame marks, each mark associated with a frame and capable of modulating a light beam, including: means for moving the film along a defined path to thereby move successive film frames along a frame path intersecting the projection position and to move the marks along a mark path; means for generating a light beam intersecting the mark path and modulated by the frame marks traversing the beam as the film moves along its path; a first and a second detector disposed in the path of the modulated beam and spaced from each other along the mark path by a distance less than the maximum width of the modulated beam so that the first detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in a first direction along the mark path, but the second detector and then both detectors are illuminated by the modulated beam as a mark traverses the beam moving in the opposite direction along the mark path, each detector providing a mark detection signal when illuminated by the modulated beam; first and second means for nonlinearly transforming the mark detection signals of said first and second detector respectively to provide a respective first and second transformed signal; means for comparing the transformed signals and for providing on the basis of the comparison a signal indicating the direction of movement of the film along its path and the number of frames that have traversed the projection position, and means responsive to said signal to stop the film when a selected film frame is indexed with the projection position.

Claim 7

A system comprising: a film having a plurality of frames and a corresponding plurality of frame marks, each mark associated with a frame and each mark capable of modulating a light beam impinging thereon; means for selectively moving the film in a forward and in a reverse direction to thereby move successive frames through a projection position and the corresponding marks through a mark detecting position; means for generating a mark detecting beam intersecting the mark detecting position and modulated by marks intersecting said mark detecting position to provide a modulated beam; a first and a second detector disposed in the path of the modulated beam and spaced apart from each other along a direction transverse to the beam by a distance less than the maximum width of the modulated beam impinging on the detectors, whereby the first and then both detectors are illuminated by the modulated beam as a mark traverses the beam while the film moves in the forward direction, but the second detector and then both detectors are illuminated by the beam as a mark traverses the detecting position while the film moves in the reverse direction, each detector providing a mark detection signal when illuminated by the modulated beam; firsT and second means for nonlinearly transforming said mark detection signals to provide transformed signals; means for comparing the transformed signals and for providing, on the basis of the comparison, a first direction count signal when the transformed signals indicate that the film is moving in the forward direction and a second direction count signal when the transformed signals indicate that the film is moving in the reverse direction; a bidirectional counter counting in a first and a second direction respectively in response to said first direction and second direction count signals; a keyboard for providing a signal indicating the number of a desired film frame; a comparator comparing the signal provided by the keyboard and a signal corresponding to the contents of the counter and for providing a coincidence signal when the two compared signals have a defined relationship; and means responsive to said coincidence signal for stopping the film to thereby index a desired frame with the projection position.

Claim 8

A system comprising: a film having a plurality of frames and a corresponding plurality of frame marks, each mark associated with a frame and each mark capable of modulating a light beam impinging thereon; means for selectively moving the film in a forward and in a reverse direction to thereby move successive frames through a projection position and the corresponding marks through a mark detecting position; means for generating a mark detecting beam intersecting the mark detecting position and modulated by marks intersecting said mark detecting position to provide a modulated beam; a first and a second detector disposed in the path of the modulated beam and spaced apart from each other along a direction transverse to the beam by a distance less than the maximum width of the modulated beam impinging on the detectors, whereby the first and then both detectors are illuminated by the modulated beam as a mark traverses the beam while the film moves in the forward direction, but the second detector and then both detectors are illuminated by the beam as a mark traverses the detecting position while the film moves in the reverse direction, each detector providing a mark detection signal when illuminated by the modulated beam; firsT and second means for nonlinearly transforming said mark detection signals to provide transformed signals; means for comparing the transformed signals and for providing, on the basis of the comparison, a first direction count signal when the transformed signals indicate that the film is moving in the forward direction and a second direction count signal when the transformed signals indicate that the film is moving in the reverse direction; a bidirectional counter counting in a first and a second direction respectively in response to said first direction and second direction count signals; a keyboard for providing a signal indicating the number of a desired film frame; a comparator comparing the signal provided by the keyboard and a signal corresponding to the contents of the counter and for providing a coincidence signal when the two compared signals have a defined relationship; and means responsive to said coincidence signal for stopping the film to thereby index a desired frame with the projection position.