Method for producing a geometrical transformation on a video image and devices for carrying out said method
First Claim
1. A method for producing a geometrical transformation on a video image designated as an initial image, comprising the steps of:
- identifying each point of the initial image by a plurality of first coordinates (X, Y, O) in a first cartesian reference frame which is designated as a movable reference frame and is related to the initial image;
representing each point of the initial image by a digital word;
storing the digital words representing each point of the initial image at a plurality of addressable locations in a storage device having address inputs and a data output, so that a digital word corresponding to the each point and having coordinates (X, Y, O) in the initial image is delivered when address values corresponding to the each point are applied to the storage device address inputs;
performing a transformation of the initial image using predetermined tranformation parameters to yield a transformed image;
identifying each point of the transformed image by a plurality of second coordinates (X3, Y3, O) in a second cartesian reference frame which is related to the transformed image and is designated as a fixed reference frame;
determining a relationship between the second coordinates and the first coordinates, based on the transformation parameters and calculating one computed address value; and
representing each point of the transformed image by a digital word supplied from the storage device by applying computed address values to the address inputs of said storage device, said computed values being computed as a sum of the computed address value of second coordinates (X3, Y3, O) of said point and, an increment value.
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Abstract
Special effects are produced on video images by means of a method of geometrical transformation which can involve a translation, a rotation, an affine transformation or an effect of perspective. The method consists:
in locating each point of the initial image by means of coordinates (X, Y, O) in a cartesian reference frame designated as a movable reference frame and related to the initial image;
in representing each point of the initial image by a binary word;
in storing the initial image in a storage device having two read address inputs and one data output, the function of the device being to deliver a binary word corresponding to the point with coordinates (X, Y, O) in the initial image when read address values X and Y are applied respectively to the two inputs:
in causing each point of the transformed image resulting from an initial-image transformation to be located by means of coordinates (X3, Y3, O) in a cartesian reference frame which is related to the transformed image and designated as a fixed reference frame;
in representing each point of the transformed image by a binary word M supplied by the storage device by applying values of X and Y to the read address inputs of the device, these values being computed as a function of the coordinates (X3, Y3, O) of said point and as a function of the geometrical transformation parameters.
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Citations
17 Claims
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1. A method for producing a geometrical transformation on a video image designated as an initial image, comprising the steps of:
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identifying each point of the initial image by a plurality of first coordinates (X, Y, O) in a first cartesian reference frame which is designated as a movable reference frame and is related to the initial image; representing each point of the initial image by a digital word; storing the digital words representing each point of the initial image at a plurality of addressable locations in a storage device having address inputs and a data output, so that a digital word corresponding to the each point and having coordinates (X, Y, O) in the initial image is delivered when address values corresponding to the each point are applied to the storage device address inputs; performing a transformation of the initial image using predetermined tranformation parameters to yield a transformed image; identifying each point of the transformed image by a plurality of second coordinates (X3, Y3, O) in a second cartesian reference frame which is related to the transformed image and is designated as a fixed reference frame; determining a relationship between the second coordinates and the first coordinates, based on the transformation parameters and calculating one computed address value; and representing each point of the transformed image by a digital word supplied from the storage device by applying computed address values to the address inputs of said storage device, said computed values being computed as a sum of the computed address value of second coordinates (X3, Y3, O) of said point and, an increment value. - View Dependent Claims (2, 3, 4, 5)
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6. A method for producing a geometrical transformation of an initial video image, comprising the steps of:
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identifying each point of the video image by a first address in a first coordinate system; storing a digital word representing characteristics with each point in the video image at the first address; performing a transformation of the original image using predetermined transformation parameters to yield a transformed image; identifying each point in the transformed image by a second address in a second coordinate system; computing a value of an initial point in the transformed image; determining a first recurrence, which when added to a value of an adjacent point yields a value of a current point; determining each value of each point from the value of an adjacent point; and using such value as an address to access the stored digital word representing the characteristics of each point. - View Dependent Claims (7, 8, 9)
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10. An apparatus for performing a transformation on a video image, comprising:
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image memory means for storing a digital word representing characteristics of each point of an initial image; processing means for;
(1) determining initial values for a point of a transformed image, and (2) determining a recurrence value between each point and an adjacent point of the transformed image; andadding means for producing a current address from an adjacent address by adding said recurrence value and one of (a) said initial value when said initial value is said adjacent address, and (b) the previous current address output by said adding means to thereby perform an adding operation between a recurrence value and the previous address used to produce a current address in real time. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification