System for spatially transforming images

• US 4,908,874 A
• Filed: 01/06/1986
• Issued: 03/13/1990
• Est. Priority Date: 04/11/1980
• Status: Expired due to Term

• Current Assignee: Ampex Corporation (Delta Information Systems, Inc.)
• Original Assignee: Ampex Corporation (Delta Information Systems, Inc.)
• Inventors: Gabriel, Steven A.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/816,176
• Time in Patent Office: 1,527 Days
• Field of Search: 382/41-47, 382/49, 382/54, 358/166, 358/167, 358/22, 358/282, 358/283, 364/572, 364/724
• US Class Current: 382/277
• CPC Class Codes: G06T 1/60 Memory management
• CPC Class Codes: G06T 3/40 Scaling of whole images or parts thereof, e.g. expanding or contracting
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403

Abstract

A system for spatially transforming images by separate transformation of each dimension of the image is exemplified by a raster scan television system which includes for each color component a transposing memory providing a change of scan direction from horizontal to vertical, a vertical transformation system transforming in the vertical direction the vertically scanned video information, a second transposing memory coupled to receive vertically transformed video information and provide a change of scan direction from vertical back to horizontal, and a horizontal transformation system coupled to horizontally transform the horizontally scanned video signal to produce a color component output signal. The transformation system is controlled by a transform composer and factorizor which receives input commands designating X and Y pretranslations, X and Y size control, Z axis rotation angles, and X and Y post translations to produce a commanded composite transformation which is then factored into horizontal and vertical components.

Claims

1. A system for electronically transforming input data samples corresponding to picture elements of an image, said transformation corresponding to transformation of said picture elements of said image from a source location to a target location in a two dimensional coordinate system in which two coordinates indicate position in respective first and second directions, said system comprising

a first memory coupled to receive a serial sequence of data samples corresponding to source locations serialized by scanning in said first direction, the first memory being selectively operable to output the data samples in the serial sequence in which they are received or in a serial sequence representing scanning in said second direction;

a first filter coupled to receive the data samples output from said first memory and to output a serial sequence of first filtered data samples for target locations in a filtered function of a plurality of the data samples corresponding to picture elements neighboring respective first source location coordinates, said sequence output by said first filter corresponding to scanning in the direction corresponding to the output of said first memory;

a second memory coupled to receive the serial sequence of first filtered data samples from the first filter scanned in the respective said direction and to output the first filtered data samples in scan line data sample sequence representing scanning in the other said direction;

a second filter coupled to receive the first filtered data samples output from said second memory and to output a serial sequence of second filtered data samples scanned in said other direction for target locations as a filtered function of a plurality of the first filtered data samples corresponding to picture elements neighboring second source location coordinates; and

first and second source address generators coupled to provide to the first and second filters serial sequences of respective first and second source addresses corresponding to respective serial sequences of coordinates in accordance with a desired transformation between the source and target locations.

2. A system according to claim 1 wherein said data samples correspond to two-field interlaced raster scan television images, further comprising a deinterlace filter disposed between the first memory and the first filter to receive the data samples output by the first memory corresponding to interlaced two-field images and to combine said data samples to effect deinterlacing of the interlaced two-field images into respective deinterlaced single-field images.

3. A system according to claim 1 for transforming a luminance component of the images, and two chrominance components of the images, said system comprising a said first memory and a said second memory in respect to each of said component of the images, with respective memories addressed in parallel by the output of said first and second address generators.

4. A system according to claim 1 wherein said plurality of data samples corresponding to picture elements neighboring respective first source location coordinates corresponds to respective pluralities of picture elements disposed before and after the respective source location coordinates in the respective scanning direction, and said plurality of first data samples corresponding to picture elements neighboring respective second source location coordinates corresponds to respective pluralities of picture elements disposed before and after the respective source location coordinates in the respective scanning direction.

5. A system according to any one of claims 1 to 4 comprising further means for transforming data samples corresponding to at least one other image at the same time, and a switcher coupled to receive transformed data samples corresponding to respective images and to output said transformed data samples in a selected combination.

6. An interpolation filter for a transformation system for transforming an array of video data samples in a single direction, said data samples corresponding to picture elements of an image arranged in a two dimensional coordinate system in which two coordinates indicate the position of a data sample in respective coordinate directions, said transformation system transforming video data samples from a source location to a target location and thereby transforming a source image defined by said video data samples into a transformed image, said system including means for providing a source location signal indicating successive data sample locations between which lies a source location for which an interpolated data sample is to be derived from said data samples, means for providing a phase signal indicating the relative position of said source cation between said successive data sample locations, and a size signal indicative of the size of the source image relative to the transformed image, said filter comprising

N memory modules, where N is a positive integer greater than 1;

means for storing data samples of the image in the N memory modules in such sequence that, within any span of N consecutive data samples corresponding to consecutive picture elements in said single direction, each data sample is stored in a unique memory module;

a memory address circuit coupled to receive said source location signal and in response thereto to address the memory modules to output N data samples therefrom corresponding to N locations disposed about said source location;

a coefficient store storing filter weighting coefficients defining a magnitude relationship between said N data samples and a filtered data sample corresponding to said source location, the coefficient store outputting N coefficients corresponding respectively to the N data samples in response to and dependent upon said size and phase signals; and

means for generating a filtered data sample as an interpolated data sample output in response to the N data samples and the N filter function coefficients corresponding thereto.

7. A filter for converting input video data samples corresponding to picture elements of an image into output data samples arranged in sequence with successive groups of output data samples corresponding to progressively smaller fractional-sized reproductions of the image, the picture elements being arranged in a two dimensinal coordinate system in which two coordinates indicate position of a picture element corresponding to an input data sample in respective coordinate directions, the picture elements of a reproduction of the image being arranged in rows in each respective coordinate direction, said filter comprising

a filter circuit responsive to successive filter input data samples corresponding to picture elements succeeding one another in rows in a given coordinate direction for producing respective filtered data samples corresponding to picture elements of a fractional-size reproduction of the image that is a fraction of the linear size of the image corresponding to the filter input data samples, the ratio of the number of said filtered data samples to the number of said filter input data samples being said same fraction,

means for applying input video data samples corresponding to the image as successive filter input data samples to said filter circuit in groups corresponding to picture elements in respective rows in said given direction according to predetermined succession,

means for successively and recursively applying to said filter circuit the respective filtered data samples corresponding to each said group as filter input data samples a predetermined number of times, and

output means for successively outputting data samples for each said group corresponding respectively to the image and successive fractional-size reproductions thereof.

8. A filter in accordance with claim 7 wherein said fraction is one-half.

10. A filter according to any one of claims 7 to 9 wherein said filter circuit includes means for operating upon two input data samples in parallel to produce said filtered data samples.

9. A filter for converting input video data samples corresponding to picture elements of an image into output data samples arranged in sequence with successive groups of output data samples corresponding to progressively smaller reproductions of the image, the picture elements being arranged in a two dimensional coordinate system in which two coordinates indicate position of a picture element corresponding to an input data sample in respective coordinate directions, the picture elements of a reproduction of the image being arranged in rows in each respective coordinate direction, said filter comprising

a filter circuit responsive to successive video input data samples corresponding to picture elements succeeding one another in rows in a given coordinate direction for producing respective filtered data samples corresponding to picture elements of a fractional-size reproduction of the image,

means for recursively applying the respective filtered data samples to said filter circuit a predetermined number of times to produce sequences of filtered data samples corresponding to respective fractional-size reproductions each related to its predecessor by a fixed reduction fraction along a given single coordinate direction, and

output means for successively outputting data samples corresponding respectively to the image and successive fractional-size reproductions thereof.

11. A memory system for sequentially storing data samples corresponding to picture elements of a video image arranged in rows in vertical and horizontal directions and for retrieving stored data samples corresponding to respective picture elements in a sequence different from that in which they were stored, said memory system comprising

a plurality of data storage modules for receiving data samples, each module having an addressable array of a plurality of storage cells into which cells a respective plurality of received data samples may be written for storage and from which stored data samples may be read for retrieval when the respective modules are addressed;

and

an addressing system coupled to address said modules according to either of first and second sequences,

said first sequence operating to store data samples in respective modules according to the sequence of respective picture elements in rows in one of said vertical and horizontal directions, in which first sequence the respective modules are addressed cyclically once only each cycle according to a first pattern for storing data samples in all respective modules each cycle with a plurality of cycles in respect to each image,

said second sequence operating to retrieve data samples from respective modules according to the sequence of respective picture elements in rows in the other of said vertical and horizontal directions, in which stored sequence the respective modules are addressed cyclically once only each cycle according to a second pattern for retrieving data samples from all respective modules each cycle with a plurality of cycles in respect to each image, and

said first sequence being related to said second sequence whereby the addressing of the modules according to said first pattern stores the data samples in different respective modules over a cycle of said second pattern.

12. A memory system for sequentially storing and retrieving data samples corresponding to picture elements of a two dimensional video image arranged in rows in vertical and horizontal directions where such data samples can be stored in sequential order at a data sample rate higher than the maximum access rate of individual data storage modules included in the memory system and can be retrieved in sequential order corresponding to either of said vertical and horizontal directions at a rate higher than the maximum access rate of said data storage modules, said memory system comprising

N data storage modules for receiving data samples, each module having a plurality of addressable storage locations and an access time greater than the time T between consecutive received data samples, N being an integer greater than 1 and T being the inverse of the data sample rate;

and

means for storing the received data samples in the N modules in such sequence that, within any span of N consecutive data samples corresponding to consecutive picture elements in any row in either of the vertical and horizontal directions, each data sample is stored in an addressable storage location in a unique storage module.