Two-dimensional digital linear interpolation system

• US 4,402,012 A
• Filed: 11/16/1981
• Issued: 08/30/1983
• Est. Priority Date: 11/16/1981
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Knight, Wesley W.
• Primary Examiner(s): Martin, John C.
• Application Number:
  US06/321,890
• Time in Patent Office: 652 Days
• Field of Search: 358/11, 358/22, 358/138, 358/140, 358/160, 358/180, 358/260, 358/166, 365/515, 365/723, 365/853
• US Class Current: 348/580
• CPC Class Codes: G06F 17/175 of multidimensional data
• 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
• CPC Class Codes: H04N 1/40068 Modification of image resolution, i.e. determining the values of picture elements at new relative positions H04N1/3935 takes precedence

Abstract

A two-dimensional interpolation of image data is provided for a video display system, in which a one-dimensional interpolator performs the interpolation in both dimensions with data flow control so that images can be transmitted, scaled and displayed in real time.

Claims

1. A two-dimensional digital interpolation system comprising:

A. one-dimensional linear interpolator means for providing interpolated data values between pairs of input data values to generate primary interpolated scan lines for a video image; and

B. means for providing selected output data values of said primary interpolated scan lines as input data to said one-dimensional linear interpolater means for interpolation in a dimension perpendicular to said primary interpolated scan lines to generate intermediate interpolated scan lines.

2. The invention of claim 1 further comprising:

A. means for inputting data to said one-dimensional interpolator means;

B. output means to selectively output data to a video display means; and

C. control means for supplying control signals to said one-dimensional interpolator means, said means for inputting data, said means for providing output data as input data to said one-dimensional interpolator means and said output means.

3. The invention of claim 2 wherein said means for providing selected output data values of said primary interpolated scan lines as input data comprises:

A. first and second line buffer means for storing output data values of alternate ones of said primary interpolated scan lines;

B. said first and second line buffer means supplying said primary scan line data for two primary scan lines simultaneously to said means for inputting data; and

supplying said primary scan line data one line at a time to said output means.

4. The invention of claim 3 wherein said data input means comprises:

A. memory means for storing image data to be interpolated and sequentially outputting said stored image data to be input to said one-dimensional interpolator means;

B. input register means for temporarily storing input data received as input from said memory means and controllably supplying said data as an input for said one-dimensional interpolator;

C. first input multiplexer means for receiving as a first input said data output by said input primary scan line data from said first line buffer means;

D. second input multiplexer means for receiving as a first input said data output by said memory means, and receiving as a second input primary scan line data from said second line buffer means; and

wherein

E. said control means includes means for controlling said first and second input multiplexer means to output simultaneously to said one-dimensional interpolator, said respective first inputs and to output simultaneously said respective second inputs.

5. The invention of claim 3 wherein said output means comprises:

A. an output multiplexer controlled by said control means to sequentially output interpolated primary line data from said first line buffer means, intermediate interplated line data from said one-dimensional interpolator means, and interpolated primary line data from said second line buffer means; and

wherein said control means comprises;

(1) a system clock for supplying clock pulse;

(2) a counter for receiving said clock pulses and outputting a series of synchronizing signals; and

(3) a programmable read only memory programmed to provide control signals to said one-dimensional interpolator means, said means for inputting data, said means for providing selected output data values of said primary interpolated scan line and said output data.

6. The invention of claim 5 wherein said one-dimensional interpolator comprises:

A. third and fourth output multiplexer means for receiving said interpolator input signals and outputting selected ones of said input signals, said control means including means to control the respective outputs of said third and fourth input multiplexers to sequence said one-dimensional interpolator through a sequence of interpolator states to provide linear interpolation data between said input data values;

B. a first summer having as a first summer input the output from said fourth input multiplexer means and having as a second summer input said output from said second input multiplexer means and providing as a first summer output the sum of said first and second input signals; and

C. a second summer having as inputs the output from said third input multiplexer means and said first summer output and providing as a second summer output the sum of said third and fourth summer input signals.

7. A method for two-dimensional linear interpolation of a video image comprising the steps of:

(a) performing a linear interpolation of successive lines of video image data in a first dimension using a one-dimensional linear interpolator to produce successive linearly interpolated primary scan lines; and

(b) performing a linear interpolation between said successive interpolated primary scan lines in a second dimension perpendicular to said first dimension using the same said one-dimensional linear interpolator to produce intermediate scan lines for said video image.

8. The method of claim 7 wherein step (a) comprises the steps of:

(1) inputting line data for a first image line from a memory means in which image line data has been stored to said one-dimensional linear interpolator;

(2) linearly interpolating said line data for said first image line to provide a first interpolated primary scan line;

(3) electronically storing said first interpolated primary scan line;

(4) inputting line data for a second image line from said memory means to said one-dimensional linear interpolator;

(5) linearly interpolating said line data for said second image line to provide a second interpolated primary scan line; and

(6) electronically storing said second interpolated primary scan line.

9. The method of claim 8 wherein step (b) comprises the steps of:

(1) inputting said first and second interpolated primary scan line to said one-dimensional linear interpolator;

(2) linearly interpolating between corresponding data points of said first and second interpolated primary scan lines to provide intermediate interpolated scan lines.

10. The method of claim 9 further comprising the steps of:

(1) outputting said first interpolated primary scan line as a display input signal;

(2) outputting sequentially said intermediate interpolated scan lines as display input signals; and

(3) outputting said second interpolated primary scan line as a display input signal.

11. The method of claim 10 further comprising:

(1) successively providing interpolated primary scan lines and interpolated intermediate scan lines;

(2) outputting an interpolated primary scan line to a video display simultaneous with the interpolation of the next successive primary scan line;

(3) outputting said intermediate scan lines immediately as they are outputted by said interpolator means; and

(4) succssively repeating steps (2) and (3) of this claim until the complete video image has been interpolated and displayed.