CA1103345A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Digital scan converter
Assignee: Oki Electric Industry Co Ltd
•
Filing: 1978-08-10
•
Granted: 1981-06-16
•
Expires: 1998-08-10
Abstract
Abstract ABSTRACT OF THE DISCLOSURE There is disclosed a visual scan converter which accepts digitalized video data in a polar coordinates system from a source such as a radar receiver, a sonar, or an ultrasonic imaging system, and converts the data format to make it suitable for presentation on a cathode ray tube in a standard television or other orthogonal raster at flicker free rates. The input data in a polar coor-dinates system is first stored in a digital memory, which is read with the orthogonal coordinates system. In reading said digital memory, an orthogonal address generated by a raster address generator is converted to a polar address, which is applier to said digital memory. An interpolation is performed for the outputs of the digital memory.
Inventors
- 👤 Kazuhiko Nitadori
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-10-25 21:10
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/295; G01S7/298; G01S7/52; G01S7/52017; G01S7/52053; G01S7/52057; G01S7/5206; G01S7/523; G01S7/526; G01S7/53; G01S7/531
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
221 words
A digital scan converter for converting the coordinate system of a picture signal from a first coordinate system at the first rate to a second coordinate system at the second rate comprising; a) an input terminal for receiving a time sequential digital data at the first rate with the addresses of the first coordinate system, b) a digital memory for storing the digital data applied to the input terminal according to the first coordinate addresses, c) a synchronization signal generator, d) a raster address generator which generates the addresses in the second coordinate system synchronized with the output of said synchronization signal generator, e) a coordinate system converter for converting the second coordinate system from said raster address generator to the first coordinate system, f) an address generator for composing the addresses of said digital memory in the first coordinate system according to the output of said coordinate system converter, g) a fixed coefficient memory for storing a sampling function, h) an interpolation circuit connected to the outputs of said digital memory and said coefficient memory for carrying out the interpolation of the output of said digital memory, and i) an output terminal for providing the converted second coordinate image signal with the synchronization signal from said synchronization signal generator and the image signal from the output of said interpolation circuit.
Claim 2
Dependent Claim
221 words
A digital scan converter for converting the coordinate system of a picture signal from a first coordinate system at the first rate to a second coordinate system at the second rate comprising; a) an input terminal for receiving a time sequential digital data at the first rate with the addresses of the first coordinate system, b) a digital memory for storing the digital data applied to the input terminal according to the first coordinate addresses, c) a synchronization signal generator, d) a raster address generator which generates the addresses in the second coordinate system synchronized with the output of said synchronization signal generator, e) a coordinate system converter for converting the second coordinate system from said raster address generator to the first coordinate system, f) an address generator for composing the addresses of said digital memory in the first coordinate system according to the output of said coordinate system converter, g) a fixed coefficient memory for storing a sampling function, h) an interpolation circuit connected to the outputs of said digital memory and said coefficient memory for carrying out the interpolation of the output of said digital memory, and i) an output terminal for providing the converted second coordinate image signal with the synchronization signal from said synchronization signal generator and the image signal from the output of said interpolation circuit.
Claim 3
Dependent Claim
28 words
A digital scan converter according to claim 1 wherein the first coordinate system is a polar coordinate system and the second coordinate system is an orthogonal coordinate system.
Claim 4
Dependent Claim
42 words
A digital scan converter according to claim 2, wherein the coordinate system converter performs the calculation: where (x, y) are the orthogonal coordinates, (x0, y0) are the coordinates of the origin in the orthogonal coordinate system, and (r,.theta.) are the polar coordinates.
Claim 5
Dependent Claim
40 words
A digital scan converter according to claim 1, wherein the interpolation circuit comprises a multiplier for providing the product of the data of a lattice point and a weight defined by the sampling function, and means for accumulating said product.
Claim 6
Dependent Claim
25 words
A digital scan converter according to claim 1, wherein the input digital data is complex data, and the interpolation circuit performs a complex interpolation calculation.
Claim 7
Dependent Claim
35 words
A digital scan converter according to claim 1, further comprising a refresh memory connected to said output terminal for storing the output data at a slow rate and reading the same at a high rate.
Claim 8
Dependent Claim
40 words
A digital scan converter according to claim 3, wherein Q=X/Y is obtained from X=x-x0 and Y=y-y0, obtaining f(Q) = , and .theta.=cot-1 Q using the two function tables, and obtaining the value r as the product of f(Q) and Y.
Claim 9
Dependent Claim
55 words
A digital scan converter according to claim 7, wherein means for calculating Q=X/Y comprises a first register for storing (where xi is the initial value of x), a second register of storing .DELTA.x/Y (where .DELTA.x is the unit of x), and an adder for accumulating the content of the second register to the first register.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.