# US 7,609,325 B2 · Apparatus and method for calculating source image coordinates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,325 B2 - Document ID: US7609325B2 - Status: Granted - Kind: B2 - Application number: 11/274,987 - Filed: 2005-11-15 - Published: 2006-05-18 - Granted: 2009-10-27 - Earliest claimed: 2004-11-15 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Seok-Jun Park; Gwang-Sun Lee; Yong-In Han; Jung-Tae Kim - Web page: https://patentgrep.com/patent/US7609325B2 ## CPC - H04N 5/2628: {Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation} - H04N 7/0122: {the input and the output signals having different aspect ratios} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method and an apparatus for calculating source image coordinates. In an embodiment, a variation rate of the source image coordinate with respect to a converted image coordinate is calculated by a recursive computation, and variation rates are accumulated to obtain the source image coordinate. Because the converted image coordinate sequentially increases one-by-one, the variation rate may be obtained by using adding operations of previously obtained source image coordinate, rather than multiplying operations with the all of the converted image coordinates. Therefore, the source image coordinates may simply and effectively be calculated. ## Claims ### Claim 1 A method of calculating source image coordinates comprising: calculating, by a polynomial calculator, a value of an (N−1)-th order differential polynomial corresponding to a converted image coordinate n, by a recursive computation; and calculating, by an accumulator, the source image coordinate xn corresponding to the converted image coordinate n by using the value of the (N−1)-th order differential polynomial corresponding to the converted image coordinate n and the previous source image coordinate xn−1 corresponding to a previous converted image coordinate n−1, wherein the (N−1)-th order differential polynomial is differentiated from an N-th order polynomial x(n) with respect to the converted image coordinate n, the N-th order polynomial x(n) representing the source image coordinates xn with respect to the converted image coordinate n, and N denoting a natural number larger than 2, and wherein a second order differential polynomial is the same as the (N−1)-th order differential polynomial when N=3. ### Claim 2 (depends on 1) The method of claim 1, wherein N is equal to 3. ### Claim 3 (depends on 1) The method of claim 1, wherein the method is used for a screen conversion with a panoramic function. ### Claim 4 (depends on 1) The method of claim 1, wherein the calculating the value, by the polynomial calculator, of an (N−1)-th order differential polynomial by the recursive computation uses the following expressions 1 and 2 recursively to obtain a second order term of the (N−1)-th order differential polynomial, An2=A(n−1)2+2A(n−1)=A 2An=2A(n−1)+2A wherein A denotes a second order coefficient of the second order differential polynomial. ### Claim 5 (depends on 4) The method of claim 4, wherein calculating, by the polynomial calculator, the value of the (N−1)-th order differential polynomial uses the following expression 3 recursively to obtain a first order term of the second order differential polynomial, Bn=B(n−1)+B, wherein B is a first order coefficient of the second order differential polynomial. ### Claim 6 (depends on 1) The method of claim 1, wherein calculating, by the polynomial calculator, the value of then (N−1)-th order differential polynomial comprises: maintaining constant the value of the second order differential polynomial, when the converted image coordinates n are located in a central portion of a converted image; and calculating the value of the second order differential polynomial by the recursive computation, when the converted image coordinates n are located at sides of the converted image. ### Claim 7 (depends on 1) The method of claim 1, wherein calculating the source image coordinate xn comprises adding the value of the second order differential polynomial corresponding to the converted image coordinate n and the previous source image coordinate xn−1 corresponding to the previous converted image coordinate n−1. ### Claim 8 (depends on 1) The method of claim 1, wherein the method is used for a screen conversion with a waterglass function. ### Claim 9 An apparatus for calculating source image coordinates, the apparatus comprising: a polynomial calculator configured to obtain a value of an (N−1)-th order differential polynomial corresponding to a converted image coordinate n, by a recursive computation; an accumulator configured to generate the source image coordinate xn by accumulating the value of the (N−1)-th order differential polynomial provided from the polynomial calculator; and a controller configured to control the polynomial calculator and the accumulator, wherein the (N−1)-th order differential polynomial is differentiated from an N-th order polynomial x(n) with respect to the converted image coordinate n, the N-th order polynomial x(n) representing the source image coordinates xn with respect to the converted image coordinate n, and N denoting a natural number larger than 2, and wherein a second order differential polynomial is the same as the (N−1)-th order differential polynomial when N=3. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein N is equal to 3. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein the apparatus is used for a screen conversion with a panoramic function. ### Claim 12 (depends on 9) The apparatus of claim 9, wherein the polynomial calculator uses the following expressions 1 and 2 recursively to obtain a second order term of the (N−1)-th order differential polynomial, An2=A(n−1)2+2A(n−1)+A 2An=2A(n−1)+2A, wherein A denotes a second order coefficient of the second order differential polynomial. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the polynomial calculator uses the following expression 3 recursively to obtain a first order term of the second order differential polynomial, Bn=B(n−1)+B, wherein B is a first order coefficient of the second order differential polynomial. ### Claim 14 (depends on 9) The apparatus of claim 9, wherein the accumulator outputs the source image coordinate xn by adding the value of the second order differential polynomial corresponding to the converted image coordinate n and the previous source image coordinate xn−1 corresponding to the previous converted image coordinate n−1. ### Claim 15 (depends on 9) The apparatus of claim 9, wherein the controller initializes the polynomial calculator and the accumulator with a given initial value, and the controller generates first and second control signals to respectively control the polynomial calculator and the accumulator so that the polynomial calculator and the accumulator respectively operate based on the converted image coordinate n. ### Claim 16 (depends on 9) The apparatus of claim 9, wherein when the converted image coordinates n are located in a central portion of the converted screen, the polynomial calculator maintains constant the value of the second order differential polynomial, and when the converted image coordinates are located at sides of the converted screen, the polynomial calculator calculates the value of the second order differential polynomial by the recursive computation. ### Claim 17 (depends on 9) The apparatus of claim 9, wherein the polynomial calculator comprises: a second order term calculator configured to obtain a second order term An2 of the second order differential polynomial; a first order term calculator configured to obtain a first order term Bn of the second order differential polynomial; and a summing part for summing the second order term, the first order term, and a constant term C of the second order differential polynomial. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein the second order term calculator comprises: a first flip-flop configured to store the second order term An2 corresponding to the converted image coordinate n, and to output the second order term An2 based on a first control signal; a second flip-flop configured to store a data 2A(n−1) corresponding to the converted image coordinate n, and to output the data 2A(n−1), based on the first control signal; a first adder for adding an output A(n−1)2 of the first flip-flop and the data 2A(n−1) of the second flip-flop and a second order coefficient A of the second order differential polynomial to output An=A(n−1)+2A(n−1)+A of the first adder to the first flip-flop; a second adder for adding the second order coefficient A to the second order coefficient A; and a third adder for adding an output 2A of the second adder and the output 2A(n−2) of the second flip-flop corresponding to the previous converted image coordinate n−1 to output an output 2A(n−1) of the third adder to the second flip-flop. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the first order term calculator comprises: a third flip-flop configured to store a first order term Bn and to output the first order term Bn of the second order differential polynomial, based on the first control signal; and a fourth adder for adding an output B(n−1) of the third flip-flop corresponding to the previous converted image coordinate n−1and a first coefficient B of the second order differential polynomial to output Bn of the fourth adder to the third flip-flop, based on the first control signal. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the summing part comprises a fifth adder for adding the second order term An2, the first order term Bn, and the constant term C. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the accumulator comprises: a fourth flip-flop for storing the source image coordinate xn; and a sixth adder for adding an output xn−1 of the fourth flip-flop corresponding to the previous converted image coordinate n−1 and the output An2+Bn+C of polynomial calculator to output the source image coordinate xn of the sixth adder to the fourth flip-flop. ### Claim 22 (depends on 9) The apparatus of claim 9, wherein the apparatus is used for a screen conversion with a waterglass function.