Claims
- 1. A read address generator for generating read addresses for a read memory comprising:
- first conversion means for converting input read addresses indicated using an orthogonal coordinate system into equivalent addresses in a polar coordinate system;
- means for dividing said polar coordinate system into blocks according to distances from the pole of said polar coordinate system, said blocks being concentric and having radial widths that are controlled on the basis of values obtained by adding random values to a reference value;
- vector setting means for setting vectors for said blocks, the angles of said blocks in said polar coordinate system sequentially increasing or decreasing;
- second conversion means for converting coordinate values indicated by said vectors into coordinate values in the orthogonal coordinate system; and
- means for generating output read addresses by subtracting said coordinate values from said input read addresses indicated in said orthogonal coordinate system and for supplying said output read addresses to said video memory.
- 2. The read address generator according to claim 1, wherein the size of the vectors for said blocks is fixed.
- 3. The read address generator according to claim 1, wherein the sizes of the vectors for said blocks are obtained by adding random values to a reference value.
- 4. The read address generator according to claim 1, wherein the angles of the vectors for said blocks vary at a fixed rate.
- 5. The read address generator according to claim 1, wherein the rate at which the angles of the vectors for said blocks vary is controlled on the basis of values obtained by adding random values to a reference value.
- 6. A method of generating read addresses for a video memory comprising the steps of:
- converting input read addresses indicated using an orthogonal coordinate system into equivalent addresses in a polar coordinate system;
- dividing said polar coordinate system into blocks according to distances from the pole of said polar coordinate system, said blocks being concentric and having radial widths that are controlled on the basis of values obtained by adding random values to a reference value;
- setting vectors for said blocks, the angles of said blocks in said polar coordinate system sequentially increasing or decreasing;
- converting coordinate values indicated by said vectors into coordinate values in the orthogonal coordinate system; and
- generating output read addresses by subtracting said coordinate values from said input read addresses indicated in said orthogonal coordinate system and for supplying said output read addresses to said video memory.
- 7. The read address generator according to claim 1, wherein the blocks are concentric and circular in shape.
- 8. The method of claim 6, wherein the blocks are concentric and circular in shape.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-112094 |
Apr 1993 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/226,936, filed Apr. 13, 1994, now abandoned
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4648049 |
Dines et al. |
Mar 1987 |
|
5051734 |
Lake, Jr. |
Sep 1991 |
|
5225824 |
Yamamoto et al. |
Jul 1993 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
0437074 |
Jul 1991 |
EPX |
2164520 |
Mar 1986 |
GBX |
Non-Patent Literature Citations (1)
Entry |
WPI Abstract Acc No: 93-023134/03 and JP 04 351078 A (NEC) see abstract. |
Continuations (1)
|
Number |
Date |
Country |
Parent |
226936 |
Apr 1994 |
|