Method and apparatus for encoding and decoding based on intra prediction

1. A method of encoding an image based on intra prediction, the method comprising:

determining an intra prediction direction of each unit block included in a current block;

dividing the current block into a plurality of sub blocks so that a plurality of unit blocks adjacent to each other are included in one of the sub blocks based on the intra prediction direction of each of the unit blocks included in the current block; and

performing intra prediction encoding on each of the sub blocks so that only one intra prediction direction is encoded in each of the sub blocks,

wherein unit blocks having equal intra prediction directions are bound as one sub block.

2. The method of claim 1 , wherein the sub blocks comprise sub blocks having a plurality of sizes or rectangular sub blocks of equal size.

3. The method of claim 2 , wherein the sub blocks having a plurality of sizes comprise rectangular sub blocks.

4. The method of claim 2 , wherein the rectangular sub blocks comprise at least one of blocks in 16×8, 8×16, 8×4, and 4×8 sizes.

5. The method of claim 2 , wherein the sub blocks having a plurality of sizes comprise square sub blocks.

6. The method of claim 5 , wherein the square sub blocks comprise at least one of blocks in 8×8 and 4×4 sizes.

7. The method of claim 2 , wherein the rectangular sub blocks comprise at least one of blocks in 16×8, 8×16, 8×4, and 4×8 sizes.

8. An apparatus for encoding an image based on intra prediction, the apparatus comprising:

an area divider which determines an intra prediction direction of each unit block included in a current block and divides the current block into a plurality of sub blocks so that a plurality of unit blocks adjacent to each other are included in one of the sub blocks based on the intra prediction direction of each of the unit blocks included in the current block; and

an intra prediction performer which performs intra prediction encoding on each of the sub blocks so that only one intra prediction direction is encoded in each of the sub blocks,

wherein unit blocks having equal intra prediction directions are bound as one sub block.

9. The apparatus of claim 8 , wherein the sub blocks comprise sub blocks having a plurality of sizes or rectangular sub blocks in one size.

10. The apparatus of claim 9 , wherein the sub blocks having a plurality of sizes comprise rectangular sub blocks.

11. The apparatus of claim 10 , wherein the rectangular sub blocks comprise at least one of blocks in 16×8, 8×16, 8×4, and 4×8 sizes.

12. The apparatus of claim 9 , wherein the sub blocks having a plurality of sizes comprise square sub blocks.

13. The apparatus of claim 12 , wherein the square sub blocks comprise at least one of blocks in 8×8 and 4×4 sizes.

14. The apparatus of claim 9 , wherein the rectangular sub blocks comprise at least one of blocks in 16×8, 8×16, 8×4, and 4×8 sizes.

15. A method of decoding an image based on intra prediction, the method comprising:

receiving a bit stream comprising data about a current block which is intra prediction encoded after determining an intra prediction direction of each unit block included in the current block and being divided into a plurality of sub blocks so that a plurality of unit blocks adjacent to each other are included in one of the sub blocks based on the intra prediction direction of the unit blocks included in the current block, and determining an intra prediction mode of the current block by referring to one intra prediction direction decoded from each of the plurality of sub blocks; and

intra prediction decoding the data about the current block in a unit of the sub blocks according to the determined intra prediction mode,

wherein unit blocks having equal a prediction directions are bound s one sub block.

16. The method of claim 15 , wherein the sub blocks comprise sub blocks having a plurality of sizes or rectangular sub blocks of equal size.

17. The method of claim 16 , wherein the sub blocks having a plurality of sizes comprise rectangular sub blocks.

18. The method of claim 16 , wherein the sub blocks having a plurality of sizes comprise square sub blocks.

19. The method of claim 16 , wherein the rectangular sub blocks comprise at least one of blocks in 16×8, 8×16, 8×4, and 4×8 sizes.

20. An apparatus for decoding an image based on intra prediction, the apparatus comprising:

an intra prediction mode determiner which receives a bit stream comprising data about a current block which is intra prediction encoded after determining an intra prediction direction of each unit block included in the current block and being divided into a plurality of sub blocks so that a plurality of unit blocks adjacent to each other are included in one of the sub blocks based on the intra prediction direction of the unit blocks included in the current block, and determines an intra prediction mode of the current block by referring to one intra prediction direction decoded from each of the plurality of sub blocks; and

an intra prediction performer which intra prediction decodes the data about the current block in a unit of the sub blocks according to the determined intra prediction mode,

wherein unit blocks having equal intra prediction directions are bound as one sub block.

21. The apparatus of claim 20 , wherein the sub blocks comprise sub blocks having a plurality of sizes or rectangular sub blocks of equal size.

22. The apparatus of claim 20 , wherein the sub blocks having a plurality of sizes comprise rectangular sub blocks.

23. The apparatus of claim 21 , wherein the sub blocks having a plurality of sizes comprise square sub blocks.

24. The apparatus of claim 21 , wherein the rectangular sub blocks comprise at least one of blocks in 16×8, 8×16, 8×4, and 4×8 sizes.

25. A non-transitory computer readable recording medium having recorded thereon a program for executing the method of claim 15 .