Image processing apparatus and method for controlling the same

1. An image processing apparatus that performs filtering by reading out an image from an external storage unit, the image being divided into a plurality of banks by a first interleave method according to a transfer length when the image is read out from the external storage unit, the apparatus comprising:

a plurality of local memories; and

a control unit configured to divide, into a plurality of pixel fragments, a pixel of a bank which includes at least one of a plurality of pixels needed for the filtering by a second interleave method according to the transfer length and store each of the pixel fragments obtained as a result of division in one of the plurality of local memories in accordance with the transfer length.

2. The apparatus according to claim 1 , wherein the external storage unit stores an image before one of deformation and rotation, and

the image processing apparatus reads out the image before one of deformation and rotation from the external storage unit to perform filtering, and generates an image after one of deformation and rotation.

3. The apparatus according to claim 2 , wherein the transfer length is set in accordance with a degree of one of deformation and rotation.

4. The apparatus according to claim 1 , wherein the first interleave method and the second interleave method are implemented by calculating a bank number bk and a local memory number lm by:

bk=[ ( m % 2)* B/ 2+ n] % B

lm=[ ( bk % 2)* L/ 2+beat] % L

where m is a main scanning coordinate of the transfer length, n is a sub scanning coordinate of the transfer length, B is the number of banks, beat is a packet number, and L is the number of local memories.

5. The apparatus according to claim 1 , wherein a size of each of the pixel fragments is set in accordance with a bus width of a bus configured to connect the external storage unit and the control unit.

6. The apparatus according to claim 1 , wherein a size of each of the pixel fragments is set in accordance with the number of pixels needed for the filtering.

7. The apparatus according to claim 1 , wherein at time when the plurality of pixels are read out from the plurality of local memories, and the plurality of pixels needed for the filtering cross a boundary of the pixel fragments, the control unit converts one request from a corresponding bank into two requests to two local memories.

8. The apparatus according to claim 1 , wherein the control unit rearranges pixels of the banks obtained as a result of division by the first interleave method into the pixel fragments of the second interleave method in accordance with bit lengths of the local memories and stores the pixel fragments in the local memories.

9. The apparatus according to claim 1 , wherein the control unit sequentially holds pixels of the banks obtained as a result of division by the first interleave method and writes the plurality of pixel fragments in the plurality of local memories concurrently.

10. The apparatus according to claim 1 , wherein the transfer length is set based on an image format.

11. The apparatus according to claim 1 , wherein the transfer length is set based on an access latency.

12. The apparatus according to claim 1 , wherein the number of banks in the first interleave method is set based on an image format and a pixel interpolation format of the filtering.

13. The apparatus according to claim 1 , wherein a plurality of images undergo one of different deformation operations and rotation operations so as to have the same shape, and are combined.

14. The apparatus according to claim 1 , further comprising a plurality of cache units corresponding to the plurality of banks,

wherein the plurality of cache units share the plurality of local memories, and

cache memories of the cache units are allocated to the plurality of local memories based on the transfer length.

15. The apparatus according to claim 14 , wherein an input image and an output image divided into areas are allocated to an area obtained by excluding areas of the cache memories from areas of the plurality of local memories.

16. An image processing apparatus, comprising:

a readout unit configured to read out pixel data of an image associated with a plurality of banks by a first interleave method according to a transfer length when the pixel data is read out from an external storage unit;

a plurality of local memories;

a control unit configured to perform control for dividing a plurality of pixel data of a first unit associated with the banks into a plurality of pixel data of a second unit by a second interleave method in accordance with the number of local memories, and

for storing a plurality of pixel data corresponding to the banks sequentially in the plurality of local memories so that local memories with which the storing in the second unit is started are different among banks which have been consecutively read out; and

a filtering unit configured to perform filtering by using a pixel data group of pixels read out from the plurality of local memories and adjacent in the image.

17. A method for controlling an image processing apparatus that performs filtering by reading out an image from an external storage unit, the image being divided into a plurality of banks by a first interleave method according to a transfer length when the image is read out from the external storage unit, and the image processing apparatus including a plurality of local memories, the method comprising:

dividing, into a plurality of pixel fragments, a pixel of a bank which includes at least one of a plurality of pixels needed for the filtering by a second interleave method according to the transfer length and storing each of the pixel fragments obtained as a result of division in one of the plurality of local memories in accordance with the transfer length.