Interpolated frame generating method and interpolated frame generating apparatus

1. An interpolated frame generating method of generating a new interpolated frame inserted between sequential frames, by using a plurality of input frame images, comprising:

first detecting of detecting at least one potential motion vector by block matching processing between the input frame images, using a first block of a fixed size;

second detecting of detecting a motion vector by block matching processing between the input frame images, using a second block having a size which is variable within a range larger than that of the first block;

adaptively adjusting the size of the second block in accordance with a picture pattern of at least one of the input frame images;

generating the interpolated frame by using the potential motion vector when the number of the potential motion vector detected by the first detecting is one,

wherein, the generating is generating the interpolated frame by using a potential motion vector, which is closest to the motion vector detected by the second detecting among the potential motion vectors, when a plurality of motion vectors are detected by the first detecting.

2. The interpolated frame generating method according to claim 1 , wherein

the adjusting is adjusting the size of the second block to set the number of motion vectors detected by the second detecting to 1.

3. The interpolated frame generating method according to claim 2 , wherein

the adjusting is setting the size of the second block to a size N times as large as the size of the first block, where N is a natural number of 2 or more.

4. The interpolated frame generating method according to claim 1 , wherein

the adjusting includes:

measuring the number of successive occurrences of events, in which a plurality of potential motion vectors are detected by the first detecting, in said between the input frame images; and

calculating a width of a periodical repetitive pattern in said one of the input frame images based on a result of the measuring, and setting the size of the second block wider than the calculated width.

5. The interpolated frame generating method according to claim 1 , wherein

the adjusting includes:

measuring the number of repetitions of a unit pattern on a line of said one of the input frame images; and

calculating a width of a periodical repetitive pattern in said one of the input frame images based on a result of the measuring, and setting the size of the second block wider than the calculated width.

6. The interpolated frame generating method according to claim 1 , wherein

the first detecting includes:

calculating an absolute difference value between corresponding pixel values of image blocks in the input frame images; and

adopting a motion vector corresponding to a minimum value of a cumulative sum of the absolute difference values as the potential motion vector.

7. An interpolated frame generating apparatus which generates a new interpolated frame inserted between sequential frames, by using a plurality of input frame images, comprising:

a first detecting section configured to detect at least one potential motion vector by block matching processing between the input frame images, using a first block of a fixed size;

a second detecting section configured to detect a motion vector by block matching processing between the input frame images, using a second block having a size which is variable within a range larger than that of the first block;

an adjusting section configured to adaptively adjust the size of the second block in accordance with a picture pattern of at least one of the input frame images; and

a generating section configured to generate the interpolated frame by using the potential motion vector when the number of the potential motion vector detected by the first detecting section is one,

wherein, the generating section generates the interpolated frame by using a potential motion vector, which is closest to the motion vector detected by the second detecting section among the potential motion vectors, when a plurality of motion vectors are detected by the first detecting section.

8. The interpolated frame generating apparatus according to claim 7 , wherein

the adjusting section adjusts the size of the second block to set the number of motion vectors detected by the second detecting section to 1.

9. The interpolated frame generating apparatus according to claim 8 , wherein

the adjusting section sets the size of the second block to a size N times as large as the size of the first block, where N is a natural number of 2 or more.

10. The interpolated frame generating apparatus according to claim 7 , wherein

the adjusting section performs:

measuring the number of successive occurrences of events, in which a plurality of potential motion vectors are detected by the first detecting section, in said between the input frame images; and

calculating a width of a periodical repetitive pattern in said one of the input frame images based on a result of the measuring, and setting the size of the second block wider than the calculated width.

11. The interpolated frame generating apparatus according to claim 7 , wherein

the adjusting section performs:

measuring the number of repetitions of a unit pattern on a line of said one of the input frame images; and

calculating a width of a periodical repetitive pattern in said one of the input frame images based on a result of the measuring, and setting the size of the second block wider than the calculated width.

12. The interpolated frame generating apparatus according to claim 7 , wherein

the first detecting section includes:

a calculating section which calculates an absolute difference value between corresponding pixel values of image blocks in the input frame images; and

an adopting section which adopts a motion vector corresponding to a minimum value of a cumulative sum of the absolute difference values as the potential motion vector.