Apparatus and method for digital image stabilization

An apparatus for compensating a jitter occurred in the ith frame among N frames of a video sequence, each of the N frames comprising a plurality of blocks, N being a natural number larger than 2, and i being an integer index ranging from 1 to N, said apparatus comprising:

• a determining module for determining a block of background region BRi-1 in the (i−1)th frame;
• a comparing module, coupled to the determining module, for comparing the block of BRi-1 in the (i−1)th frame with the corresponding block in the ith frame to determine a jitter vector;
• and
• an adjusting module, coupled to the comparing module, for adjusting the ith frame in accordance with the jitter vector to compensate for the jitter occurred in the ith frame;
• wherein the determining module comprises:
• a second processing module for determining a block in the (j−1)th frame, which corresponds to a block in the (j−2)th frame, to define a global motion vector and setting the block as a processing block in the (j−1)th frame, j being an integer index ranging from 3 to (i−1);
• a second access module, coupled to the second processing module, for accessing the processing block in the (j−1)th frame determined by the second processing module and identifying the block as a block of background region BRj-1 in the (j−1)th frame;
• a second computing module, coupled to the second access module, for calculating a jitter vector defined by the block of BRj-1 and the corresponding block in the jth frame;
• and
• a second judgment module, coupled to the second computing module, for judging if the jitter vector computed by the second computing module lies within a range and, if YES, adjusting the jth frame in accordance with the jitter vector.

A method for compensating a jitter occurred in the ith frame among N frames of a video sequence, each of the N frames comprising a plurality of blocks, N being a natural number larger than 3, and i being an integer index ranging from 1 to N, said method comprising the steps of:

• (a) determining a block of background region BRi-1 in the (i−1)th frame;
• (b) comparing the block of BRi-1 determined in step (a) with the corresponding block in the ith frame to determine a jitter vector;
• and
• (c) adjusting the ith frame in accordance with the jitter vector to compensate for the jitter occurred in the ith frame;
• wherein step (a) further comprises the steps of:
• (a1) determining a block in the (j−2)th frame, which corresponds to a block in the (j−3)th frame, to define a global motion vector and setting the block as a processing block in the (j−2)th frame, j being an integer index ranging from 4 to (i−1);
• (a2) accessing the block in the (j−1)th frame which corresponds to the processing block in the (j−2)th frame determined in step (a1) and identifying the block as a block of background region BRj-1 in the (j−1)th frame;
• (a3) computing a jitter vector defined by the block of BRj-1 and the corresponding block in the jth frame;
• and
• (a4) if the jitter vector determined in step (a3) lies within a range, adjusting the jth frame in accordance with the jitter vector.

A method for compensating a jitter occurred in the ith frame among N frames of a video sequence, each of the N frames comprising a plurality of blocks, N being a natural number larger than 2, and i being an integer index ranging from 1 to N, said method comprising the steps of:

• (a) determining a block of background region BRi-1 in the (i−1)th frame;
• (b) comparing the block of BRi-1 determined in step (a) with the corresponding block in the ith frame to determine a jitter vector;
• and
• (c) adjusting the ith frame in accordance with the jitter vector to compensate for the jitter occurred in the ith frame;
• wherein step (a) further comprises the steps of:
• (a5) determining a block in the (j−1)th frame, which corresponds to a block in the (j−2)th frame, to define a global motion vector and setting the block as a processing block in the (j−1)th frame, j being an integer index ranging from 3 to (i−1);
• (a6) accessing the processing block in the (j−1)th frame determined in step (a5) and identifying the block as a block of background region BRj-1 in the (j−1)th frame;
• (a7) computing a jitter vector defined by the block of BRj-1 and the corresponding block in the jth frame;
• and
• (a8) if the jitter vector determined in step (a7) lies within a range, adjusting the jth frame in accordance with the jitter vector.