Image motion detection device

An image motion detection device for detecting motion in an image divided into n groups of blocks, each having classified attributes different from each other, comprising:

• a first motion detection section for generating a first motion vector by performing a first motion vector search for a group of blocks included in an image;
• a search information calculation section for calculating search information by using the first motion vector;
• second through n.sup.th motion detection sections for generating at least one of a second motion vector through an n.sup.th motion vector by performing one of a second motion vector search through an n.sup.th motion vector search for n groups of blocks other than the group of blocks upon which the search information is based, the second through n.sup.th motion vector searches being respectively different from the first motion vector search;
• and
• a motion vector selection section for selectively outputting at least one of the first through n.sup.th motion vectors,
• wherein a second through n.sup.th number of candidates for each of the second through n.sup.th motion vectors in the second through n.sup.th motion vector searches is smaller than a first number of candidates for the first motion vector in the first motion vector search.

A method for detecting motion in an image, comprising the steps of:

• dividing the image into at least a first block having a first classified attribute and a second block having a second classified attribute different from the first classified attribute;
• generating a first motion vector by performing a first motion vector search for the first block;
• calculating search information using the first motion vector;
• selecting candidates to be considered during a second motion vector search for the second block in accordance with the search information;
• and
• generating a second motion vector by performing the second motion vector search for the second block using candidates output by said selecting step.

A method for detecting motion in an image, comprising the steps of:

• dividing the image into n groups of blocks, each having classified attributes different from each other;
• generating a first motion vector by performing a first motion vector search for a group of blocks;
• calculating search information using the first motion vector;
• selecting candidates to be considered in each of a second through n.sup.th motion vector search in accordance with the search information;
• and
• generating at least one of a second through n.sup.th motion vector by performing at least one of the second motion vector search through the n.sup.th motion vector search for n groups of blocks other than the group of blocks upon which the search information is based, using candidates output by said selecting step.