| 摘要 |
PURPOSE:To prevent malfunction due to an environmental change and to perform tracking operation with high precision regardless of the environmental change by providing a means which extends an update period as a stage in which a subject to be tacked is possibly at a substantial stop continues. CONSTITUTION:A movement decision circuit 114 compares values stored in a reference color memory 113 with a value extracted newly from each picture element. The period in which the storage contents of a storage means stored with tracked subject features are updated when a decision means 114 which decides on the movement of the subject according to the decision result is made longer and longer as the state in which the tracked subject is possibly at a substantial stop continues longer and longer. A reference value to replace is a value which is already calculated as the mean value of signals exetracted from respecetive picture elements in the last N-time extraction, so an extremely representative reference value is updated with little time loss without resetting the reference value by interrupting tracking operation for, for example, N/60 seconds. |
