Object tracking device
In an object tracking device, a search region setting unit sets the search region of an object in a frame image at a present point in time, based on an object region in a frame image at a previous point in time, zoom center coordinates in the frame image at the previous point in time, and a ratio between the zoom scaling factor of the frame image at the previous point in time and the zoom scaling factor of the frame image at the present point in time. A normalizing unit normalizes the image of a search region of the object included in the frame image at the present point in time to a fixed size. A matching unit searches the normalized mage of the search region for an object region similar to a template image.
1. An object tracking device that tracks an object included in a frame image, the object tracking device comprising:
a storage unit configured to store a template image of an object to be a track target;
an image input unit configured to receive a frame image in a time series;
a search region setting unit configured to set a search region of the object in a frame image at a present point in time, when a zoom scaling factor of the frame image at the present point in time is different from a zoom scaling factor of a frame image at a previous point in time, based on an object region in the frame image at the previous point in time, zoom center coordinates in the frame image at the previous point in time, and a ratio between the zoom scaling factor of the frame image at the previous point in time and the zoom scaling factor of the frame image at the present point in time;
a normalizing unit configured to normalize an image of the search region of the object included in the frame image at the present point in time to a fixed size; and
a matching unit configured to search the normalized image of the search region for an object region similar to the template image.
2. The object tracking device according to claim 1 ,
wherein the search region setting unit sets a region where a reference region including the object region in the frame image at the previous point in time and larger than the object region by a predetermined multiple is zoomed according to the zoom center coordinates and the ratio between the zoom scaling factors to the search region of the object in the frame image at the present point in time.
3. The object tracking device according to claim 1 , comprising:
a holding unit configured to hold the search region of the set object when a part of or the entire search region of the object set at the search region setting unit is not included in the frame image at the present point in time,
wherein after a point in time elapses, when the zoom scaling factor of the frame image at the present point in time is different from the zoom scaling factor of the frame image at the previous point in time, the search region setting unit uses the search region of the object held at the holding unit to set the search region of the object in the frame image at the present point in time.
4. The object tracking device according to claim 1 , further comprising:
a registration unit configured to store, in the storage unit as the template image, an image of a target object outputted from an object detector that detects a target object from a frame image.
5. The object tracking device according to claim 4 ,
wherein the registration unit updates the template image in the storage unit with an image of the object region at the present point in time searched at the matching unit as the image is similar to the template image.
6. The object tracking device according to claim 1 ,
wherein when a similar region is unable to be searched, the matching unit instructs the object detector to detect the object.