The present invention is related to image processing, and more particularly, to an image processing method and an associated image processing circuit.
For the purpose of increasing a frame rate to obtain a better display effect, an interpolated frame between two frames may be generated. Motion vector(s) and related image contents may be generated by motion estimation and motion compensation (MEMC). The motion estimation may cause a halo effect when an object moves fast in the image, however. A common MEMC process for eliminating the halo effect has the following problems: a width of the halo is too large; edges of the halo are misaligned; and strength of halo reduction is too strong and thereby introduces edge flicker.
Thus, an objective of the present invention is to provide an image processing method, which can effectively alleviate the halo effect caused by an interpolated frame, to solve the problems of the related art.
In an embodiment of the present invention, an image processing method is disclosed. The image processing method comprises the following steps: receiving an image signal, wherein the image signal comprises a first frame and a second frame; determining edges of a foreground in the first frame and the second frame according to at least one motion vector of the first frame and the second frame; determining an edge of the foreground in an interpolated frame according to the edge of the foreground in the first frame and the edge of the foreground in the second frame; and directly using one or more motion vectors of a background adjacent to the foreground in the first frame or the second frame to serve as one or more motion vectors of an outer region of the edge of the foreground in the interpolated frame.
In another embodiment of the present invention, an image processing circuit is disclosed, which comprises a receiving circuit and a motion estimation and motion compensation (MEMC) circuit. In operations of the image processing circuit, the receiving circuit is configured to receive an image signal, wherein the image signal comprises a first frame and a second frame; the MEMC circuit is configured to determine edges of a foreground in the first frame and the second frame according to at least one motion vector of the first frame and the second frame, determine an edge of the foreground in an interpolated frame according to the edge of the foreground in the first frame and the edge of the foreground in the second frame, and directly use one or more motion vectors of a background adjacent to the foreground in the first frame or the second frame to serve as one or more motion vectors of an outer region of the edge of the foreground in the interpolated frame.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Regarding detailed operations of the image processing circuit 100, the receiving circuit 110 receives the image signal Din, where the image signal Din comprises a first frame T1 and a second frame t2 shown in
More specifically, the MEMC circuit 120 may determine edges of the foreground in the first frame T1 and the second frame T2 according to at least one motion vector of the first frame T1 and the second frame T2, such as the edge PA of the foreground in the first frame T1 and the edge PB of the foreground in the second frame T2 shown in
In another embodiment, the foreground further has edges PA′ and PB′ in the first frame T1 and the second frame T2, and the MEMC circuit 120 determines an edge PC′ of the foreground in the interpolated frame T_I according to an the edge PA′ of the foreground in the first frame T1 and the edge PB′ of the foreground in the second frame T2; for example, a center point of the edges PA′ and PB′ may be calculated to serve as the edge PC′. Then, since an outer region 220 of the edge PC′ of the foreground in the interpolated frame T_I and the background adjacent to the foreground in the second frame T2 correspond to a same location (a same pixel location), the MEMC circuit 120 directly uses motion vector(s) of the background at the right-side of the foreground in the second frame T2 to serve as motion vector(s) of the outer region 220 of the edge PC′ of the foreground in the interpolated frame T_I. For example, assuming that a background region of the second frame T2 that is directly below the outer region 220 of the edge PC′ of the foreground in the interpolated frame T_I has a motion vector MV2 (i.e. a movement amount of a block of the background region relative to a reference frame or the first frame T1), the motion vector(s) of the region 220 may be directly modified as MV2 (i.e. the movement amount of the block relative to the reference frame or the first frame T1).
As mentioned above, since the motion vector(s) of the outer region 210 of the edge PC and the outer region 220 of the edge PC′ of the foreground in the interpolated frame T_I are directly modified as the motion vector(s) of the background of the first frame T1 or the second frame T2, the halo effect can be effectively reduced.
Step 300: the flow starts.
Step 302: receive an image signal, where the image signal comprises a first frame and a second frame.
Step 304: determine edges of a foreground in the first frame and the second frame according to at least one motion vector of the first frame and the second frame.
Step 306: determine an edge of the foreground in an interpolated frame according to the edge of the foreground in the first frame and the edge of the foreground in the second frame.
Step 308: directly use one or more motion vectors of a background adjacent to the foreground in the first frame or the second frame to serve as one or more motion vectors of an outer region of the edge of the foreground in the interpolated frame.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
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