1. A processor-implemented method for motion estimation, the method comprising: receiving, by a processor, a sequence of pixel events, generated asynchronously by an event-based video camera; receiving, by the processor, a sequence of image frames generated by a frame-based video camera at a frame sampling period; integrating, by the processor, a subset of the sequence of pixel events, occurring within the frame sampling period between two of the image frames, to generate a pixel motion vector representing motion of the pixel between the two image frames; and mapping, by the processor, the pixel motion vector to a tile of one of the image frames to generate an estimated motion vector associated with the tile.