Fast seam carving based on direction map

Seam carving is a new image retargeting method, which can alleviate the distortion on the main content of the image compared to the traditional scaling method. However, the original seam carving method uses the gradient amplitudes of pixels to construct the energy map, but neglects the gradient directions of pixels. Actually, the gradient direction refers to the direction where the pixel has the maximum rate of change. We can use the gradient direction of pixels to construct the direction map, and then naturally generate multiple seams from top to bottom based on the direction map. In addition, we use the priority windows to avoid intersecting seams. Experimental results show that our method can accelerate the speed of seam carving about 98 times while maintaining the quality of the image retargeting result.