点评：一种基于可分级块的虚拟视点图像绘制方法，优点在于根据参考视点的深度图像的平滑与否自适应地将彩色图像划分成若干个尺寸大小不尽相同的块，对于整块映射型块只需对该块中的一个像素点实施三维图像变换以确定将该像素点从彩色图像投影到虚拟视点彩色图像的坐标映射关系，然后整个块采用此坐标映射关系投影到虚拟视点彩色图像中，由于只对一个像素点实施三维图像变换，因而可有效提高整块映射型块的绘制速度；对于逐像素映射型块，由于这些块主要位于对象与背景的边界区域，因此仍采用逐像素映射的三维图像变换方法将块中的各个像素点映射到虚拟视点彩色图像中，有效保证了绘制精度。

Comment: The invention discloses a gradable block-based virtual viewpoint image drawing method which is characterized by comprising the following steps: dividing a color image into a plurality of blocks with different sizes in a self-adapting way according to the smoothness of a depth image of a reference viewpoint; for a whole mapping type block, only needing to carry out three-dimensional image conversion on one pixel point in the block to determine the coordinate mapping relation for projecting the pixel point from the color image into a virtual viewpoint color image, and then, projecting the wholeblock into the virtual viewpoint color image by using the coordinate mapping relation, wherein because the three-dimensional image conversion is only carried out on one pixel point, the drawing speedof the whole mapping type block can be effectively improved; and for sequential pixel mapping type blocks, because the blocks are mainly positioned in the boundary regions of an object and a background, still mapping each pixel point in the blocks into the virtual viewpoint color image by using a sequential pixel mapping type three-dimensional image conversion method, thereby effectively ensuringthe drawing precision.