关键词: 仿射变换, 前置插值, 四角点映射, 现场可编程门阵列（FPGA）

Abstract:

The FPGA implementation of the affine transformation on the real-time video is mostly based on backward mapping, which derives the target image by bilinear interpolation of the four neighborhood pixels. However, the transmission of the four neighborhood pixels on the memory requires FPGA to provide the four times data bandwidth of the original image stream, resulting in the defects of high memory cost and low throughput. To solve this problem, the pre-interpolation based affine transformation is proposed in this paper. This method which adopts the four-corner mapping to construct the mapping function can perform bilinear interpolation before the image data flow is cached on the memory, so the four times data transmission bandwidthon the memory can be removed. Experiments on FPGA demonstrate that the proposed method has better overall performance in terms of throughput and memory cost compared to the affine transformation based on the backward mapping.

Key words: affine transformation, pre-interpolation, four-corner mapping, Field Programmable Gate Array（FPGA）