基于FPGA的高速高质量图像旋转

为了进行高质量、高速的图像旋转变换 ,通过对传统图像旋转矩阵的分解 ,将图像在二维空间中的旋转运算分解成为三次一维空间内的平移运算 ,从而将用于图像旋转运算的二维插值运算简化为在一维空间中进行的一维插值运算。为了保证图像旋转后的质量 ,采用 3阶 B-样条对每次平移后像素点的灰度值进行插值运算 ,并提出了一种基于 IIR和 FIR数字滤波器的 3阶 B-样条插值法的高速实现方案 ;最后针对 2 5 6灰度级 ,2 5 6× 2 5 6像素的图像设计出一种基于 FPGA的高速、高质量的硬件图像旋转及显示系统

FPGA-based Fast and High-quality Rotation of Image

In order to realize fast and high-quality rotation transform for image , this paper introduces the approach of decomposition of a two-dimensional rotation into three-step one-dimensional shift by decomposing the traditional matrix of image rotation, which succeeds in simplifying the interpolation of image in one-dimensional space. In order to ensure high quality of rotated image, the paper uses the cubic B-spline interpolation to calculate the gray of pixels after each image shift. What is more, the paper develops an IIR(infinite impulse response)-based and a FIR(finite impulse response)-based digital filter to realize fast cubic B-spline interpolation, which turns out to be a significant advantage for hardware implementation and parallelization. And it designs a FPGA(field programmable gate array)-based fast and high quality image rotation system for the 256×256 pixels images in 256 gray levels. By the means of coordinates transforming, the calculation time and storage will not increase evidently when the images rotate at a large angle in the system. In a word, the image rotation system is able to meet the request of real-time and high-quality rotation of image at any angle.