one
产生右图所示图像f1(m,n)，其中图像大小为256×256，中间亮条为128
×32，暗处=0，亮处=100。对其进行FFT：
① 同屏显示原图f1(m,n)和FFT(f1)的幅度谱图；
② 若令f2(m,n)=（-1）m+n f1(m,n)，重复以上过程，比较二者幅度
谱的异同，简述理由；
③ 若将f2(m,n)顺时针旋转90 度得到f3(m,n)，试显示FFT(f3)的幅
度谱，并与FFT(f2)的幅度谱进行比较；
④ 若将f1(m,n) 顺时针旋转90 度得到f4(m,n)，令f5(m,n)=f1(m,n)+f4(m,n)，试显
示FFT(f5)的幅度谱，并指出其与FFT(f1)和FFT(f4)的关系；
⑤ 若令f6(m,n)=f2(m,n)+f3(m,n)，试显示FFT(f6)的幅度谱，并指出其与FFT(f2)和
FFT(f3)的关系，比较FFT(f6)和FFT(f5)的幅度谱。(Generating an image f1 (m, n) shown in the figure, wherein the image size is 256 256, the intermediate light bar 128 32 0 = dark, bright Department 100. Its FFT: ① screen display picture f1 (m, n) and the FFT (f1) of the amplitude spectrum ② If so f2 (m, n) = (-1) m+n f1 (m, n), repeat The above process, comparing the amplitude spectrum of the similarities and differences between the two, brief reasons ③ If f2 (m, n) 90 degrees clockwise to get f3 (m, n), try to display FFT (f3) the amplitude spectrum and with the FFT (f2) comparing the amplitude spectrum ④ If f1 (m, n) obtained by 90 degrees clockwise f4 (m, n), so f5 (m, n) = f1 (m, n)+f4 (m, n ), try to display FFT (f5) amplitude spectrum, and pointed out its relationship with the FFT (f1) and FFT (f4) of ⑤ If so f6 (m, n) = f2 (m, n)+f3 (m, n) and try to display the FFT (f6) amplitude spectrum, and pointed out its relationship with the FFT (f2) and FFT (f3), comparing FFT (f6) and FFT (f5) amplitude spectrum.)
- 2013-11-26 16:24:18下载
- 积分：1
PrProcessing
在进行车牌识别的预处理过程中,如何有效地提高车牌图像质量是一个关键,这一步处理的好坏将直接影响到后面车牌识别的效果。 本文重点研究直方图修改技术增强图像方法在车牌识别预处理中的应用,给出了直方图修改技术的原理,以及直方图均衡化、规定化和对比度调整的原理,最后用MATLAB来实现车牌图像增强的效果。(License Plate Recognition in the pre-treatment process, how to effectively improve the image quality license plate is a key to dealing with the merits or demerits of this step will directly affect the effectiveness of the back license plate recognition. This article focuses on the image histogram modification method to enhance license plate recognition in the pre-processing of applications, given the principle of histogram modification techniques, as well as histogram equalization, contrast adjustment provisions and the principles of using MATLAB to achieve the final vehicle the effect of brand image enhancement.)
- 2009-04-22 22:02:17下载
- 积分：1
