Description: 对girl图像做二维DCT，并通过对变换后的某些系数置零达到压缩目的-Girl doing two-dimensional images of the DCT, and through certain coefficients transformed to achieve compression purpose of nulling Platform: |
Size: 1024 |
Author:shirley |
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Description: 对“2.1.bmp”图像操作，将其放大至原来大小的1.5倍，采用双线性插值方法放大。
对“2.1.bmp”绕图像中心逆时针旋转20度，采用双线性插值方法。此题目不要使用imresize和imrotate函数，自己写程序完成。
2.对畸变图像进行矫正:”2.2.bmp”为畸变后的图像，已知畸变后图像上的四个点（118，88）（90，140）（139，168）（168，116）对应畸变前的点分别为为（98，98）（98，158）（158，158）（158，68），用对应点约束法求畸变前的图像。（题目中的坐标为行-列坐标；涉及到的插值用双线性插值法）
3.利用离散余弦变换函数（dct2和idct2）对“lena.bmp”做压缩，观察压缩效果。
-Image manipulation, "2.1.bmp" zoom to 1.5 times the original size, using bilinear interpolation method to enlarge.
"2.1.bmp" around the center of the image counterclockwise rotation of 20 degrees, a bilinear interpolation method. This topic Do not use imresize, and imrotate function, write your own program to complete.
2 of the distortion of the image to be corrected: "2.2.bmp" image after distortion, it is known that the four points on the image of the distortion (118,88) (90,140) (139,168) (168,116) corresponding to distortion prior to the point were to (98,98) (98,158) (158,158) (158,68), with a corresponding point constraint method seeking the image in front of the distortion. (Coordinates in the subject line- column coordinate involves interpolation with bilinear interpolation)
3 using discrete cosine transform the function (dct2, and idct2) "lena.bmp" do the compression, to observe the compression effect.
Platform: |
Size: 2048 |
Author:单车少年 |
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Description: （1）试利用函数dct2，对该图像进行压缩。压缩时可尝试对DCT 变换后的系数采用不同取舍方法，比较其压缩性能。（函数dct2在matlab本身是有的，可以help dct2看看）
（2）结合课本例8.7.2 的量化方法，对每一个经DCT变换后的8×8 矩阵量化（Huffman编码部分可省略），从而实现图像压缩。在一定压缩比的情况下，和⑴给出的图像质量相比较。
（3）用所给的子子程序fast_LOT.m 实现对该图像的变换与压缩，并和（1）得出的图像质量相比较-(1) Test using function dct2, the image is compressed. The compression can try to adopt different choices, the DCT transform coefficients after comparing its compression performance. (Function dct2 the matlab itself is some help dct2 see) (2) combined with the textbook cases 8.7.2 of quantitative methods, 88 each DCT transform matrix quantization (Huffman encoding part can be omitted) thereby achieving the image compression. In the case of a certain compression ratio, and the image quality given by the ⑴ compared. (3) with the given sub-subroutine fast_LOT.m transform and compress the image, and (1) gives the image quality compared Platform: |
Size: 201728 |
Author:zrf |
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Description: 利用离散余弦变换函数（dct2和idct2）模拟JPEG压缩过程。 对“lena.bmp”做压缩，观察压缩效果。（JPEG压缩过程： 首先把原始的图像划分为8×8的子图像，然后利用dct2分别
对各个子图像进行离散余弦变换，对变换系数仅保留左上角15个值， 然后利用这15个系数进行离散余弦反变换重新得到各个子图像，再 将子图像拼接成完整图像） -Using discrete cosine transform function (dct2 and idct2) analog JPEG compression process. On " lena.bmp" do compression, the compression effect was observed. (JPEG compression process: First, the original image is divided into 88 sub-image, and then use dct2 of each sub-image, respectively, discrete cosine transform, the upper left corner of the transform coefficients to retain only 15 values, then use the 15 coefficients discrete cosine transform regain each sub-image, and then sub-images together into a complete picture) Platform: |
Size: 1024 |
Author:付兴银 |
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Description: 对girl图像做二维DCT，并通过对变换后的某些系数置零达到压缩目的-Girl doing two-dimensional images of the DCT, and through certain coefficients transformed to achieve compression purpose of nulling Platform: |
Size: 1024 |
Author:tution |
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Description: dct
The discrete cosine transform (DCT) represents an image as a sum of sinusoids of varying magnitudes and frequencies. The dct2 function computes the two-dimensional discrete cosine transform (DCT) of an image. The DCT has the property that, for a typical image, most of the visually significant information about the image is concentrated in just a few coefficients of the DCT. For this reason, the DCT is often used in image compression applications. For example, the DCT is at the heart of the international standard lossy image compression algorithm known as JPEG. Platform: |
Size: 156672 |
Author:MANJUNATH |
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Description: The discrete cosine transform (DC T) represents an image as a sum of
sinusoids of varying magnitudes and frequencies. The dct2 function
computes the two-dimensional discrete cosine transform (DC T) of an
image. The DC T has the property that, for a typical image, most of the
visually significant information about the image is concentrated in just a few
coefficients of the DC T. For this reason, the DC T is often used in image
compression applications. For example, the DC T is at the heart of the international
standard lossy image compression algorithm known as JPEG. (The name comes
from the working group that developed the standard: the Joint Photographic
Experts Group). In practice, the DC T is normally implemented using the same basic
efficiency techniques as in FFT algorithms Platform: |
Size: 3049472 |
Author:cj |
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Description: 利用dct变化对图像进行压缩，可以根据感谢量化矩阵改变压缩率.-By using DCT changes on image compressing, can according to thank quantization matrix change compression ratio. Platform: |
Size: 1024 |
Author:yang yang |
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Description: 利用函数dct2，对图像进行压缩。并使用量化方法，对每一个经DCT变换后的8×8 矩阵量化，从而实现图像压缩。-Use function dct2, the image compression. And the use of quantitative methods, each DCT transformed matrix 88 after quantization, in order to achieve image compression. Platform: |
Size: 16384 |
Author:赵玉杰 |
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Search - dct2 compression