FINSENTY54

mat2gray 将dicom变为grey
im2uint8

dicom （a image type using in medical)

To read metadata from a DICOM file, use the dicominfo function

To readimage datafrom a DICOM file, use the dicomread function.

对比度

histogram 直方图
Precede the call to imhist with the figure command so that the histogram does not overwrite the display of the image I in the current figure window.

To see the distribution of intensities in the image, create a histogram by calling the imhist function.
输入图片，图片要求为灰度图或者二值图 imhist

使用基于帕斯卡三角形的项创建一个对称矩阵：
A = pascal(3)

randi 的第一个输入描述整数可能值的范围，后面两个输入描述行和列的数量。
C = randi(10,3,2)

有一个专门的点积函数，称为 dot。

B = A - 8.5
B(1:2,2:3) = 0
x = [2.1 1.7 1.6 1.5 NaN 1.9 1.8 1.5 5.1 1.8 1.4 2.2 1.6 1.8];
x = x(isfinite(x))
x =
  2.1 1.7 1.6 1.5 1.9 1.8 1.5 5.1 1.8 1.4 2.2 1.6 1.8
x = x(abs(x-mean(x)) <= 3*std(x))
x =
  2.1 1.7 1.6 1.5 1.9 1.8 1.5 1.8 1.4 2.2 1.6 1.8

科学记数法使用字母 e 来指定 10 次方的缩放因子
浮点数的有限精度约为 16 位有效小数位数，有限范围约为 10-308 至 10+308。双精度格式表示的数字的最大精度为 52 位。整数的可用精度为 8 位、16 位、32 位和 64 位

x = uint64(36028797018963968);
y = uint64(36028797018963972);

处理文本时，将字符序列括在单引号中。可以将文本赋给变量。
myText = 'Hello, world';
如果文本包含单引号，使用两个单引号。

otherText = 'You''re right'
otherText = 
'You're right'

a = [1 2 3 4]
创建矩阵的另一种方法是使用 ones、zeros 或 rand 等函数。例如，创建一个由零组成的 5×1 列向量。
z = zeros(5,1)

MATLAB 允许您使用单一的算术运算符或函数来处理矩阵中的所有值。
a + 10

orthonormal matrices 正交矩阵
a message can be hidden in cover document if the content of the document hashigh redundancy.
propose a new reliable method by hiding the encrypted watermark in the RONI part of the medical image using DWT approach.
ROI Based Medical Image Watermarking with Zero Distortion and Enhanced Security 所读论文

直方图均衡化（Histogram Equalization）

There are a wide variety of popular wavelet algorithms, including Daubechies wavelets, Mexican Hat wavelets and Morlet wavelets

HAAR

In addition, the Haar wavelet transform is fast, memory efficient and exactly reversible without the edge effects that are present in other wavelet transforms.

the water-mark can be embedded into the other three sub-bands (HL, LH and HH sub-band) to maintain better image quality.