GPT答：

https://ask.gongduoduo.com

步骤如下：

1. 读取lena图像并显示

```matlab
I = imread('lena.jpg');
imshow(I);
```

2. 灰度范围线性扩展

```matlab
a = 0.3;
b = 0.6;
c = 0.1;
d = 0.9;

J_linear = imadjust(I, [a b], [c d]);
figure, imshow(J_linear);
```

3. 灰度范围非线性扩展

```matlab
gamma = 2;

J_nonlinear = imadjust(I, [], [], gamma);
figure, imshow(J_nonlinear);
```

4. 灰度倒置变换

```matlab
J_inverted = imcomplement(I);
figure, imshow(J_inverted);
```

5. 图像二值化

```matlab
level1=0.4;
level2=0.7;

K_binary1=imbinarize(I, level1); 
K_binary2=imbinarize(I, level2); 

figure,
subplot(121),imshow(K_binary1),title('Binary Image (Level=0.4)');
subplot(122),imshow(K_binary2),title('Binary Image (Level=0..7)');
```
这些步骤将实现所需的灰度级变换函数，包括灰度范围线性扩展、非线性扩展、灰度倒置和二值化。