# 甲壳虫乐队
一只甲壳虫想组个乐队,但是临时找不到队友。请使用 OpenCV 读取下面的彩色甲壳虫图片 `'bug.jpg'`,帮助他变身灰色甲壳虫,然后完成组队。
![](https://gitcode.net/csdn/skill_tree_git_md_linux/-/raw/master/data/1.OpenCV初阶/1.OpenCV基础/4.IO与GUI/bug.jpg)
**显示甲壳虫乐队并写入到 `'bug_band.jpg'`**:
![](https://gitcode.net/csdn/skill_tree_git_md_linux/-/raw/master/data/1.OpenCV初阶/1.OpenCV基础/4.IO与GUI/bug_band.jpg)
以下实现正确的是?
## 答案
```python
import numpy as np
import cv2
if __name__ == '__main__':
bug_img = cv2.imread("bug.jpg")
bug_img_gray = cv2.cvtColor(bug_img, cv2.COLOR_BGR2GRAY)
bug_img_gray_by_BGR_space = cv2.cvtColor(bug_img_gray, cv2.COLOR_GRAY2BGR)
bug_img_concat = np.concatenate(
(bug_img, bug_img_gray_by_BGR_space),
axis=1
)
cv2.imwrite("bug_band.jpg", bug_img_concat)
cv2.imshow('甲壳虫乐队', bug_img_concat)
cv2.waitKey(0)
cv2.destroyAllWindows()
```
## 选项
### 读写api名字错误
```python
import numpy as np
import cv2
if __name__ == '__main__':
bug_img = cv2.read("bug.jpg")
bug_img_gray = cv2.cvtColor(bug_img, cv2.COLOR_BGR2GRAY)
bug_img_gray_by_BGR_space = cv2.cvtColor(bug_img_gray, cv2.COLOR_GRAY2BGR)
bug_img_concat = np.concatenate(
(bug_img, bug_img_gray_by_BGR_space),
axis=1
)
cv2.write("bug_band.jpg", bug_img_concat)
cv2.imshow('甲壳虫乐队', bug_img_concat)
cv2.waitKey(0)
cv2.destroyAllWindows()
```
### 写入参数顺序错误
```python
import numpy as np
import cv2
if __name__ == '__main__':
bug_img = cv2.imread("bug.jpg")
bug_img_gray = cv2.cvtColor(bug_img, cv2.COLOR_BGR2GRAY)
bug_img_gray_by_BGR_space = cv2.cvtColor(bug_img_gray, cv2.COLOR_GRAY2BGR)
bug_img_concat = np.concatenate(
(bug_img, bug_img_gray_by_BGR_space),
axis=1
)
cv2.imwrite(bug_img_concat, "bug_band.jpg")
cv2.imshow('甲壳虫乐队', bug_img_concat)
cv2.waitKey(0)
cv2.destroyAllWindows()
```
### 不能合并彩色和灰色,尺寸不同
```python
import numpy as np
import cv2
if __name__ == '__main__':
bug_img = cv2.imread("bug.jpg")
bug_img_gray = cv2.cvtColor(bug_img, cv2.COLOR_BGR2GRAY)
bug_img_concat = np.concatenate(
(bug_img, bug_img_gray),
axis=1
)
cv2.imwrite("bug_img_concat.jpg", bug_img_concat)
cv2.imshow('甲壳虫乐队', bug_img_gray)
cv2.waitKey(0)
cv2.destroyAllWindows()
```