cv2/README.md

# Image Decode Implementation with CV2

*author: Kaiyuan Hu, Rentong Guo*



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## Description

An image decode operator implementation with OpenCV. 



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## Code Example

Load a image from path './src_dog.jpg'. 

the src picture:
<br />
<img src="./src_dog.jpg" height="150px"/>

 *Write the pipeline in simplified style:*

```python
from towhee.dc2 import pipe, ops, DataCollection


# decode image, in bgr channel order
p = (
  pipe.input('url')
  .map('url', 'image', ops.image_decode.cv2())
  .output('image')
)

# decode image, in rgb channel order
p2 = (
  pipe.input('url')
  .map('url', 'image', ops.image_decode.cv2('rgb'))
  .output('image')
)

# decode from path
DataCollection(p('./src_dog.jpg')).show()

# decode from bytes
with open('./src_dog.jpg', 'rb') as f:
  DataCollection(p2(f.read())).show()
```

<br />
<img src="./dog.png" height="150px"/>
<img src="./src_dog.jpg" height="150px"/>



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## Factory Constructor

Create the operator via the following factory method:

***ops.image_decode.cv2()***

**mode**: *str*

BGR or RGB, default is BGR


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## Interface

An image decode operator takes an image path as input. It decodes the image back to ndarray.



**Parameters:**

**img**: *str*

​	Local file path/http url/image bytes.



**Returns**: *towhee.types.Image (a sub-class of numpy.ndarray)* 

​	The decoded image data as numpy.ndarray.