image-crop/README.md

# Image Crop Implementation with CV2

*author: David Wang*



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## Description

An image crop operator implementation with OpenCV.



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## Code Example

Crop the face from 'avengers.jpg'.

```python

import towhee

towhee.glob['path']('./avengers.jpg') \
  .image_decode['path', 'img']() \
  .face_detection.retinaface['img', ('box','score')]()\
  .image_crop[('img', 'box'), 'crop'](clamp = True)\
  .select['img','crop']()\
  .show()
```


<img src="./result2.png" height="150px"/>

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## Factory Constructor

Create the operator via the following factory method

***image_crop(clamp = True)***


**Parameters:**

**clamp:** *bool*

​ If set True, coordinates of bounding boxes would be clamped into image size.

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## Interface

An image crop operator takes an image and bounding boxes as input. It cropes the image into ROIs(region of interest).


**Parameters:**

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

​	The image need to be cropped.

**bboxes:** *numpy.ndarray* 

​	The nx4 numpy tensor for n bounding boxes need to crop, each row is formatted as (x1, y1, x2, y2).

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

​	The cropped image data as numpy.ndarray.