image-crop/README.md

# Image Crop Implementation with CV2

*author: David Wang*



<br />



## Description

An image crop operator implementation with OpenCV.



<br />



## Code Example

Crop the face from 'avengers.jpg'.


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

p = (
    pipe.input('path')
        .map('path', 'img', ops.image_decode())
        .map('img', ('box','score'), ops.face_detection.retinaface())
        .map(('img', 'box'), 'crop', ops.image_crop(clamp = True))
        .output('img', 'crop')
)

DataCollection(p('./avengers.jpg')).show()
```

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

<br />



## 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.

<br />



## 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.