Add README

Signed-off-by: shiyu22 <shiyu.chen@zilliz.com>

README.md

@@ -8,7 +8,7 @@ An image embedding pipeline generates a vector given an image. This Pipeline ext
 
 ## Code Example
 
-- Create image embedding pipeline with the default configuration.
+### Create pipeline with the default configuration
 
 ```python
 from towhee import AutoPipes
@@ -18,9 +18,9 @@ res = p('https://github.com/towhee-io/towhee/raw/main/towhee_logo.png')
 res.get()
 ```
 
-- Create image embedding pipeline and set the configuration.
+### Create pipeline and set the configuration
 
-> More parameters refer to the API Interface.
+> More parameters refer to the Configuration.
 
 ```python
 from towhee import AutoPipes, AutoConfig
@@ -35,9 +35,9 @@ res.get()
 
 
 
-## **Interface**
+## **Configuration**
 
-**ImageEmbeddingConfig**
+### **ImageEmbeddingConfig**
 
 > You can find some parameters in [image_decode.cv2](https://towhee.io/image-decode/cv2) and [image_embedding.timm](https://towhee.io/image-embedding/timm) operators.
 
@@ -63,5 +63,17 @@ The number of GPU device, defaults to -1, which means using CPU.
 
 
 
+## Interface
 
+Encode the image and generate embedding vectors.
+
+**Parameters:**
+
+ ***img***: str
+
+Path or url of the image to be loaded.
+
+**Returns:** np.ndarray
+
+ Embedding vectors to represent the image.