Mask_R-CNN_demo.py

# coding: utf-8

# # Mask R-CNN demo
# 
# This notebook illustrates one possible way of using `maskrcnn_benchmark` for computing predictions on images from an arbitrary URL.
# 
# Let's start with a few standard imports

# In[1]:


import matplotlib.pyplot as plt
import matplotlib.pylab as pylab

import requests
from io import BytesIO
from PIL import Image
import numpy as np


# In[2]:


# this makes our figures bigger
pylab.rcParams['figure.figsize'] = 20, 12


# Those are the relevant imports for the detection model

# In[3]:


from maskrcnn_benchmark.config import cfg
from predictor import COCODemo


# We provide a helper class `COCODemo`, which loads a model from the config file, and performs pre-processing, model prediction and post-processing for us.
# 
# We can configure several model options by overriding the config options.
# In here, we make the model run on the CPU

# In[4]:


config_file = "../configs/caffe2/e2e_mask_rcnn_R_50_FPN_1x_caffe2.yaml"

# update the config options with the config file
cfg.merge_from_file(config_file)
# manual override some options
cfg.merge_from_list(["MODEL.DEVICE", "cpu"])


# Now we create the `COCODemo` object. It contains a few extra options for conveniency, such as the confidence threshold for detections to be shown.

# In[5]:


coco_demo = COCODemo(
    cfg,
    min_image_size=800,
    confidence_threshold=0.7,
)


# Let's define a few helper functions for loading images from a URL

# In[6]:


def load(url):
    """
    Given an url of an image, downloads the image and
    returns a PIL image
    """
    response = requests.get(url)
    pil_image = Image.open(BytesIO(response.content)).convert("RGB")
    # convert to BGR format
    image = np.array(pil_image)[:, :, [2, 1, 0]]
    return image

def imshow(img):
    plt.imshow(img[:, :, [2, 1, 0]])
    plt.axis("off")


# Let's now load an image from the COCO dataset. It's reference is in the comment

# In[7]:


# from http://cocodataset.org/#explore?id=345434
image = load("http://farm3.staticflickr.com/2469/3915380994_2e611b1779_z.jpg")
imshow(image)


# ### Computing the predictions
# 
# We provide a `run_on_opencv_image` function, which takes an image as it was loaded by OpenCV (in `BGR` format), and computes the predictions on them, returning an image with the predictions overlayed on the image.

# In[8]:


# compute predictions
predictions = coco_demo.run_on_opencv_image(image)
imshow(predictions)