[GitHub] prathik-naidu opened a new issue #12063: MxNet Pre-trained Prediction Doc Not Working

[GitBox <gi...@apache.org>]

prathik-naidu opened a new issue #12063: MxNet Pre-trained Prediction Doc Not Working
URL: https://github.com/apache/incubator-mxnet/issues/12063
 
 
   ## Description
   The predict image doc page: [https://mxnet.incubator.apache.org/tutorials/python/predict_image.html](url) doesn't work right off the shelf (returns incorrect predictions).
   
   ## Problem
   The tutorial doesn't normalize the images – causing incorrect predictions to be made. For newcomers to MxNet/deep learning, I think this is a simple, but useful addition to add in.
   
   ## Solution
   Add in a color normalization in the get_image method as follows:
   
   ```python
   def get_image(url, show=False):
       # download and show the image. Remove query string from the file name.
       fname = mx.test_utils.download(url, fname=url.split('/')[-1].split('?')[0])
       img = mx.image.imread(fname)
       if img is None:
           return None
       if show:
           plt.imshow(img.asnumpy())
           plt.axis('off')
       # convert into format (batch, RGB, width, height)
       img = mx.image.imresize(img, 224, 224) # resize
       #---------------------------
       img = img.astype(float)/255
       img = mx.image.color_normalize(img,
                  mean=mx.nd.array([0.485, 0.456, 0.406]).astype(float), 
                  std=mx.nd.array([0.229, 0.224, 0.225]).astype(float)
       #---------------------------
       img = img.transpose((2, 0, 1)) # Channel first
       img = img.expand_dims(axis=0) # batchify
       return img
   ```
   
   
   
   

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