# Image Classification Sample

This topic demonstrates how to build and run the Image Classification sample application, which does 
inference using image classification networks like AlexNet and GoogLeNet.

## Running

Running the application with the <code>-h</code> option yields the following usage message:
```sh
./classification_sample -h
InferenceEngine: 
    API version ............ <version>
    Build .................. <number>

classification_sample [OPTION]
Options:

    -h                      
                            Print a usage message.
    -i "<path1>" "<path2>"
                            Required. Path to a folder with images or path to an image files: a .ubyte file for LeNet
                            and a .bmp file for the other networks.
    -m "<path>"             
                            Required. Path to an .xml file with a trained model.
        -l "<absolute_path>"
                            Optional. Absolute path to library with MKL-DNN (CPU) custom layers (*.so).
        Or
        -c "<absolute_path>"
                            Optional. Absolute path to clDNN (GPU) custom layers config (*.xml).
    -pp "<path>"            
                            Path to a plugin folder.
    -d "<device>"           
                            Specify the target device to infer on; CPU, GPU, FPGA or MYRIAD is acceptable. Sample will look for a suitable plugin for device specified
    -nt "<integer>"         
                            Number of top results (default 10)
    -ni "<integer>"         
                            Number of iterations (default 1)
    -pc                     
                            Enables per-layer performance report
    -p_msg                  
                            Enables messages from a plugin

```

Running the application with the empty list of options yields the usage message given above and an error message.

You can do inference on an image using a trained AlexNet network on Intel&reg; Processors using the following command:
```sh
./classification_sample -i <path_to_image>/cat.bmp -m <path_to_model>/alexnet_fp32.xml
```

### Outputs

By default the application outputs top-10 inference results. 
Add the <code>-nt</code> option to the previous command to modify the number of top output results.
<br>For example, to get the top-5 results on Intel&reg; HD Graphics, use the following commands:
```sh
./classification_sample -i <path_to_image>/cat.bmp -m <path_to_model>/alexnet_fp32.xml -nt 5 -d GPU
```

### How it works

Upon the start-up the sample application reads command line parameters and loads a network and an image to the Inference 
Engine plugin. When inference is done, the application creates an 
output image and outputs data to the standard output stream.

## See Also 
* [Using Inference Engine Samples](./docs/Inference_Engine_Developer_Guide/Samples_Overview.md)