Hello Classification Python Sample¶
This sample demonstrates how to do inference of image classification models using Synchronous Inference Request API.
Models with only 1 input and output are supported.
The following Python API is used in the application:
Feature |
API |
Description |
---|---|---|
Basic Infer Flow |
openvino.runtime.Core , openvino.runtime.Core.read_model , openvino.runtime.Core.compile_model |
Common API to do inference |
Synchronous Infer |
Do synchronous inference |
|
Model Operations |
openvino.runtime.Model.inputs , openvino.runtime.Model.outputs |
Managing of model |
Preprocessing |
openvino.preprocess.PrePostProcessor , openvino.preprocess.InputTensorInfo.set_element_type , openvino.preprocess.InputTensorInfo.set_layout , openvino.preprocess.InputTensorInfo.set_spatial_static_shape , openvino.preprocess.PreProcessSteps.resize , openvino.preprocess.InputModelInfo.set_layout , openvino.preprocess.OutputTensorInfo.set_element_type , openvino.preprocess.PrePostProcessor.build |
Set image of the original size as input for a model with other input size. Resize and layout conversions will be performed automatically by the corresponding plugin just before inference |
Options |
Values |
---|---|
Validated Models |
|
Model Format |
OpenVINO Intermediate Representation (.xml + .bin), ONNX (.onnx) |
Supported devices |
|
Other language realization |
How It Works¶
At startup, the sample application reads command-line parameters, prepares input data, loads a specified model and image to the OpenVINO™ Runtime plugin, performs synchronous inference, and processes output data, logging each step in a standard output stream.
For more information, refer to the explicit description of Integration Steps in the Integrate OpenVINO Runtime with Your Application.
Running¶
Before running the sample, specify a model and an image:
Use public or Intel’s pre-trained models from Open Model Zoo. The models can be downloaded by using the Model Downloader.
You may use images from the media files collection, available online in the test data storage.
To run the sample, use the following script:
python hello_classification.py <path_to_model> <path_to_image> <device_name>
NOTES :
By default, samples and demos in OpenVINO Toolkit expect input with
BGR
order of channels. If you trained your model to work withRGB
order, you need to manually rearrange the default order of channels in the sample or demo application, or reconvert your model, using Model Optimizer with--reverse_input_channels
argument specified. For more information about the argument, refer to When to Reverse Input Channels section of the Embedding Preprocessing Computation.Before running the sample with a trained model, make sure that the model is converted to the OpenVINO Intermediate Representation (OpenVINO IR) format (*.xml + *.bin) by using Model Optimizer.
The sample accepts models in the ONNX format (.onnx) that do not require preprocessing.
Example¶
Install the
openvino-dev
Python package to use Open Model Zoo Tools:python -m pip install openvino-dev[caffe,onnx,tensorflow2,pytorch,mxnet]
Download a pre-trained model:
omz_downloader --name alexnet
If a model is not in the OpenVINO IR or ONNX format, it must be converted. You can do this using the model converter:
omz_converter --name alexnet
Perform inference of the
banana.jpg
, using thealexnet
model on aGPU
, for example:python hello_classification.py alexnet.xml banana.jpg GPU
Sample Output¶
The sample application logs each step in a standard output stream and outputs top-10 inference results.
[ INFO ] Creating OpenVINO Runtime Core
[ INFO ] Reading the model: /models/alexnet/alexnet.xml
[ INFO ] Loading the model to the plugin
[ INFO ] Starting inference in synchronous mode
[ INFO ] Image path: /images/banana.jpg
[ INFO ] Top 10 results:
[ INFO ] class_id probability
[ INFO ] --------------------
[ INFO ] 954 0.9703885
[ INFO ] 666 0.0219518
[ INFO ] 659 0.0033120
[ INFO ] 435 0.0008246
[ INFO ] 809 0.0004433
[ INFO ] 502 0.0003852
[ INFO ] 618 0.0002906
[ INFO ] 910 0.0002848
[ INFO ] 951 0.0002427
[ INFO ] 961 0.0002213
[ INFO ]
[ INFO ] This sample is an API example. Use the dedicated `benchmark_app` tool for any performance measurements.