perception/path/camera/pathnet/docs/pathnet_usecase1.md

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# Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.

@page pathnet_usecase1 PathNet Workflow

## Initialization

PathNet module initialization takes either PathNet module handle or user customized path detection network module handle as an input. To initialize NVIDIA PathNet module:
```{.cpp}
dwStatus dwPathNet_initDefaultParams(dwPathNetParams* pathNetParams);
```

Or to initialize a pointer to a PathNet handle with designated values of `dwPathNetParams` use:
```{.cpp}
dwStatus dwPathNet_initialize(dwPathNetHandle_t *pathNetHandle,
                              const dwPathNetParams *pathNetParams,
                              dwContextHandle_t ctx);
```

An example code snippet to initialize a PathNet module with a customized FP32 PathNet model that is optimized to perfrom inference on GPU:
```{.cpp}
dwPathNetHandle_t pathNet;
dwPathNetParams pathNetParams{};
dwPathNet_initDefaultParams(&pathNetParams);
pathNetParams.networkModel = DW_PATHNET_MODEL_CUSTOM;
pathNetParams.networkCustomData = "my_pathnet_model";
CHECK_DW_ERROR(dwPathNet_initialize(&pathNet, &pathNetParams, context));
```
Note that `dwPathNet_initDefaultParams()` set `pathNetParams.networkPrecision` to the default value of `DW_PRECISION_FP32`. And it is assuming that "my_pathnet_model" file is already present in data/resources sub-directory.

## Query Network Specs

With the provided APIs, you can get the input blob dimension that the initialized PathNet expects:
```{.cpp}
dwStatus dwPathNet_getInputBlobsize(dwBlobSize* inputBlobsize, dwPathNetHandle_t obj);

```

Retrieve the pointer to the path position label of the provided class index:
```{.cpp}
dwStatus dwPathNet_getPathPositionLabel(const char** pathPositionLabel, uint32_t classIdx, dwPathNetHandle_t obj);

```

Or, retrieve the meta data which contains preprocessing configuration for the network:
```{.cpp}
dwStatus dwPathNet_getDNNMetaData(dwDNNMetaData* metaData, dwPathNetHandle_t obj);

```

## PathNet Module Reset

To reset the PathNet module:
```{.cpp}
dwStatus dwPathNet_reset(dwPathNetHandle_t obj);
```

## PathNet Module Release

To release the PathNet module:
```{.cpp}
dwPathNet_release(dwPathNetHandle_t *obj);
```

For more detailed workflow, please refer to the path detection sample: @ref dwx_path_perception_sample.