perception/landmarks/camera/docs/usecase_roadmark_classification.md

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# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.

@page roadmark_classification_usecase Road Mark Classification Workflow

The following code snippet shows the general structure of a program that uses roadmarknet classifier to classify detected road markings on a single camera. Note that error handling is left out for clarity.

Initialize `RoadMarkNet` with default parameters:
```{.cpp}
dwRoadMarkNetHandle_t roadMarkNet;
dwRoadMarkNetParams roadMarkNetParams{};
dwRoadMarkNet_initDefaultParams(&roadMarkNetParams, context);
dwRoadMarkNet_initialize(&roadMarkNet, &roadMarkNetParams, context);
```

Initialize `RoadMarkClasssifier` module from initialized `RoadMarkNet` handle, with parameters `classifierParams`:
```{.cpp}
dwRoadMarkClassifierParams classifierParams = {};
dwRoadMarkClassifier_initDefaultParams(&classifierParams);
dwRoadMarkClassifierHandle_t roadMarkClassifier;
dwRoadMarkClassifier_initializeFromRoadMarkNet(
    &roadMarkClassifier,
    roadMarkNet,
    &classifierParams,
    context);
```

Bind inputs and output to the `RoadMarkClasssifier` module:
```{.cpp}
dwRoadMarkClassifier_bindInputImageArray(&imageArray, imageCount, roadMarkClassifier);
dwRoadMarkClassifier_bindInputRoadmarkDetection(&roadmarkDetectionOutput, roadMarkClassifier);
dwRoadMarkClassifier_bindOutput(&roadmarkClassifierOutput, roadMarkClassifier);
```

Classify detected road markings from the provided inputs:
```{.cpp}
dwRoadMarkClassifier_process(DW_ROADMARK_CLASSIFIER_STAGE_GPU_ASYNC_PREPROCESSING, roadMarkClassifier);
dwRoadMarkClassifier_process(DW_ROADMARK_CLASSIFIER_STAGE_GPU_ASYNC_INFERENCE, roadMarkClassifier);
dwRoadMarkClassifier_process(DW_ROADMARK_CLASSIFIER_STAGE_GPU_ASYNC_INTERPRETATION, roadMarkClassifier);
dwRoadMarkClassifier_process(DW_ROADMARK_CLASSIFIER_STAGE_CPU_SYNC_POSTPROCESSING, roadMarkClassifier);
```

When finished, release the module handles:
```{.cpp}
dwRoadMarkClassifier_release(roadMarkClassifier);
dwRoadMarkNet_release(roadMarkNet);
```

For more detailed workflow, please refer to the road mark classification sample: @ref dwx_roadmark_classification_sample