ImageFeatureDescriptor 类

定义

命名空间:

Windows.AI.MachineLearning

描述模型期望的图像的属性。

public ref class ImageFeatureDescriptor sealed : ILearningModelFeatureDescriptor

/// [Windows.Foundation.Metadata.ContractVersion(Windows.AI.MachineLearning.MachineLearningContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
class ImageFeatureDescriptor final : ILearningModelFeatureDescriptor

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.AI.MachineLearning.MachineLearningContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
public sealed class ImageFeatureDescriptor : ILearningModelFeatureDescriptor

Public NotInheritable Class ImageFeatureDescriptor
Implements ILearningModelFeatureDescriptor

继承

Object Platform::Object IInspectable ImageFeatureDescriptor

属性

ContractVersionAttribute MarshalingBehaviorAttribute

实现

ILearningModelFeatureDescriptor

Windows 要求

设备系列	Windows 10, version 1809 (在 10.0.17763.0 中引入)
API contract	Windows.AI.MachineLearning.MachineLearningContract (在 v1.0 中引入)

示例

以下示例从本地文件加载模型，从该文件创建会话，并获取输入和输出特征。

private async Task LoadModelAsync(string _modelFileName)
{
    LearningModel _model;
    LearningModelSession _session;
    ImageFeatureDescriptor _inputImageDescription;
    TensorFeatureDescriptor _outputImageDescription;

    try
    {
        // Load and create the model
        var modelFile = 
            await StorageFile.GetFileFromApplicationUriAsync(new Uri($"ms-appx:///Assets/{_modelFileName}"));
        _model = await LearningModel.LoadFromStorageFileAsync(modelFile);

        // Create the evaluation session with the model
        _session = new LearningModelSession(_model);

        //Get input and output features of the model
        List<ILearningModelFeatureDescriptor> inputFeatures = _model.InputFeatures.ToList();
        List<ILearningModelFeatureDescriptor> outputFeatures = _model.OutputFeatures.ToList();

        // Retrieve the first input feature which is an image
        _inputImageDescription = inputFeatures.FirstOrDefault(
            feature => feature.Kind == LearningModelFeatureKind.Image) as ImageFeatureDescriptor;

        // Retrieve the first output feature which is a tensor
        _outputImageDescription = outputFeatures.FirstOrDefault(
            feature => feature.Kind == LearningModelFeatureKind.Tensor) as TensorFeatureDescriptor;
    }
    catch (Exception ex)
    {
        StatusBlock.Text = $"error: {ex.Message}";
        _model = null;
    }
}

注解

Windows Server

若要在 Windows Server 上使用此 API，必须使用带桌面体验的 Windows Server 2019。

线程安全

此 API 是线程安全的。

属性

BitmapAlphaMode	指定图像的预期 alpha 模式。
BitmapPixelFormat	指定预期的像素格式 (通道排序、位深度和数据类型) 。
Description	描述此功能在模型中的用途。
Height	预期的图像高度。
IsRequired	如果为 true，则必须在调用 LearningModelSession.Evaluate 之前将值绑定到此功能。
Kind	功能类型 - 使用此类型可知道要使用哪个派生类。
Name	用于将值绑定到此功能的名称。
PixelRange	提供用于模型的预期 LearningModelPixelRange 信息。
Width	预期的图像宽度。

另请参阅

• Windows ML
• Windows ML 示例 (GitHub)