Refactor PaddleOCR online model loading for ONNX V6

- Merge V6 ONNX detection/classification models into existing online model types
- Add unified online recognition model abstraction with internal V6 ONNX implementation
- Remove obsolete OnlineOnnx* model types and IOnlineModels interfaces
- Default ONNX classification shape for PP-LCNet textline orientation models
- Update V6 full model composition and tests to use consolidated APIs

Author: sdcb

projects/PaddleOCR/Sdcb.OpenVINO.PaddleOCR.Models.Online/IOnlineModels.cs

@@ -13,19 +13,14 @@ namespace Sdcb.OpenVINO.PaddleOCR.Models.Online;
 /// <remarks>
 /// Used for downloading and extracting a model from a url, and creating a new StreamDictFileRecognizationModel with the downloaded contents.
 /// </remarks>
-public record LocalDictOnlineRecognizationModel(string Name, string DictName, Uri Uri, ModelVersion Version) : IOnlineRecognizationModel
+public record LocalDictOnlineRecognizationModel(string Name, string DictName, Uri Uri, ModelVersion Version) : OnlineRecognizationModel(Name, Uri, Version)
 {
-    /// <summary>
-    /// Gets or sets the root directory for the downloaded models.
-    /// </summary>
-    public string RootDirectory => Path.Combine(Settings.GlobalModelDirectory, Name);
-
     /// <summary>
     /// Downloads and extracts a RecognizationModel asynchronously.
     /// </summary>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>The downloaded and extracted RecognizationModel.</returns>
-    public async Task<RecognizationModel> DownloadAsync(CancellationToken cancellationToken = default)
+    public override async Task<RecognizationModel> DownloadAsync(CancellationToken cancellationToken = default)
     {
         await Utils.DownloadAndExtractAsync(Name, Uri, RootDirectory, cancellationToken);
         return new StreamDictFileRecognizationModel(RootDirectory, SharedUtils.LoadDicts(DictName), Version);

projects/PaddleOCR/Sdcb.OpenVINO.PaddleOCR.Models.Online/LocalDictOnlineRecognizationModel.cs

@@ -10,7 +10,7 @@ namespace Sdcb.OpenVINO.PaddleOCR.Models.Online;
 /// <summary>
 /// Represents an online classification model that can be downloaded and used for text angle classification.
 /// </summary>
-public record OnlineClassificationModel(string Name, Uri Uri, ModelVersion Version) : IOnlineClassificationModel
+public record OnlineClassificationModel(string Name, Uri Uri, ModelVersion Version)
 {
     /// <summary>
     /// Gets the root directory of the model.
@@ -21,17 +21,28 @@ public record OnlineClassificationModel(string Name, Uri Uri, ModelVersion Versi
     /// Downloads and extracts the model asynchronously.
     /// </summary>
     /// <param name="cancellationToken">The cancellation token.</param>
-    /// <returns>A <see cref="FileClassificationModel"/> that represent the downloaded model.</returns>
-    public async Task<FileClassificationModel> DownloadAsync(CancellationToken cancellationToken = default)
+    /// <returns>A <see cref="ClassificationModel"/> that represent the downloaded model.</returns>
+    public async Task<ClassificationModel> DownloadAsync(CancellationToken cancellationToken = default)
     {
+        if (Version == ModelVersion.V6)
+        {
+            await Utils.DownloadAndExtractAsync(Name, Uri, RootDirectory, cancellationToken, "inference.onnx", "inference.yml");
+            return new FileOnnxClassificationModel(RootDirectory, Version);
+        }
+
         await Utils.DownloadAndExtractAsync(Name, Uri, RootDirectory, cancellationToken);
         return new FileClassificationModel(RootDirectory, Version);
     }
 
-    async Task<ClassificationModel> IOnlineClassificationModel.DownloadAsync(CancellationToken cancellationToken)
-    {
-        return await DownloadAsync(cancellationToken);
-    }
+    /// <summary>
+    /// PP-LCNet x0.25 ONNX text line orientation model.
+    /// </summary>
+    public static OnlineClassificationModel TextLineOrientationX025 => new("PP-LCNet_x0_25_textline_ori_onnx_infer", new Uri("https://paddle-model-ecology.bj.bcebos.com/paddlex/official_inference_model/paddle3.0.0/PP-LCNet_x0_25_textline_ori_onnx_infer.tar"), ModelVersion.V6);
+
+    /// <summary>
+    /// PP-LCNet x1.0 ONNX text line orientation model.
+    /// </summary>
+    public static OnlineClassificationModel TextLineOrientationX10 => new("PP-LCNet_x1_0_textline_ori_onnx_infer", new Uri("https://paddle-model-ecology.bj.bcebos.com/paddlex/official_inference_model/paddle3.0.0/PP-LCNet_x1_0_textline_ori_onnx_infer.tar"), ModelVersion.V6);
 
     /// <summary>
     /// Gets an online classification model for slim quantized text angle classification (Size: 2.1M).
@@ -48,6 +59,8 @@ async Task<ClassificationModel> IOnlineClassificationModel.DownloadAsync(Cancell
     /// </summary>
     public static OnlineClassificationModel[] All => new[]
     {
+        TextLineOrientationX025,
+        TextLineOrientationX10,
         ChineseMobileSlimV2,
         ChineseMobileV2,
     };

projects/PaddleOCR/Sdcb.OpenVINO.PaddleOCR.Models.Online/OnlineClassificationModel.cs

@@ -10,7 +10,7 @@ namespace Sdcb.OpenVINO.PaddleOCR.Models.Online;
 /// <summary>
 /// Represents a model for online object detection.
 /// </summary>
-public record OnlineDetectionModel(string Name, Uri Uri, ModelVersion Version) : IOnlineDetectionModel
+public record OnlineDetectionModel(string Name, Uri Uri, ModelVersion Version)
 {
     /// <summary>
     /// Gets the root directory of the model.
@@ -21,18 +21,33 @@ public record OnlineDetectionModel(string Name, Uri Uri, ModelVersion Version) :
     /// Downloads and extracts the model files to the root directory asynchronously.
     /// </summary>
     /// <param name="cancellationToken">Cancellation token.</param>
-    /// <returns>A <see cref="FileDetectionModel"/> representing the downloaded and extracted file model.</returns>
-    public async Task<FileDetectionModel> DownloadAsync(CancellationToken cancellationToken = default)
+    /// <returns>A <see cref="DetectionModel"/> representing the downloaded and extracted file model.</returns>
+    public async Task<DetectionModel> DownloadAsync(CancellationToken cancellationToken = default)
     {
-        await Utils.DownloadAndExtractAsync(Name, Uri, RootDirectory, cancellationToken);
+        if (Version == ModelVersion.V6)
+        {
+            await Utils.DownloadAndExtractAsync(Name, Uri, RootDirectory, cancellationToken, "inference.onnx");
+            return new FileOnnxDetectionModel(RootDirectory, Version);
+        }
 
+        await Utils.DownloadAndExtractAsync(Name, Uri, RootDirectory, cancellationToken);
         return new FileDetectionModel(RootDirectory, Version);
     }
 
-    async Task<DetectionModel> IOnlineDetectionModel.DownloadAsync(CancellationToken cancellationToken)
-    {
-        return await DownloadAsync(cancellationToken);
-    }
+    /// <summary>
+    /// PP-OCRv6 medium ONNX detection model.
+    /// </summary>
+    public static OnlineDetectionModel ChineseV6Medium => new("PP-OCRv6_medium_det_onnx_infer", new Uri("https://paddle-model-ecology.bj.bcebos.com/paddlex/official_inference_model/paddle3.0.0/PP-OCRv6_medium_det_onnx_infer.tar"), ModelVersion.V6);
+
+    /// <summary>
+    /// PP-OCRv6 small ONNX detection model.
+    /// </summary>
+    public static OnlineDetectionModel ChineseV6Small => new("PP-OCRv6_small_det_onnx_infer", new Uri("https://paddle-model-ecology.bj.bcebos.com/paddlex/official_inference_model/paddle3.0.0/PP-OCRv6_small_det_onnx_infer.tar"), ModelVersion.V6);
+
+    /// <summary>
+    /// PP-OCRv6 tiny ONNX detection model.
+    /// </summary>
+    public static OnlineDetectionModel ChineseV6Tiny => new("PP-OCRv6_tiny_det_onnx_infer", new Uri("https://paddle-model-ecology.bj.bcebos.com/paddlex/official_inference_model/paddle3.0.0/PP-OCRv6_tiny_det_onnx_infer.tar"), ModelVersion.V6);
 
     /// <summary>
     /// [New] v4 model, supporting Chinese, English, multilingual text detection
@@ -117,6 +132,9 @@ async Task<DetectionModel> IOnlineDetectionModel.DownloadAsync(CancellationToken
     /// </summary>
     public static OnlineDetectionModel[] All => new[]
     {
+        ChineseV6Medium,
+        ChineseV6Small,
+        ChineseV6Tiny,
         ChineseV4,
         ChineseServerV4,
         ChineseV3Slim,

projects/PaddleOCR/Sdcb.OpenVINO.PaddleOCR.Models.Online/OnlineDetectionModel.cs

@@ -11,7 +11,7 @@ namespace Sdcb.OpenVINO.PaddleOCR.Models.Online;
 /// <summary>
 /// Represents an online ONNX document orientation classification model.
 /// </summary>
-public record OnlineDocumentOrientationClassificationModel(string Name, Uri Uri) : IOnlineDocumentOrientationClassificationModel
+public record OnlineDocumentOrientationClassificationModel(string Name, Uri Uri)
 {
     /// <summary>
     /// Gets the root directory of the model.
@@ -27,11 +27,6 @@ public async Task<FileDocumentOrientationClassificationModel> DownloadAsync(Canc
         return new FileDocumentOrientationClassificationModel(RootDirectory);
     }
 
-    async Task<DocumentOrientationClassificationModel> IOnlineDocumentOrientationClassificationModel.DownloadAsync(CancellationToken cancellationToken)
-    {
-        return await DownloadAsync(cancellationToken);
-    }
-
     /// <summary>
     /// PP-LCNet x1.0 document orientation model.
     /// </summary>

projects/PaddleOCR/Sdcb.OpenVINO.PaddleOCR.Models.Online/OnlineDocumentOrientationClassificationModel.cs

@@ -11,10 +11,10 @@ namespace Sdcb.OpenVINO.PaddleOCR.Models.Online;
 /// Contains static instances for commonly used models and a method for downloading a full OCR model.
 /// </remarks>
 public record class OnlineFullModels(
-    IOnlineDetectionModel DetModel,
-    IOnlineClassificationModel? ClsModel,
-    IOnlineRecognizationModel RecModel,
-    IOnlineDocumentOrientationClassificationModel? DocOrientationModel = null)
+    OnlineDetectionModel DetModel,
+    OnlineClassificationModel? ClsModel,
+    OnlineRecognizationModel RecModel,
+    OnlineDocumentOrientationClassificationModel? DocOrientationModel = null)
 {
     /// <summary>
     /// Downloads a full OCR model asynchronously.
@@ -34,27 +34,27 @@ public async Task<FullOcrModel> DownloadAsync(CancellationToken cancellationToke
     /// The Chinese PP-OCRv6 medium ONNX version.
     /// </summary>
     public readonly static OnlineFullModels ChineseV6Medium = new(
-        OnlineOnnxDetectionModel.ChineseV6Medium,
-        OnlineOnnxClassificationModel.TextLineOrientationX10,
-        OnlineOnnxRecognizationModel.ChineseV6Medium,
+        OnlineDetectionModel.ChineseV6Medium,
+        OnlineClassificationModel.TextLineOrientationX10,
+        OnlineRecognizationModel.ChineseV6Medium,
         OnlineDocumentOrientationClassificationModel.PPDocOrientationX10);
 
     /// <summary>
     /// The Chinese PP-OCRv6 small ONNX version.
     /// </summary>
     public readonly static OnlineFullModels ChineseV6Small = new(
-        OnlineOnnxDetectionModel.ChineseV6Small,
-        OnlineOnnxClassificationModel.TextLineOrientationX025,
-        OnlineOnnxRecognizationModel.ChineseV6Small,
+        OnlineDetectionModel.ChineseV6Small,
+        OnlineClassificationModel.TextLineOrientationX025,
+        OnlineRecognizationModel.ChineseV6Small,
         OnlineDocumentOrientationClassificationModel.PPDocOrientationX10);
 
     /// <summary>
     /// The Chinese PP-OCRv6 tiny ONNX version.
     /// </summary>
     public readonly static OnlineFullModels ChineseV6Tiny = new(
-        OnlineOnnxDetectionModel.ChineseV6Tiny,
-        OnlineOnnxClassificationModel.TextLineOrientationX025,
-        OnlineOnnxRecognizationModel.ChineseV6Tiny,
+        OnlineDetectionModel.ChineseV6Tiny,
+        OnlineClassificationModel.TextLineOrientationX025,
+        OnlineRecognizationModel.ChineseV6Tiny,
         OnlineDocumentOrientationClassificationModel.PPDocOrientationX10);
 
     /// <summary>