[Model] Support YOLOv8 (#1137)

* add GPL lisence

* add GPL-3.0 lisence

* add GPL-3.0 lisence

* add GPL-3.0 lisence

* support yolov8

* add pybind for yolov8

* add yolov8 readme

Co-authored-by: DefTruth <31974251+DefTruth@users.noreply.github.com>

fastdeploy/vision/detection/contrib/yolov8/postprocessor.h

@@ -0,0 +1,75 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+#include "fastdeploy/vision/common/processors/transform.h"
+#include "fastdeploy/vision/common/result.h"
+
+namespace fastdeploy {
+namespace vision {
+
+namespace detection {
+/*! @brief Postprocessor object for YOLOv8 serials model.
+ */
+class FASTDEPLOY_DECL YOLOv8Postprocessor {
+ public:
+  /** \brief Create a postprocessor instance for YOLOv8 serials model
+   */
+  YOLOv8Postprocessor();
+
+  /** \brief Process the result of runtime and fill to DetectionResult structure
+   *
+   * \param[in] tensors The inference result from runtime
+   * \param[in] result The output result of detection
+   * \param[in] ims_info The shape info list, record input_shape and output_shape
+   * \return true if the postprocess successed, otherwise false
+   */
+  bool Run(const std::vector<FDTensor>& tensors,
+     std::vector<DetectionResult>* results,
+     const std::vector<std::map<std::string, std::array<float, 2>>>& ims_info);
+
+  /// Set conf_threshold, default 0.25
+  void SetConfThreshold(const float& conf_threshold) {
+    conf_threshold_ = conf_threshold;
+  }
+
+  /// Get conf_threshold, default 0.25
+  float GetConfThreshold() const { return conf_threshold_; }
+
+  /// Set nms_threshold, default 0.5
+  void SetNMSThreshold(const float& nms_threshold) {
+    nms_threshold_ = nms_threshold;
+  }
+
+  /// Get nms_threshold, default 0.5
+  float GetNMSThreshold() const { return nms_threshold_; }
+
+  /// Set multi_label, set true for eval, default true
+  void SetMultiLabel(bool multi_label) {
+    multi_label_ = multi_label;
+  }
+
+  /// Get multi_label, default true
+  bool GetMultiLabel() const { return multi_label_; }
+
+ protected:
+  float conf_threshold_;
+  float nms_threshold_;
+  bool multi_label_;
+  float max_wh_;
+};
+
+}  // namespace detection
+}  // namespace vision
+}  // namespace fastdeploy