yolov8seg 瑞芯微RKNN芯片、地平线Horizon芯片、TensorRT部署

  特别说明：参考官方开源的yolov8代码、瑞芯微官方文档、地平线的官方文档，如有侵权告知删，谢谢。

  模型、测试图像、测试结果、完整代码，放在github上，参考链接 模型和代码。

  由于之前写了三篇yolov8检测部署板端芯片相关的博文，有网友让写一篇yolov8seg部署博客，一直迟迟未行动，最近忙中借闲匆匆对yolov8seg进行了梳理，尝试了对yolov8seg进行部署验证和仿真测试。总体感受，yolov8的检测由于使用DFL，使得（检测+后处理）相对慢不少，如果把DFL模块相关的放模型里做导致模型慢不少，如果放后处理中做后处理慢（到底是放模型中做还是放后处理中做，根据整个系统的资源合理放置，本示例中是放在模型中进行的）；yolov8seg 还需处理mask系数，同时分割结果还需乘以系数，使得对板端部署不是很友好。

  特别说明：本示例中模型的训练使用的数据并不是很多，模型效果无法保证，只是用来测试部署用的，如果换一张图像可能存在检测不到属于正常现象。分割相关的后处理可能对板端部署还不是很优化，欢迎共同探讨优化。

1 模型和训练

  训练代码参考官方开源的yolov8seg 训练代码，由于SiLU在有些板端芯片上还不支持，因此将其改为ReLU，训练数据集是coco的一部分训练的，主要是用来测试流程用，模型效果无法保证，换一张图像测试检测不到正常。

2 导出 yolov8seg 的 onnx

  本实例提供的导出onnx方式只适配本示例对应仓库的代码，如果用官方导出的onnx，请自行写后处理代码。谢谢

  后处理中有些算在板端芯片上效率低或者不支持，导出 onnx 需要将板端芯片不友好或不支持算子规避掉。导出onnx修改的部分。
第一步：
将pt只保存权重值，增加代码如下图。

        # 保存权重值
        import torch
        self.model.fuse()
        self.model.eval()
        torch.save(self.model.state_dict(), './weights/yolov8n-seg_relu_80class_dict.pt')

修改后运行以下代码（在weights文件夹下生成yolov8n-seg_relu_80class_dict.pt）：

model = YOLO('./weights/yolov8n-seg_relu_80class.pt')
result = model(task='segment', mode='predict', source='./images/test.jpg', line_width=3, show=True, save=True, device='cpu')

第二步：
导出onnx，去除不需要的算子。修改代码如下。
（1）修改检测头

修改该模块的完整代码：

class Detect(nn.Module):
    """YOLOv8 Detect head for detection models."""
    dynamic = False  # force grid reconstruction
    export = False  # export mode
    shape = None
    anchors = torch.empty(0)  # init
    strides = torch.empty(0)  # init

    def __init__(self, nc=80, ch=()):  # detection layer
        super().__init__()
        self.nc = nc  # number of classes
        self.nl = len(ch)  # number of detection layers
        self.reg_max = 16  # DFL channels (ch[0] // 16 to scale 4/8/12/16/20 for n/s/m/l/x)
        self.no = nc + self.reg_max * 4  # number of outputs per anchor
        self.stride = torch.zeros(self.nl)  # strides computed during build
        c2, c3 = max((16, ch[0] // 4, self.reg_max * 4)), max(ch[0], self.nc)  # channels
        self.cv2 = nn.ModuleList(
            nn.Sequential(Conv(x, c2, 3), Conv(c2, c2, 3), nn.Conv2d(c2, 4 * self.reg_max, 1)) for x in ch)
        self.cv3 = nn.ModuleList(nn.Sequential(Conv(x, c3, 3), Conv(c3, c3, 3), nn.Conv2d(c3, self.nc, 1)) for x in ch)
        self.dfl = DFL(self.reg_max) if self.reg_max > 1 else nn.Identity()

        # 导出 onnx 增加
        self.conv1x1 = nn.Conv2d(16, 1, 1, bias=False).requires_grad_(False)
        x = torch.arange(16, dtype=torch.float)
        self.conv1x1.weight.data[:] = nn.Parameter(x.view(1, 16, 1, 1))

    def forward(self, x):
        """Concatenates and returns predicted bounding boxes and class probabilities."""
        shape = x[0].shape  # BCHW
        y = []
        for i in range(self.nl):
            t1 = self.cv2[i](x[i])
            t2 = self.cv3[i](x[i])
            y.append(self.conv1x1(t1.view(t1.shape[0], 4, 16, -1).transpose(2, 1).softmax(1)))
            # y.append(t2.sigmoid())
            y.append(t2)
        return y

        for i in range(self.nl):
            x[i] = torch.cat((self.cv2[i](x[i]), self.cv3[i](x[i])), 1)
        if self.training:
            return x
        elif self.dynamic or self.shape != shape:
            self.anchors, self.strides = (x.transpose(0, 1) for x in make_anchors(x, self.stride, 0.5))
            self.shape = shape

        x_cat = torch.cat([xi.view(shape[0], self.no, -1) for xi in x], 2)
        if self.export and self.format in ('saved_model', 'pb', 'tflite', 'edgetpu', 'tfjs'):  # avoid TF FlexSplitV ops
            box = x_cat[:, :self.reg_max * 4]
            cls = x_cat[:, self.reg_max * 4:]
        else:
            box, cls = x_cat.split((self.reg_max * 4, self.nc), 1)
        dbox = dist2bbox(self.dfl(box), self.anchors.unsqueeze(0), xywh=True, dim=1) * self.strides
        y = torch.cat((dbox, cls.sigmoid()), 1)           # 官方代码
        # y = torch.cat((self.dfl(box), cls.sigmoid()), 1)    # 导出本实例的onnx使用
        return y if self.export else (y, x)

    def bias_init(self):
        """Initialize Detect() biases, WARNING: requires stride availability."""
        m = self  # self.model[-1]  # Detect() module
        # cf = torch.bincount(torch.tensor(np.concatenate(dataset.labels, 0)[:, 0]).long(), minlength=nc) + 1
        # ncf = math.log(0.6 / (m.nc - 0.999999)) if cf is None else torch.log(cf / cf.sum())  # nominal class frequency
        for a, b, s in zip(m.cv2, m.cv3, m.stride):  # from
            a[-1].bias.data[:] = 1.0  # box
            b[-1].bias.data[:m.nc] = math.log(5 / m.nc / (640 / s) ** 2)  # cls (.01 objects, 80 classes, 640 img)

（2）修改分割头

class Segment(Detect):
    """YOLOv8 Segment head for segmentation models."""

    def __init__(self, nc=80, nm=32, npr=256, ch=()):
        """Initialize the YOLO model attributes such as the number of masks, prototypes, and the convolution layers."""
        super().__init__(nc, ch)
        self.nm = nm  # number of masks
        self.npr = npr  # number of protos
        self.proto = Proto(ch[0], self.npr, self.nm)  # protos
        self.detect = Detect.forward

        c4 = max(ch[0] // 4, self.nm)
        self.cv4 = nn.ModuleList(nn.Sequential(Conv(x, c4, 3), Conv(c4, c4, 3), nn.Conv2d(c4, self.nm, 1)) for x in ch)

    def forward(self, x):
        """Return model outputs and mask coefficients if training, otherwise return outputs and mask coefficients."""
        p = self.proto(x[0])  # mask protos
        bs = p.shape[0]  # batch size

        # mc = torch.cat([self.cv4[i](x[i]).view(bs, self.nm, -1) for i in range(self.nl)], 2)  # mask coefficients
        mc = [self.cv4[i](x[i]) for i in range(self.nl)]
        x = self.detect(self, x)
        return x, mc, p
        if self.training:
            return x, mc, p
        return (torch.cat([x, mc], 1), p) if self.export else (torch.cat([x[0], mc], 1), (x[1], mc, p))

（3）添加生成onnx代码

    def _new(self, cfg: str, task=None, verbose=True):
        """
        Initializes a new model and infers the task type from the model definitions.
        Args:
            cfg (str): model configuration file
            task (str) or (None): model task
            verbose (bool): display model info on load
        """
        cfg_dict = yaml_model_load(cfg)
        self.cfg = cfg
        self.task = task or guess_model_task(cfg_dict)
        self.model = TASK_MAP[self.task][0](cfg_dict, verbose=verbose and RANK == -1)  # build model
        self.overrides['model'] = self.cfg

        # Below added to allow export from yamls
        args = {**DEFAULT_CFG_DICT, **self.overrides}  # combine model and default args, preferring model args
        self.model.args = {k: v for k, v in args.items() if k in DEFAULT_CFG_KEYS}  # attach args to model
        self.model.task = self.task

        import torch
        self.model.fuse()
        self.model.eval()
        self.model.load_state_dict(torch.load('./weights/yolov8n-seg_relu_80class_dict.pt', map_location='cpu'), strict=False)

        print("===========  onnx =========== ")
        dummy_input = torch.randn(1, 3, 640, 640)
        input_names = ["data"]
        output_names = ["cls1", "reg1", "cls2", "reg2", "cls3", "reg3", "mc1", "mc2", "mc3", "seg"]
        torch.onnx.export(self.model, dummy_input, "./weights/yolov8n-seg_relu_80class.onnx", verbose=False, input_names=input_names, output_names=output_names, opset_version=11)
        print("======================== convert onnx Finished! .... ")

修改完以上三块，运行以下代码（生成onnx模型）：

model = YOLO('./ultralytics/models/v8/yolov8-seg.yaml')

注意：以上修改顺序一定不能错，两次运行的代码也不一样，请注意，请注意，请注意。

3 yolov8seg 的pytoch 和onnx 测试结果

（1）pytorch测试结果

（2）onnx测试结果

4 瑞芯微rknn和地平线horizon仿真测试参考

  瑞芯微环境搭建和详细步骤参考 【瑞芯微RKNN模型转换和PC端仿真】。

  地平线环境搭建和详细步骤参考【地平线Horizon模型转换和PC端仿真测试】。

5 相关链接

yolov8 检测瑞芯微RKNN和地平线Horizon芯片仿真测试部署

yolov8 瑞芯微 RKNN 的 C++部署

yolov8 导出官方模型进行瑞芯微RKNN和地平线Horizon芯片仿真测试部署