# 多设备

对于许多应用来说，同时使用 多个 OAK 相机 非常有用，因为更多的相机可以感知更多（周围的世界）。例如：

 * [盒子测量](https://github.com/luxonis/oak-examples/tree/master/gen2-box_measurement) 应用，来自多个 不同视角 的相机可以提供更好的尺寸估计。
 * [人员计数/追踪](https://github.com/luxonis/oak-examples/tree/master/gen2-people-tracker#gen2-people-tracker) 应用，多个相机可以
   在广阔区域（例如购物中心）计数/追踪人员。
 * 在机器人正面/背面/左侧/右侧安装多个相机，实现全 360° 视觉，使 机器人无论朝何方向都能感知周围环境。

本示例演示如何在一台主机上使用多个 OAK 相机。演示程序会查找连接到主机的所有设备，并显示每个相机的 RGB 预览。

一个从多个相机进行物体检测的演示应用可在 [此处找到](https://github.com/luxonis/oak-examples/tree/master/gen2-multiple-devices)。

## 演示

```bash
Connected to  18443010F105060F00
        >>> MXID: 18443010F105060F00
        >>> Num of cameras: 3
        >>> USB speed: UsbSpeed.SUPER
        >>> Board name: DM9098
        >>> Product name: OAK-D S2 FF
    Connected to  1844301011F4C51200
        >>> MXID: 1844301011F4C51200
        >>> Num of cameras: 3
        >>> USB speed: UsbSpeed.UNKNOWN
        >>> Board name: NG9097
        >>> Product name: OAK-D Pro PoE AF
```

## 设置

请运行[安装脚本](https://github.com/luxonis/depthai-python/blob/main/examples/install_requirements.py)以下载所有必需的依赖项。请注意，此脚本必须在 git
上下文中运行，因此您需要先下载 [depthai-python](https://github.com/luxonis/depthai-python) 仓库，然后运行该脚本。

```bash
git clone https://github.com/luxonis/depthai-python.git
cd depthai-python/examples
python3 install_requirements.py
```

更多信息，请参考[安装指南](https://docs.luxonis.com/software/depthai/manual-install.md)。

## 源代码

#### Python

```python
#!/usr/bin/env python3

import cv2
import depthai as dai
import contextlib

def createPipeline():
    # Start defining a pipeline
    pipeline = dai.Pipeline()
    # Define a source - color camera
    camRgb = pipeline.create(dai.node.ColorCamera)

    camRgb.setPreviewSize(300, 300)
    camRgb.setBoardSocket(dai.CameraBoardSocket.CAM_A)
    camRgb.setResolution(dai.ColorCameraProperties.SensorResolution.THE_1080_P)
    camRgb.setInterleaved(False)

    # Create output
    xoutRgb = pipeline.create(dai.node.XLinkOut)
    xoutRgb.setStreamName("rgb")
    camRgb.preview.link(xoutRgb.input)

    return pipeline

with contextlib.ExitStack() as stack:
    deviceInfos = dai.Device.getAllAvailableDevices()
    usbSpeed = dai.UsbSpeed.SUPER
    openVinoVersion = dai.OpenVINO.Version.VERSION_2021_4

    qRgbMap = []
    devices = []

    for deviceInfo in deviceInfos:
        deviceInfo: dai.DeviceInfo
        device: dai.Device = stack.enter_context(dai.Device(openVinoVersion, deviceInfo, usbSpeed))
        devices.append(device)
        print("===Connected to ", deviceInfo.getMxId())
        mxId = device.getMxId()
        cameras = device.getConnectedCameras()
        usbSpeed = device.getUsbSpeed()
        eepromData = device.readCalibration2().getEepromData()
        print("   >>> MXID:", mxId)
        print("   >>> Num of cameras:", len(cameras))
        print("   >>> USB speed:", usbSpeed)
        if eepromData.boardName != "":
            print("   >>> Board name:", eepromData.boardName)
        if eepromData.productName != "":
            print("   >>> Product name:", eepromData.productName)

        pipeline = createPipeline()
        device.startPipeline(pipeline)

        # Output queue will be used to get the rgb frames from the output defined above
        q_rgb = device.getOutputQueue(name="rgb", maxSize=4, blocking=False)
        stream_name = "rgb-" + mxId + "-" + eepromData.productName
        qRgbMap.append((q_rgb, stream_name))

    while True:
        for q_rgb, stream_name in qRgbMap:
            if q_rgb.has():
                cv2.imshow(stream_name, q_rgb.get().getCvFrame())

        if cv2.waitKey(1) == ord('q'):
            break
```

#### C++

```cpp
#include <chrono>
#include <iostream>

// Includes common necessary includes for development using depthai library
#include "depthai/depthai.hpp"

std::shared_ptr<dai::Pipeline> createPipeline() {
    // Start defining a pipeline
    auto pipeline = std::make_shared<dai::Pipeline>();
    // Define a source - color camera
    auto camRgb = pipeline->create<dai::node::ColorCamera>();

    camRgb->setPreviewSize(300, 300);
    camRgb->setBoardSocket(dai::CameraBoardSocket::CAM_A);
    camRgb->setResolution(dai::ColorCameraProperties::SensorResolution::THE_1080_P);
    camRgb->setInterleaved(false);

    // Create output
    auto xoutRgb = pipeline->create<dai::node::XLinkOut>();
    xoutRgb->setStreamName("rgb");
    camRgb->preview.link(xoutRgb->input);

    return pipeline;
}

int main(int argc, char** argv) {
    auto deviceInfoVec = dai::Device::getAllAvailableDevices();
    const auto usbSpeed = dai::UsbSpeed::SUPER;
    auto openVinoVersion = dai::OpenVINO::Version::VERSION_2021_4;

    std::map<std::string, std::shared_ptr<dai::DataOutputQueue>> qRgbMap;
    std::vector<std::shared_ptr<dai::Device>> devices;

    for(auto& deviceInfo : deviceInfoVec) {
        auto device = std::make_shared<dai::Device>(openVinoVersion, deviceInfo, usbSpeed);
        devices.push_back(device);
        std::cout << "===Connected to " << deviceInfo.getMxId() << std::endl;
        auto mxId = device->getMxId();
        auto cameras = device->getConnectedCameras();
        auto usbSpeed = device->getUsbSpeed();
        auto eepromData = device->readCalibration2().getEepromData();
        std::cout << "   >>> MXID:" << mxId << std::endl;
        std::cout << "   >>> Num of cameras:" << cameras.size() << std::endl;
        std::cout << "   >>> USB speed:" << usbSpeed << std::endl;
        if(eepromData.boardName != "") {
            std::cout << "   >>> Board name:" << eepromData.boardName << std::endl;
        }
        if(eepromData.productName != "") {
            std::cout << "   >>> Product name:" << eepromData.productName << std::endl;
        }
        auto pipeline = createPipeline();
        device->startPipeline(*pipeline);

        auto qRgb = device->getOutputQueue("rgb", 4, false);
        std::string streamName = "rgb-" + eepromData.productName + mxId;
        qRgbMap.insert({streamName, qRgb});
    }
    while(true) {
        for(auto& element : qRgbMap) {
            auto qRgb = element.second;
            auto streamName = element.first;
            auto inRgb = qRgb->tryGet<dai::ImgFrame>();
            if(inRgb != nullptr) {
                cv::imshow(streamName, inRgb->getCvFrame());
            }
        }

        int key = cv::waitKey(1);
        if(key == 'q' || key == 'Q') {
            return 0;
        }
    }
    return 0;
}
```

## 管道

### examples/multiple_devices.pipeline.json

```json
{
  "pipeline": {
    "connections": [
      {
        "node1Id": 0,
        "node1Output": "preview",
        "node1OutputGroup": "",
        "node2Id": 1,
        "node2Input": "in",
        "node2InputGroup": ""
      }
    ],
    "globalProperties": {
      "calibData": null,
      "cameraTuningBlobSize": null,
      "cameraTuningBlobUri": "",
      "leonCssFrequencyHz": 700000000.0,
      "leonMssFrequencyHz": 700000000.0,
      "pipelineName": null,
      "pipelineVersion": null,
      "sippBufferSize": 18432,
      "sippDmaBufferSize": 16384,
      "xlinkChunkSize": -1
    },
    "nodes": [
      [
        0,
        {
          "id": 0,
          "ioInfo": [
            [
              [
                "",
                "inputConfig"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 1,
                "name": "inputConfig",
                "queueSize": 8,
                "type": 3,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "raw"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 6,
                "name": "raw",
                "queueSize": 8,
                "type": 0,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "still"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 7,
                "name": "still",
                "queueSize": 8,
                "type": 0,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "inputControl"
              ],
              {
                "blocking": true,
                "group": "",
                "id": 2,
                "name": "inputControl",
                "queueSize": 8,
                "type": 3,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "video"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 3,
                "name": "video",
                "queueSize": 8,
                "type": 0,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "isp"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 4,
                "name": "isp",
                "queueSize": 8,
                "type": 0,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "preview"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 5,
                "name": "preview",
                "queueSize": 8,
                "type": 0,
                "waitForMessage": false
              }
            ],
            [
              [
                "",
                "frameEvent"
              ],
              {
                "blocking": false,
                "group": "",
                "id": 8,
                "name": "frameEvent",
                "queueSize": 8,
                "type": 0,
                "waitForMessage": false
              }
            ]
          ],
          "name": "ColorCamera",
          "properties": {
            "boardSocket": 0,
            "cameraName": "",
            "colorOrder": 0,
            "fp16": false,
            "fps": 30.0,
            "imageOrientation": -1,
            "initialControl": {
              "aeLockMode": false,
              "aeMaxExposureTimeUs": 0,
              "aeRegion": {
                "height": 0,
                "priority": 0,
                "width": 0,
                "x": 0,
                "y": 0
              },
              "afRegion": {
                "height": 0,
                "priority": 0,
                "width": 0,
                "x": 0,
                "y": 0
              },
              "antiBandingMode": 0,
              "autoFocusMode": 3,
              "awbLockMode": false,
              "awbMode": 0,
              "brightness": 0,
              "captureIntent": 0,
              "chromaDenoise": 0,
              "cmdMask": 0,
              "contrast": 0,
              "controlMode": 0,
              "effectMode": 0,
              "expCompensation": 0,
              "expManual": {
                "exposureTimeUs": 0,
                "frameDurationUs": 0,
                "sensitivityIso": 0
              },
              "frameSyncMode": 0,
              "lensPosAutoInfinity": 0,
              "lensPosAutoMacro": 0,
              "lensPosition": 0,
              "lensPositionRaw": 0.0,
              "lowPowerNumFramesBurst": 0,
              "lowPowerNumFramesDiscard": 0,
              "lumaDenoise": 0,
              "saturation": 0,
              "sceneMode": 0,
              "sharpness": 0,
              "strobeConfig": {
                "activeLevel": 0,
                "enable": 0,
                "gpioNumber": 0
              },
              "strobeTimings": {
                "durationUs": 0,
                "exposureBeginOffsetUs": 0,
                "exposureEndOffsetUs": 0
              },
              "wbColorTemp": 0
            },
            "interleaved": false,
            "isp3aFps": 0,
            "ispScale": {
              "horizDenominator": 0,
              "horizNumerator": 0,
              "vertDenominator": 0,
              "vertNumerator": 0
            },
            "numFramesPoolIsp": 3,
            "numFramesPoolPreview": 4,
            "numFramesPoolRaw": 3,
            "numFramesPoolStill": 4,
            "numFramesPoolVideo": 4,
            "previewHeight": 300,
            "previewKeepAspectRatio": true,
            "previewWidth": 300,
            "rawPacked": null,
            "resolution": 0,
            "sensorCropX": -1.0,
            "sensorCropY": -1.0,
            "stillHeight": -1,
            "stillWidth": -1,
            "videoHeight": -1,
            "videoWidth": -1
          }
        }
      ],
      [
        1,
        {
          "id": 1,
          "ioInfo": [
            [
              [
                "",
                "in"
              ],
              {
                "blocking": true,
                "group": "",
                "id": 9,
                "name": "in",
                "queueSize": 8,
                "type": 3,
                "waitForMessage": true
              }
            ]
          ],
          "name": "XLinkOut",
          "properties": {
            "maxFpsLimit": -1.0,
            "metadataOnly": false,
            "streamName": "rgb"
          }
        }
      ]
    ]
  }
}
```

### 需要帮助？

请前往 [OAKChina 官网](https://www.oakchina.cn/) 获取技术支持或解答您的任何疑问。