将网络摄像头与yolov5型号一起使用

Question

我试图举办示例，但是我无法成功，因为执行命令行（image = cv2.imdecode（image，cv2.imread_color））时，代码正在返回无值。

1. 代码：

def infer():
    # Get the current image from the webcam
    ret, img = video.read()

    # Resize (while maintaining the aspect ratio) to improve speed and save bandwidth
    height, width, channels = img.shape
    scale = ROBOFLOW_SIZE / max(height, width)
    img = cv2.resize(img, (round(scale * width), round(scale * height)))

    # Encode image to base64 string
    retval, buffer = cv2.imencode('.jpg', img)
    img_str = base64.b64encode(buffer)

    # Get prediction from Roboflow Infer API
    resp = requests.post(upload_url, data=img_str, headers={
        "Content-Type": "application/x-www-form-urlencoded"
    }, stream=True).raw

    # Parse result image
    image = np.asarray(bytearray(resp.read()), dtype="uint8")
    image = cv2.imdecode(image, cv2.IMREAD_COLOR)
    
    return image

始终在IMDecode映像为数组之前，并非没有，Bellow显示了一个调试示例。

2. 但是

resp: <urllib3.response.HTTPResponse object at 0x0000015055DE7070>

image: array([ 11, 214,  13, ..., 170,   1,   3], dtype=uint8)

，当我运行cv2.imdecode（image，cv2.imread_color）时），我会获得图像的无值。

3. error

Exception has occurred: error OpenCV(4.6.0) D:\a\opencv-python\opencv-python\opencv\modules\imgcodecs\src\loadsave.cpp:816: 
error: (-215:Assertion failed) !buf.empty() in function 'cv::imdecode_'

  File "C:\Users\diego\codes\Webcam\infer-simple.py", line 48, in infer
    image = cv2.imdecode(image, cv2.IMREAD_COLOR)
  File "C:\Users\diego\codes\Webcam\infer-simple.py", line 63, in <module>
    image = infer()

我根据 https://blog.roboboflow.com/python---网络摄像头。

我应用了在互联网上找到的解决方案，还重新安装了所有必要的软件包，但没有任何效果。

Answer 1

问题不是从相机中获得图像，而是从服务器获得图像时。

您必须在Roboflow.com上创建项目，并获取Model的名称和API键 - 并使用所有这些来创建正确的URL。

我创建了带有名称国际样本cpuhx/1 的项目和受过训练的模型，并获得了API密钥，例如 TE7XXXXXXXXXXXX ，因此

https://detect.roboflow.com/chess-sample-cpuhx/1?format=image&stroke=5&api_key=tE7xxxxxxxxx

---

我的代码有几个更改。

我检查

• 网络摄像头是否给出了映像
• ，如果服务器发送响应状态 200 以及状态是否不同，请从服务器显示消息 - 例如 b'{“ message”：“ nt of condut”}'}'或 b'{“ message”：“ forbidden”}'

# all `import` at the beginning
import json
import base64
import cv2
import numpy as np
import requests
import time

# --- constants ---  

ROBOFLOW_API_KEY = 'tE7xxxxxxxxx'
ROBOFLOW_MODEL = 'chess-sample-cpuhx/1'
ROBOFLOW_SIZE = 400

# --- functions ---

params = {
    "api_key": ROBOFLOW_API_KEY,
    "format": "image",
    "stroke": "5"
}

headers = {
    "Content-Type": "application/x-www-form-urlencoded"
}

url = f"https://detect.roboflow.com/{ROBOFLOW_MODEL}"


def infer(img):
    # Resize (while maintaining the aspect ratio) to improve speed and save bandwidth
    height, width, channels = img.shape
    scale = ROBOFLOW_SIZE / max(height, width)
    img = cv2.resize(img, (round(scale * width), round(scale * height)))

    # Encode image to base64 string
    retval, buffer = cv2.imencode('.jpg', img)
    img_str = base64.b64encode(buffer)

    # Get prediction from Roboflow Infer API
    response = requests.post(url, params=params, data=img_str, headers=headers, stream=True)
    data = response.raw.read()
    
    #print(response.request.url)
    
    if not response.ok:
        print('status:', response.status_code)
        print('data:', data)
        return
    
    # Parse result image
    image = np.asarray(bytearray(data), dtype="uint8")
    image = cv2.imdecode(image, cv2.IMREAD_COLOR)

    return image

# --- main ---

video = cv2.VideoCapture(0)

while True:

    start = time.time()

    ret, img = video.read()
    
    if ret:
        
        image = infer(img)
        
        if image is not None:
            cv2.imshow('image', image)
        
            if cv2.waitKey(1) == ord('q'):  # `waitKey` should be after `imshow()` - to update image in window and to get key from window
                break
        
            end = time.time()
            print( 1/(end-start), "fps")  # print() automatically add space between elements - you don't need space in "fps"
        
# - end -

video.release()
cv2.destroyAllWindows()