报错如何解决，Exception in Tkinter callback Traceback (most recent call last): File "C:\Users\86135\AppData\Local\Programs\Python\Python39\lib\tkinter\__init__.py", line 1892, in __call__ return self.func(*args) File "F:\pycharm\实验5\Demo5_2.py", line 38, in count_cells _, contours, _ = cv2.findContours(self.thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE) ValueError: not enough values to unpack (expected 3, got 2)

这个错误是因为cv2库在新的版本中，`cv2.findContours()`函数返回值的格式发生了改变。在旧版本中，返回值是3个，包括轮廓、层次结构和近似轮廓点。而在新版本中，返回值是2个，只包括轮廓和层次结构。

要解决这个错误，可以将代码中的3个变量都替换为2个变量，或者使用新版本cv2库的返回值。以下是两种方法的代码示例：

方法一：将3个变量都替换为2个变量

import cv2
import numpy as np
import tkinter as tk
from tkinter import filedialog

class CellCounter:
    def __init__(self):
        self.root = tk.Tk()
        self.root.title("Cell Counter")
        self.root.geometry("400x300")
        self.img = None
        self.thresh = None
        self.count = 0
        self.img_label = tk.Label(self.root, text="No image selected")
        self.img_label.pack(pady=10)
        self.btn_select = tk.Button(self.root, text="Select Image", command=self.select_image)
        self.btn_select.pack(pady=10)
        self.btn_count = tk.Button(self.root, text="Count Cells", command=self.count_cells)
        self.btn_count.pack(pady=10)
        self.count_label = tk.Label(self.root, text="Cell Count: 0")
        self.count_label.pack(pady=10)

    def select_image(self):
        path = filedialog.askopenfilename(filetypes=[("Image Files", "*.jpg;*.jpeg;*.png;*.bmp")])
        if path:
            self.img = cv2.imread(path)
            self.img_label.config(text="Image: {}".format(path))
            self.thresh = None
            self.count = 0
            self.count_label.config(text="Cell Count: 0")

    def count_cells(self):
        if self.img is None:
            return
        if self.thresh is None:
            gray = cv2.cvtColor(self.img, cv2.COLOR_BGR2GRAY)
            _, self.thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV+cv2.THRESH_OTSU)
        contours, _ = cv2.findContours(self.thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
        self.count = len(contours)
        self.count_label.config(text="Cell Count: {}".format(self.count))

    def run(self):
        self.root.mainloop()

if __name__ == "__main__":
    app = CellCounter()
    app.run()

方法二：使用新版本cv2库的返回值

import cv2
import numpy as np
import tkinter as tk
from tkinter import filedialog

class CellCounter:
    def __init__(self):
        self.root = tk.Tk()
        self.root.title("Cell Counter")
        self.root.geometry("400x300")
        self.img = None
        self.thresh = None
        self.count = 0
        self.img_label = tk.Label(self.root, text="No image selected")
        self.img_label.pack(pady=10)
        self.btn_select = tk.Button(self.root, text="Select Image", command=self.select_image)
        self.btn_select.pack(pady=10)
        self.btn_count = tk.Button(self.root, text="Count Cells", command=self.count_cells)
        self.btn_count.pack(pady=10)
        self.count_label = tk.Label(self.root, text="Cell Count: 0")
        self.count_label.pack(pady=10)

    def select_image(self):
        path = filedialog.askopenfilename(filetypes=[("Image Files", "*.jpg;*.jpeg;*.png;*.bmp")])
        if path:
            self.img = cv2.imread(path)
            self.img_label.config(text="Image: {}".format(path))
            self.thresh = None
            self.count = 0
            self.count_label.config(text="Cell Count: 0")

    def count_cells(self):
        if self.img is None:
            return
        if self.thresh is None:
            gray = cv2.cvtColor(self.img, cv2.COLOR_BGR2GRAY)
            _, self.thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV+cv2.THRESH_OTSU)
        _, contours = cv2.findContours(self.thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
        self.count = len(contours)
        self.count_label.config(text="Cell Count: {}".format(self.count))

    def run(self):
        self.root.mainloop()

if __name__ == "__main__":
    app = CellCounter()
    app.run()

希望这些方法可以帮助你解决报错问题！