使用pytesseract处理手机截图PNG时出现OpenCV TypeError错误求助

原代码 #

img = cv2.imread('test.png',cv2.COLOR_BGR2GRAY)
custom_config = r'--oem 3 --psm 6'
data=pytesseract.image_to_string(img, config=custom_config)
print(data)

错误信息 #

Traceback (most recent call last):
 File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/PIL/Image.py", 
 line 2992, in fromarray
 mode, rawmode = _fromarray_typemap[typekey]
 KeyError: ((1, 1, 3), '<u2')

 The above exception was the direct cause of the following exception:

 Traceback (most recent call last):
 File "/home/hkc/Documents/work/opencv/test.py", line 13, in <module>
 data=pytesseract.image_to_string(img, config=custom_config)
 File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/pytesseract/pytesseract.py", line 423, in image_to_string
 return {
 File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/pytesseract/pytesseract.py", line 426, in <lambda>
 Output.STRING: lambda: run_and_get_output(*args),
 File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/pytesseract/pytesseract.py", line 277, in run_and_get_output
 with save(image) as (temp_name, input_filename):
 File "/usr/lib/python3.10/contextlib.py", line 135, in __enter__
 return next(self.gen)
 File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/pytesseract/pytesseract.py", line 197, in save
 image, extension = prepare(image)
 File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/pytesseract/pytesseract.py", line 171, in prepare
image = Image.fromarray(image)
File "/home/hkc/Documents/work/opencv/cv/lib/python3.10/site-packages/PIL/Image.py", 
line 2994, in fromarray
 raise TypeError("Cannot handle this data type: %s, %s" % typekey) from e
TypeError: Cannot handle this data type: (1, 1, 3), <u2

错误原因 #

1. 读取参数错误：cv2.imread的第二个参数应为读取模式，你误用了色彩转换常量cv2.COLOR_BGR2GRAY，导致图像读取格式异常。
2. 数据类型不兼容：部分手机截图PNG是16位色深（<u2代表无符号16位整数），而PIL的Image.fromarray无法直接处理该格式，pytesseract依赖PIL处理图像时触发错误。

修复代码 #

方案一：直接读取灰度图并处理16位图像 #

import cv2
import pytesseract

# 用正确的灰度模式读取图像
img = cv2.imread('test.png', cv2.IMREAD_GRAYSCALE)
# 判断是否为16位图像，转换为8位适配PIL
if img.dtype == 'uint16':
    img = cv2.normalize(img, None, 0, 255, cv2.NORM_MINMAX, dtype=cv2.CV_8U)

custom_config = r'--oem 3 --psm 6'
data = pytesseract.image_to_string(img, config=custom_config)
print(data)

方案二：读取彩色图后转灰度并处理16位图像 #

import cv2
import pytesseract

# 读取彩色图像
img = cv2.imread('test.png')
# 16位转8位
if img.dtype == 'uint16':
    img = cv2.normalize(img, None, 0, 255, cv2.NORM_MINMAX, dtype=cv2.CV_8U)
# 转换为灰度图
gray_img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

custom_config = r'--oem 3 --psm 6'
data = pytesseract.image_to_string(gray_img, config=custom_config)
print(data)

关键说明 #

• cv2.IMREAD_GRAYSCALE：正确的灰度图读取模式，确保输出单通道灰度图像。
• cv2.normalize：将16位图像的像素值范围（0-65535）映射到8位的0-255，让PIL能正常解析图像数据。

内容的提问来源于stack exchange，提问作者Hemant Kumar Chaudhary