使用cv2.resize()调整图像尺寸时遇(-215)错误的技术求助

Hey there! Let's sort out this frustrating OpenCV resize error—it's a common gotcha, but once you know the culprits, fixing it is straightforward. Here are the most likely reasons and how to fix them:

1. Your image didn't load correctly (the #1 cause) #

The error often pops up because test_image is None (meaning OpenCV couldn't read the file at all). This happens for a few reasons:

• Wrong file path (double-check relative vs absolute paths—if your script is in a different folder, the path might not be what you think)
• Corrupted image file (try opening the image in a viewer to confirm it's intact)
• Unsupported image format (OpenCV doesn't handle all rare formats)

Fix it with a quick check:

test_image = cv2.imread("your_image_file.jpg")
# Always verify the image loaded before processing
if test_image is None:
    print(f"Error: Couldn't load image! Check the path or file.")
    # Add logic to skip this file or exit gracefully
else:
    # Proceed with resize
    resized = cv2.resize(test_image, (272, 272))

2. Your target size is invalid #

The error message explicitly checks that both width and height are positive. Even if you wrote (272,272), make sure:

• You didn't accidentally pass a nested tuple like ((272,272)) (though OpenCV usually handles this, it's better to stick to a single tuple (272,272))
• You're not using variables for size that accidentally evaluate to 0 or a negative number (e.g., a calculation that went wrong)

Quick validation:

target_size = (272, 272)
if target_size[0] <= 0 or target_size[1] <= 0:
    print("Error: Target size must have positive width and height!")

3. The original image has an invalid size #

In rare cases, the image loads but has a 0x0 pixel size (super corrupted files might do this). Check the shape before resizing:

print(test_image.shape)  # Should output something like (480, 640, 3) for a valid color image
# If this throws an error, the image didn't load correctly

Working Example #

Here's a full, safe script that avoids the error:

import cv2

def resize_image(image_path, target_size=(272, 272)):
    # Load image
    img = cv2.imread(image_path)
    if img is None:
        print(f"Failed to load {image_path}")
        return None
    
    # Validate target size
    if target_size[0] <= 0 or target_size[1] <= 0:
        print(f"Invalid target size: {target_size}")
        return None
    
    # Resize and return
    resized_img = cv2.resize(img, target_size)
    print(f"Resized {image_path} from {img.shape[:2]} to {resized_img.shape[:2]}")
    return resized_img

# Usage
resized = resize_image("my_photo.jpg", (64, 64))
if resized is not None:
    cv2.imwrite("resized_photo.jpg", resized)

内容的提问来源于stack exchange，提问作者Paani