OpenCV Resize Error: 'Assertion failed' in cv::resize() - Fix and Example

This error message is generated by OpenCV when trying to resize an image using the 'cv::resize()' function. The error indicates that the input image size is empty, meaning that the image dimensions are not valid.

To fix this error, you need to ensure that the input image is not empty and has valid dimensions before calling the 'cv::resize()' function. You can check the image size using the 'cv::size()' function and make sure it is not empty.

Here is an example code snippet to demonstrate how to resize an image using OpenCV:

#include <opencv2/opencv.hpp>

int main() {
    // Read input image
    cv::Mat image = cv::imread('input.jpg');

    // Check if the image is empty
    if (image.empty()) {
        std::cout << 'Error: Failed to read image' << std::endl;
        return -1;
    }

    // Resize the image
    cv::Mat resizedImage;
    cv::resize(image, resizedImage, cv::Size(640, 480));

    // Display the resized image
    cv::imshow('Resized Image', resizedImage);
    cv::waitKey(0);

    return 0;
}

Make sure to replace 'input.jpg' with the path to your actual input image file.

By ensuring that the input image is not empty and has valid dimensions, you should be able to avoid the assertion failed error when using the 'cv::resize()' function in OpenCV.