You can use OpenCV to easily and quickly apply a Sepia filter to your images, as seen in these pictures. Here is how:
First of all create a Kernel Matrix, like this:
cv::Mat kernel = (cv::Mat_<float>(3, 3) << 0.272, 0.534, 0.131, 0.349, 0.686, 0.168, 0.393, 0.769, 0.189);
Next, just apply this Kernel using transform OpenCV transform function to your image.
cv::transform(input_img, output_img, kernel);