I first read an image with:
imread("imgFile.jpg", cv::IMREAD_UNCHANGED)
The image type is CV_8UC3.
After I convert the image into floats with
img.convertTo(f_img, CV_32FC1, 1/255.0);
When I use imshow for both images, they are both displayed with color.
imshow("Original Image", img); imshow("Converted Image", f_img);
This will both displayed as the same.