问题
I am wondering seriously about the effects of cv2.imwrite() function of OpenCV.
I noticed that when I read pictures with cv2.imread() and save them again with cv2.imwrite() function, their quality is not the same any more for the human eyes.
I ask you how can I keep the quality of the image the same as the original after saving it using cv2.imwrite() function.
I ask this question because I have really a serious issue in a larger program and when I checked the quality of the pictures saved by this function, I guesses that my problem comes certainly from this function.
For example, I draw using the mouse movements small red (Red=255) squares on picture . When I save the picture and count the number of pixels that have Red color equal to 255 I get very few of them only even if I draw a lot of them in pure red color. But when I check the image by my eyes, I notice the red pixels I drawed are not correctly saved in the correct red color I chosed (255).
Any one does know how to resolve this problem ? I mean to save the pictures using OpenCV without degrading its quality.
回答1:
JPEG is a lossy format, you need to save your images as PNG as it is a lossless format.
来源：https://stackoverflow.com/questions/28940711/not-losing-the-quality-of-pictures-saved-with-cv2-imwrite