Image panr

Peak signal to noise ratio （ English ：Peak signal-to-noise ratio, Often abbreviated to PSNR） It is an engineering term that represents the ratio of the maximum possible power of a signal to the destructive noise power that affects its representation accuracy . Because many signals have a very wide dynamic range , The peak signal-to-noise ratio is usually expressed in logarithmic decibel units .

The meaning of numerical value

The typical peak signal-to-noise ratio in image and image compression is 30dB To 50dB Between , The higher the better .

• PSNR near 50dB , Represents that the compressed image has only a very small error .
• PSNR Greater than 30dB , It is difficult for the human eye to detect the difference between the compressed image and the original image .
• PSNR Be situated between 20dB To 30dB Between , The human eye can detect the difference in the image .
• PSNR Be situated between 10dB To 20dB Between , The human eye can still see the original structure of the image with the naked eye , And it can be intuitively judged that there is no great difference between the two images .
• PSNR lower than 10dB, It is difficult for humans to judge whether two images are the same with the naked eye , Whether one image is the compression result of another image .

Original image without deliberate compression

 

PSNR 47.61dB

 

PSNR 34.02dB

 

PSNR 24.46dB

 

With different compression ratio PSNR Compare （ Click on the picture to enlarge ） The picture shows the tarmac of Taiwan Taoyuan International Airport

application

Peak signal to noise ratio (PSNR) is often used to measure the quality of signal reconstruction in the field of image compression in image processing ,