Why PSNR decreases for Ultrasound Images?

1. What does low PSNR mean?
2. What is a good PSNR value in image processing?
3. What is PSNR of an image?
4. What is the difference between SNR and PSNR?

What does low PSNR mean?

The PSNR block computes the peak signal-to-noise ratio, in decibels, between two images. This ratio is used as a quality measurement between the original and a compressed image. The higher the PSNR, the better the quality of the compressed, or reconstructed image.

What is a good PSNR value in image processing?

Typical values for the PSNR in lossy image and video compression are between 30 and 50 dB, provided the bit depth is 8 bits, where higher is better. The processing quality of 12-bit images is considered high when the PSNR value is 60 dB or higher. For 16-bit data typical values for the PSNR are between 60 and 80 dB.

What is PSNR of an image?

Peak signal-to-noise ratio (PSNR) is the ratio between the maximum possible power of an image and the power of corrupting noise that affects the quality of its representation. To estimate the PSNR of an image, it is necessary to compare that image to an ideal clean image with the maximum possible power.

What is the difference between SNR and PSNR?

SNR is defined relatieve to signal while PSNR is defined relative to peak dynamic range, i.e. 255 for an 8 bit image. SNR is badly defined for homogeneous images so for reconstruction evaluation often PSNR is preferred.