Interaction of image noise, spatial resolution, and low contrast fine detail preservation in digital image processing

We present a method to improve the validity of noise and resolution measurements on digital cameras. If non-linear adaptive noise reduction is part of the signal processing in the camera, the measurement results for image noise and spatial resolution can be good, while the image quality is low due to the loss of fine details and a watercolor like appearance of the image. To improve the correlation between objective measurement and subjective image quality we propose to supplement the standard test methods with an additional measurement of the texture preserving capabilities of the camera. The proposed method uses a test target showing white Gaussian noise. The camera under test reproduces this target and the image is analyzed. We propose to use the kurtosis of the derivative of the image as a metric for the texture preservation of the camera. Kurtosis is a statistical measure for the closeness of a distribution compared to the Gaussian distribution. It can be shown, that the distribut...

• Type: Journal
• Year: 2009
• Where: DPHOTO
• Authors: Uwe Artmann, Dietmar Wueller
• Keywords: Camera, DPHOTO 2009, Hardware, Image, Measurement