Curve-based and image-based JND contrast analysis for inverse tone mapping operators

Recent studies on inverse tone mapping attempt to reproduce real-world images using low dynamic range (LDR) images. Evaluation metrics to qualify the performance of inverse tone mapping operators (iTMOs) are important. Just Noticeable Difference (JND) is widely used in image analysis as visual sensitivity measure for quality assessment. However, this measure does not provide insights into how the characteristics of iTMO curves affect the quality of high dynamic range (HDR) images. Therefore, based on the probability of various contrast changes, this study proposes a curve-based and an image-based JND quality assessment metric to detect visual distortion. The results of this curve-based and image-based quality metric match those of the visible difference predictor (VDP) method. This metric does not require complex calibration and involves only simple computation. In addition, this method reveals the effect of various iTMO curve parameters.