NEW VISUAL PERCEPTUAL POOLING STRATEGY FOR IMAGE QUALITY ASSESSMENT

Most of Image Quality Assessment (IQA) metrics consist of two processes. In the first process, quality map of image is measured locally. In the second process, the last quality score is converted from the quality map by using the pooling strategy. The first process had been made effective and significant progresses, while the second process was always done in simple ways. In the second process of the pooling strategy, the optimal perceptual pooling weights should be determined and computed according to Human Visual System (HVS). Thus, a reliable spatial pooling mathematical model based on HVS is an important issue worthy of study. In this paper, a new Visual Perceptual Pooling Strategy (VPPS) for IQA is presented based on contrast sensitivity and luminance sensitivity of HVS. Experimental results with the LIVE database show that the visual perceptual weights, obtained by the proposed pooling strategy, can effectively and significantly improve the performances of the IQA metrics with Mean Structural SIMilarity (MSSIM) or Phase Quantization Code (PQC). It is confirmed that the proposed VPPS demonstrates promising results for improving the performances of existing IQA metrics.

The Secondary Motor Cortex-striatum Circuit Contributes to Suppressing Inappropriate Responses in Perceptual Decision Behavior

The secondary motor cortex(M2)encodes choice-related information and plays an important role in cue-guided actions.M2 neurons innervate the dorsal striatum(DS),which also contributes to decision-making behavior,yet how M2 modulates signals in the DS to influence perceptual decision-making is unclear.Using mice performing a visual Go/No-Go task,we showed that inactivating M2 projections to the DS impaired performance by increasing the false alarm(FA)rate to the reward-irrelevant No-Go stimulus.The choice signal of M2 neurons correlated with behavioral performance,and the inactivation of M2 neurons projecting to the DS reduced the choice signal in the DS.By measuring and manipulating the responses of direct or indirect pathway striatal neurons defined by M2 inputs,we found that the indirect pathway neurons exhibited a shorter response latency to the No-Go stimulus,and inactivating their early responses increased the FA rate.These results demonstrate that the M2-to-DS pathway is crucial for suppressing inappropriate responses in perceptual decision behavior.