Spectral Subtraction of Robot Motion Noise for Improved Event Detection in Tactile Acceleration Signals

New robots for teleoperation and autonomous manipulation are increasingly being equipped with high-bandwidth accelerometers for measuring the transient vibrational cues that occur during con- tact with objects. Unfortunately, the robot\u27s own internal mechanisms often generate significant high-frequency accelerations, which we term ego-vibrations. This paper presents an approach to characterizing and removing these signals from acceleration measurements. We adapt the audio processing technique of spectral subtraction over short time windows to remove the noise that is estimated to occur at the robot\u27s present joint velocities. Implementation for the wrist roll and gripper joints on a Willow Garage PR2 robot demonstrates that spectral subtraction significantly increases signal-to-noise ratio, which should improve vibrotactile event detection in both teleoperation and autonomous robotics

Optimal and acceptable white-point settings of a display

This study demonstrates that the preferred white-point for optimised colour rendering depends on image content. In general, people want to compensate for the average colour of the image, i.e. they choose a white-point that shifts the average colour towards a more neutral colour. The range of white-points that people tolerate was found to be extremely large. The region that was acceptable to 75% of the participants was about 0.04 wide along the daylight curve and about 0.02 perpendicular to the daylight curve (in terms of du'v'). The results suggest that, if one has to choose between the most common white-point settings of a TV, a white-point of 6500 K or 8700 K will be reasonable, whereas a white-point of 11000 K will be less optimal

Optimal and acceptable white-point settings of a display

This study demonstrates that the preferred white-point for optimised colour rendering depends on image content. In general, people want to compensate for the average colour of the image, i.e. they choose a white-point that shifts the average colour towards a more neutral colour. The range of white-points that people tolerate was found to be extremely large. The region that was acceptable to 75% of the participants was about 0.04 wide along the daylight curve and about 0.02 perpendicular to the daylight curve (in terms of du'v'). The results suggest that, if one has to choose between the most common white-point settings of a TV, a white-point of 6500 K or 8700 K will be reasonable, whereas a white-point of 11000 K will be less optimal

Optimal and acceptable white-point settings of a display

This study demonstrates that the preferred white-point for optimised colour rendering depends on image content. In general, people want to compensate for the average colour of the image, i.e. they choose a white-point that shifts the average colour towards a more neutral colour. The range of white-points that people tolerate was found to be extremely large. The region that was acceptable to 75% of the participants was about 0.04 wide along the daylight curve and about 0.02 perpendicular to the daylight curve (in terms of du'v'). The results suggest that, if one has to choose between the most common white-point settings of a TV, a white-point of 6500 K or 8700 K will be reasonable, whereas a white-point of 11000 K will be less optimal

<title>Influence of ambient illumination on adapted and optimal white point</title>

This study investigated the effect of the chromaticity and intensity of the ambient illumination on the adapted white point of a homogeneous image (i.e. the chromaticity that is perceived as achromatic) and on the optimal white point of natural images (i.e. the white point with the most preferred color rendering). It was found that the adapted white point and the optimal white point shift towards the chromaticity of the ambient illumination. The effect of illuminant color was approximately 2.5 times larger for the adapted white point than for the optimal white point. The intensity of the ambient illumination had no effect on the adapted white point and the optimal white point, except for images with face content. In agreement with previous studies, the optimal white point was found to strongly depend on image content. The results indicate that the optimal color rendering of natural images is a complex relation of image content and ambient illumination