Metrics for Stereoscopic Image Compression

Metrics for automatically predicting the compression settings for stereoscopic images, to minimize file size, while still maintaining an acceptable level of image quality are investigated. This research evaluates whether symmetric or asymmetric compression produces a better quality of stereoscopic image. Initially, how Peak Signal to Noise Ratio (PSNR) measures the quality of varyingly compressed stereoscopic image pairs was investigated. Two trials with human subjects, following the ITU-R BT.500-11 Double Stimulus Continuous Quality Scale (DSCQS) were undertaken to measure the quality of symmetric and asymmetric stereoscopic image compression. Computational models of the Human Visual System (HVS) were then investigated and a new stereoscopic image quality metric designed and implemented. The metric point matches regions of high spatial frequency between the left and right views of the stereo pair and accounts for HVS sensitivity to contrast and luminance changes in these regions. The PSNR results show that symmetric, as opposed to asymmetric stereo image compression, produces significantly better results. The human factors trial suggested that in general, symmetric compression of stereoscopic images should be used. The new metric, Stereo Band Limited Contrast, has been demonstrated as a better predictor of human image quality preference than PSNR and can be used to predict a perceptual threshold level for stereoscopic image compression. The threshold is the maximum compression that can be applied without the perceived image quality being altered. Overall, it is concluded that, symmetric, as opposed to asymmetric stereo image encoding, should be used for stereoscopic image compression. As PSNR measures of image quality are correctly criticized for correlating poorly with perceived visual quality, the new HVS based metric was developed. This metric produces a useful threshold to provide a practical starting point to decide the level of compression to use

P2_14 Shotgun patterns

This article provides a model of particle collisions for producing shot patterns from shotgun ammunition of a constant mass, for different numbers of pellets. The scatter pattern is found to be Gaussian, and the mean deviation for pellets from the centre increases linearly with range. Interestingly, this deviation is slightly greater for fewer large pellets, than the same mass of smaller pellets

P2_7 Power Curves and Gear Ratios in Bicycles

This article investigates how the power exerted by a cyclist varies with cyclist speed, and gear ratio. From Hill’s relation, both relations are determined and plotted. Suggestions are made on how these results might be useful to recreational and competitive cyclists

P2_4 Electromagnetic radiation from Mobile Phones

This paper demonstrates a method to quantify the energy absorbed by the human brain from using a mobile phone. Our results show the energy absorbed per second by a human head is PAbsorbed = 4.00 x 10-5 J.s-

P2_11 Fuselage Holes

This article looks at how long it would take the air to evacuate an aeroplane if the fuselage developed a hole, imposed under incompressible constraints. We find that the time for depressurisation, as a function of hole size, follows a linear, inverse power law. Â

P2_10 Shotgun!

This paper looks at the stopping power of shotguns as a function of distance from the target and number of shot in the shell.  This relationship is determined, and it is found that the stopping power falls off quickly for larger numbers of pellets. Avenues for a more thorough investigation are also suggested

P2_15 Quantum well widths as a function of doping

We iteratively calculate theoretical data within an infinite model, that allows you to determine the required well size given a specific doping, for a laser semiconductor emitting light between the wavelengths of 450 nm and 550 nm