2 research outputs found
RLFC: Random Access Light Field Compression using Key Views and Bounded Integer Encoding
We present a new hierarchical compression scheme for encoding light field
images (LFI) that is suitable for interactive rendering. Our method (RLFC)
exploits redundancies in the light field images by constructing a tree
structure. The top level (root) of the tree captures the common high-level
details across the LFI, and other levels (children) of the tree capture
specific low-level details of the LFI. Our decompressing algorithm corresponds
to tree traversal operations and gathers the values stored at different levels
of the tree. Furthermore, we use bounded integer sequence encoding which
provides random access and fast hardware decoding for compressing the blocks of
children of the tree. We have evaluated our method for 4D two-plane
parameterized light fields. The compression rates vary from 0.08 - 2.5 bits per
pixel (bpp), resulting in compression ratios of around 200:1 to 20:1 for a PSNR
quality of 40 to 50 dB. The decompression times for decoding the blocks of LFI
are 1 - 3 microseconds per channel on an NVIDIA GTX-960 and we can render new
views with a resolution of 512X512 at 200 fps. Our overall scheme is simple to
implement and involves only bit manipulations and integer arithmetic
operations.Comment: Accepted for publication at Symposium on Interactive 3D Graphics and
Games (I3D '19
Relationship between ventilatory function and age in master athletes and a sedentary reference population
Abstract Ageing is accompanied with a decline in
respiratory function. It is hypothesised that this may
be attenuated by high physical activity levels. We
performed spirometry in master athletes (71 women;
84 men; 35–86 years) and sedentary people (39 women;
45 men; 24–82 years), and calculated the predicted
lung age (PLA). The negative associations of age with
forced expiratory volume in 1 s (FEV1; 34 mL·year−1)
and other ventilatory parameters were similar in controls
and master athletes. FEV1pred was 9 % higher
(P<0.005) and PLA 15 % lower (P00.013) in athletes
than controls. There were no significant differences
between endurance and power athletes and sedentary
people in maximal inspiratory and expiratory pressure.
Neither age-graded performance nor weekly training
hours were significantly related to lung age. Life-long
exercise does not appear to attenuate the age-related
decrease in ventilatory function. The better respiratory
function in master athletes than age-matched sedentary
people might be due to self-selection and attrition bias