Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Walkway South View – Sony HDR-AS30V still image – detail
The thing has absolutely no affordance for hand-holding, so perching it on the Walkway handrail 200 feet over the Hudson required tamping down my usual risk aversion.
Both images have been slightly contrast-tweaked and lightly compressed from the original data, but not by enough to matter here. Generally, I apply ruthless compression to keep the image size under control, so these look a lot better than the usual pix around here.
Entering Rt 376 from Diddell Road after leaving the Dutchess Rail Trail:
Rt 376 – Diddell to New Hackensack – 1
All of Rt 376 has thick gravel along the shoulder from the deteriorating asphalt.
The wheel-trapping longitudinal cracks on the shoulder show where the previous surface extended beyond the bottom paving layer. Basically, you must ride to the right of the edge of the “new” cap over the travel lane and left of the parallel cracks:
Rt 376 – Diddell to New Hackensack – 2
Sometimes, you must use the road surface. Fortunately, it’s not too bad at this spot:
Rt 376 – Diddell to New Hackensack – 3
But it quickly returns to normal:
Rt 376 – Diddell to New Hackensack – 4
In some places, the travel lane is developing longitudinal cracks, so moving off the shoulder will require taking the lane:
Rt 376 – Diddell to New Hackensack – 5
Chooosing your line requires the ability to ride precisely between gravel, cracks, and traffic:
Rt 376 – Diddell to New Hackensack – 6
I can ride along this plateau every time, but it seems unreasonable to expect that level of ability from every bicyclist:
Rt 376 – Diddell to New Hackensack – 7
In this spot, the potholes expose three layers of paving. The only “safe” line seems to be on the very edge of the “new” cap, just to the right of the potholes:
Rt 376 – Diddell to New Hackensack – 8
The “new” cap didn’t adhere to the previous asphalt very well, perhaps because the thickness dropped below the spec. I’m crossing the travel lane to reach the left turn storage lane at the New Hackensack signal, having avoided a drain grate that occupies the ever-narrowing shoulder:
Rt 376 – Diddell to New Hackensack – 9
A map showing the route:
Rt 376 – Diddell to New Hackensack – map
[Edit: A comment from someone who shall remain anonymous:
This person has found an amusing way to get attention to potholes: he just adds a penis drawing to the pothole with spray paint.
The parameter order matters: the -ss must come before the -i input file name and the -t must come after it. Otherwise, avconv will copy the entire file before extracting the clip, which can be tedious.
The Fly6 camera produced a video file containing ten minutes of variations on this theme:
Fly6 – 0842001.AVI – Video compression failure
The top of the image looked pretty good, but then the decompression stalls and smears a single, slowly degenerating, line down the rest of the frame. The other files from that trip looked just fine.
As it turned out, extracting a few seconds with avconv or binary-copying the first few megabytes with dd produced playable copies: the original file tripped vlc’s decompression, but the source data was in the file and the copies worked.
Soooo, I could recover the video. Not that it was particularly important, but knowing how might matter some day.
Video is weird.
The Cycliq tech support folks recommend regularly formatting the MicroSD card using the Official SD Association Program (Windows-only, of course), not erasing any video files, and generally letting the camera handle the card. This whole affair seems remarkably fragile.
So I stuck a snippet of ordinary “transparent” (it’s actually translucent) adhesive tape across the top of the Cycliq Fly6 camera lens:
Cycliq Fly6 Camera – blur tape
That smoothly blurs the top third of the frame:
Fly6 – Tape-blurred frame
The motivation for using translucent tape: it should maintain roughly the same brightness and color balance across the whole image. Opaque tape would burn out the remaining image as the camera desperately tries to maintain an average gray level.
Fast-forwarding VLC with the video stopped forces it to display the inter-frame compression blocks spanning several seconds of video:
Fly6 – Forced compression artifacts
The upper third of the frame has big, simple blocks that pegged the files at a uniform 475 MB per ten minute file, somewhat lower than the un-blurred 500 to 700 MB. So the compression definitely isn’t working nearly as hard.
I hoped that simplifying the uninteresting part of the image would leave more bits for license plates and other interesting details, which might be the case. New York has two main licence plate color schemes (the obsolete high-contrast blue-on-white and the current low-contrast blue-on-orange “Empire Gold”) and both the Fly6 and the Sony AS30V cameras do much better with white plates in full sun.
Some samples at full size:
Fly6 – License Plates
Those were chosen based on:
Similar range / angle: just over the center line
Same-size crop box: 350 x 197
Sun vs. shade
I think those are somewhat sharper than the plates from un-blurred frames, but it’s not like the camera suddenly woke up smarter and started paying attention to the important stuff.
Just south of Lake Walton on the Dutchess Rail Trail, I encountered a barred owl with wings spread around something yummy in its talons (clicky for more dots):
MAH00389-0548 – Barred Owl on DCRT – 1
The owl acquired weapons lock on me, just in case I might try to steal its fresh-killed meal:
MAH00389-0548 – Barred Owl on DCRT – 2
My neck doesn’t turn nearly that far, so I lost the staring contest:
MAH00389-0548 – Barred Owl on DCRT – 3
Owls being good folks to have around, we wish ’em well: may they raise many owlets!
The pictures were extracted from the Sony HDR-AS30V helmet camera with this incantation:
The -q 1 parameter should produce an image with the same dots as the original, but that really doesn’t mean much in the face of the camera’s relentless video compression.
Here’s a dot-for-dot crop (at 100% JPEG quality = uncompressed) showing the tradeoff between wide field-of-view, detail, and compression:
MAH00389-0548 – Barred Owl on DCRT – 2 – detail
Makes me appreciate my eyesight: I spotted that owl when it covered just a few image pixels. Of course, at first I thought somebody dropped a hoodie on the trail, then maybe it was a chunk of debris, so I eased off the asphalt onto the gravel Just In Case.
We recently watched a gray squirrel drag a completely limp and unresponsive companion across the driveway, stopping every few yards to rest. We often see pairs of squirrels frisking / chasing / tussling in the yard, but this was something new.
After 100 feet of dragging, with pauses every few yards, the squirrel had hauled her companion to the fence at the far side of the yard. I leaped to the conclusion that the limp squirrel was dead:
Mother squirrel and pup – 1
But, after perhaps a minute, the “dead” squirrel gradually awoke and both critters slowly clambered up the fence. The squirrel on the right had been doing the dragging and is unquestionably female, the one on the left is much smaller and likely a new pup:
Mother squirrel and pup – 2
So apparently the mother squirrel had hauled one of her pups away from something. Perhaps it was stunned after falling out of a tree or the sole survivor of a hawk attack? We’ll never know The Rest of The Story.
Having recently mounted a Cycliq Fly6 rear-facing camera (more about this later) on my Tour Easy’s seat, I had high hopes it might produce more legible images than the Sony HDR-AS30V helmet camera. Although these still images have been compressed a bit, that doesn’t affect the conclusions; the video files aren’t any more readable.
The Fly6 shows where the driver laid on the horn:
Rt 376 at Cedar Valley – 2015-05-22 13:34 – Seat – 1
The next two come from the Sony HDR-AS30V helmet camera:
We couldn’t hear what the passenger said above the horn, but it didn’t sound friendly:
Rt 376 at Cedar Valley – 2015-05-22 13:34 – Helmet – 1
However, the driver gave us about as much clearance as can reasonably be expected with oncoming traffic:
Rt 376 at Cedar Valley – 2015-05-22 13:34 – Helmet – 2
Traffic generally hits the 40 mph = 60 ft/s speed limit on that curve and we’re rolling at 10 mph = 15 ft/s, so the relative motion might be upwards of 45 ft/s. The Fly6 runs at 30 frame/s = 1.5 ft and the AS30V at 60 frame/s = 0.75 ft. Although the exposure time is much shorter than the frame time, you can see plenty of motion blur in all the images.
The Fly 6 captures 1280×720 video @ 30 frame/s with variable bit rate compression, saving a separate file every 10 minutes on the dot. The files range from 300 MB to 600 MB, more or less.
The AS30V captures 1920×1080 @ 60 frame/s with constant bit rate compression, plopping a 4 GB file every 22 minutes and 43 seconds.
The Fly6 seems to preserve more image detail than the AS30V, but it’s probably a factor of the native resolution and compression method. The cameras provide absolutely no control over any image functions or settings; they do what they do and you get what you get.
The video compression algorithms seem overwhelmed by the number of pixels that change from frame to frame: asphalt and leaves generally have blocky compression artifacts, particularly in low light, and license plate text generally gets compressed into a blur.
When the camera remains stationary and the image doesn’t change, the compression artifacts largely disappear and the images become crisp and beautiful. Unfortunately, that’s not generally the situation while we’re riding.
I want to apply “low resolution OK here” masks to parts of the frame, leaving more bits for the critical parts. Perhaps applying thin tape to the top third of the frame would help?
Meanwhile, back on the road, nearly all drivers understand the rules and act accordingly; this was a rare occurrence.
The Smell of Molten Projects in the Morning 