New stealth technology? :D

[Nigel Goodwin]

OK, just as a matter of interest I stuck an SD card in a wireless CCTV camera I have knocking around, and pointed it at a dish of food we put out, mostly for the hedgehogs. We weren't sure actually what was eating the food.

We were quite surprised at the results - but amazed at how invisible hedgehogs are under IR - look at about 23:39 onwards.

http://www.lpilsley.co.uk/videos/Fox_Hedgehog2357.mp4

I can't say I'm overly impressed with the quality, so I've ordered a 'trail camera' from Amazon, arriving later today

 

[JimB]

Very interesting.

Several things stand out:
The high reflectivity of the fox eyes to IR light.
The fox seemed to look directly at the IR light as if it could actually see it.
As the hedgehog moved around, it seemed to leave a "trail" on the video.
Odd thought, is the hedgehog "hot" enough to warm the ground slightly as it shuffles along?

JimB

 

[Nigel Goodwin]

Very interesting.

Several things stand out:
The high reflectivity of the fox eyes to IR light.
The fox seemed to look directly at the IR light as if it could actually see it.

The various fox examples all seem to be able to see the IR, as do the numerous cats which also pass through (they also glare at the camera, in the way cats do). The hedgehogs eyes also reflect IR in a similar fashion.

At least none of them seem to be triggering the PIR light in the yard.

As the hedgehog moved around, it seemed to leave a "trail" on the video.
Odd thought, is the hedgehog "hot" enough to warm the ground slightly as it shuffles along?

I don't know?, weird isn't it

I presume the hedgehogs prickles scatter the IR, and perhaps prevent heat lose from it's body, no prickles underneath of course, so perhaps there's some degree of heat transfer to the ground?.

As for shuffling, they can be quite speedy as well.

It'll be interesting to see what it looks like on the new camera that's on it's way - had an email from Amazon, it's out for delivery, and (supposedly) due between 15:00 -18:00, although in my experience the estimated time usually slips throughout the day.

 

[Tony Stewart]

The visual ghost trails must have something to do with the recorder trigger algorithm for motion sensing and lack of motion detection timing as many visible high contrast black objects are grey under IR I have found from my tests and may serve as a good defense from aggressors with similar poor monochromatic IR vision .\

SNIP....

Animal eyes often appear to reflect light brightly in the dark due to a special layer of tissue called the tapetum lucidum. The tapetum lucidum is found behind the retina in the back of the eye and acts as a mirror-like structure.

When light enters the eye, it passes through the retina, where photoreceptor cells called rods and cones detect the light and send signals to the brain for visual processing. However, not all the light that enters the eye is absorbed by the photoreceptor cells. Some of the light that passes through the retina is reflected by the tapetum lucidum back through the retina, giving it a second chance to be detected.

The tapetum lucidum consists of layers of reflective cells that contain special pigments, such as guanine crystals or other reflective substances. These pigments effectively bounce the light back through the retina, increasing the chance of capturing more available light.

This reflective effect is particularly beneficial for animals that are active in low-light conditions or at night, such as nocturnal animals. By reflecting and amplifying the available light, the tapetum lucidum enhances their night vision and allows them to see more clearly in dimly lit environments.

The specific color of the eyeshine varies depending on the animal and the structure of the tapetum lucidum. Some animals, like cats, display a bright green or yellow eyeshine, while others may have an orange, blue, or white eyeshine.

It's important to note that not all animals possess a tapetum lucidum, and the intensity of eyeshine can vary among species. Animals with well-developed tapeta tend to exhibit more noticeable eyeshine in the dark.

 

[rjenkinsgb]

I suspect the odd hedgehog imagery is at least partly to do with the camera MPEG compression.

The grey colour it shows at is within the range of greys in the concrete? floor, so it's not getting enough frame to frame difference in those areas to reprocess them and instead re-using the little changed parts of the previous frames.

 

[Nigel Goodwin]

Well here's a video of the hedgehog from the new camera, not so stealthy on this one

http://www.lpilsley.co.uk/videos/11_June_2023/Hog1.mp4

 

[JimB]

Your back yard is a veritable Serengeti for wildlife.
Fox
Cat
Hedgehog
Assorted flying insects
and, a spider.

JimB

 

[Nigel Goodwin]

Your back yard is a veritable Serengeti for wildlife.
Fox
Cat
Hedgehog
Assorted flying insects
and, a spider.

JimB

I'd not noticed a spider

It's the number of times foxes pass through (there's at least two, as two once followed each other) that surprised me.

Cat's are obvious - we used to have cats, next door has a cat (Timmy - who we look after when they go away), and there are many cats up and down the street. Timmy gets in lot's of fights with trespassing cats

 

[JimB]

I'd not noticed a spider

At time 23:50:39, the spider goes from right to left up the picture half way between the time text and the bottom of the fence.

JimB

 

[Nigel Goodwin]

At time 23:50:39, the spider goes from right to left up the picture half way between the time text and the bottom of the fence.

JimB

Somebody's got good eyes!

It's not like it's a very substantial spider, thin legs and almost no body.

 

[rjenkinsgb]

not so stealthy on this one

That camera is vastly better than the other one, really nice quality!

 

[Nigel Goodwin]

That camera is vastly better than the other one, really nice quality!

It's 1080P resolution for video, the other CCTV camera only seemed to record in VGA resolution - you can monitor the camera in higher resolution, but it only saves VGA to the internal SD card.

Only snag is the new camera isn't WiFi, so you have to physically bring the camera inside to read the contents of the SD card (or you could just bring the card. It also runs off 8xAA batteries, or an external 6V supply (strange?, 12V of AA's or 6V?) - the external supply lead also ends in a USB plug (you can see it in the picture above), so you'd expect it to be 5V?.

Still, not a bad price at £39.95 and next day delivery