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This is a good opportunity to educate the general [HN] community about dogs: 1. They can only see blue/yellow. Not like humans' RGB. 2. They are short sighted

by Joakal 7y ago

This is a good opportunity to educate the general [HN] community about dogs: 1. They can only see blue/yellow. Not like humans' RGB. 2. They are short sighted. For far away objects, their sight is like a T-Rex, they can see moving objects, not stationary objects. Remain still, and they can't see you. Then again, they can smell you, especially if it's downwind. 3. Their flicker fusion threshold is higher than humans. If you show them a cute mobile picture of a baby, they'll see a lot of flickering. As well, did you know lights have a flicker? If you think it's bad, it's even worse for dogs which can lead to stress. More: https://dog-vision.com/ https://dog-vision.com/ https://www.dogwalkersmelbourne.com.au/articles-dog-walking-pet-sitting/66-dog-canine-vision-seeing-compare-human.html https://www.dogwalkersmelbourne.com.au/articles-dog-walking-...

sl1ck731 7y ago
The flickering thing has always made me feel bad for my dog and dogs in general. My entire office room is monitors/TVs and I can only imagine what she sees, like a rave 24/7. But she will still sleep in here when she can go anywhere else in the house.
interfixus 7y ago
My 12 year old labrador is in excellent shape, but his hearing is no longer quite up to scratch, and to avoid embarrassing levels of shouting when we are out and about, I increasingly use pointing and other signs at my end of our communication. Also, his left eye has been problematic for many years, and apparently only registers the haziest of outlines these days. And yet, he contantly amazes me by the range and precision of his vision. Downwards pointing with my left arm means come here at once, which he will reliably register at a distance more than a hundred meters. Other dogs he will recognize at distances further than that, and he will unerringly home in on thrown stick bobbing on the water, as long as it's on the right, where his good eye can see. Clearly, there's more to it than just they are short sighted.
- dunstad 7y ago
  As a nearsighted human who didn't get glasses as early as he should have, I used to use people's gait or clothing to recognize them at long distances. You know your dog best, just saying there can be ways to compensate.
  - interfixus 7y ago
    Without a doubt, yes, all sorts of compensation are at play. Still, the fact remains that he reliably picks up my relatively subdued sign language at great distance. And swimming, even in rough sea, if he can't pick out the floating stick, he'll look to me, I'll point, he will scan as directed, and head straight for the thing. One way or the other, all this is decent visual performance, nothing nearsighted about it.
    - Moru 7y ago
      We all compensate for the handicaps we have. I'm also was very nearsighted since I was about 11. I did get glasses but didn't use them while skiing, not very confy under the helmet. But I could still see who of my classmates were at the bottom of the mountain, about 300 m away, because of the movement pattern. I have no clue how we know how dogs have bad eye sight, I can't even begin to imagine how we know about T-Rex. I have to look at that link someone posted.
- jacobush 7y ago
  I have noticed my dog scans people visually at a great distance. (Looking for people he might know, I imagine.)
miahi 7y ago
3. The flicker fusion issue mostly applies to cathode ray displays and moving pictures. Many LCDs use flickering light (PWM) for backlight, but usually at more than 200Hz. Better LCDs use linear current sources for backlight, so there's no flicker at all. An LCD should be fine even for dogs when static images are displayed.
- Frondo 7y ago
  Cheap LED bulbs actually flicker significantly, which I realized when I filmed using my camera's "slow motion" capture at 240 frames per second. In our bedroom, I put in some LEDs, not realizing there could possibly be a difference between cheap and expensive ones. One night I filmed my cat doing something dumb in slow motion, and when I looked at the playback the whole room was strobing. It was pretty wild. I might even still have the video, and could see about posting it somewhere.
  - Moru 7y ago
    You don't need slow motion camera, it's enough with most normal catch the worst offenders in the store if they have those led display sets where you can see the lightbulb lit. Just shove the camera real close to the lightbulb and watch the stripes. If no stripes, put it even closer (almost touching) and if it's still ok, buy it :-)
- quaa55 7y ago
  well now i’m curious, since we have a handful of LED bulbs throughout the house. they flicker no doubt, detectable through the slow motion setting on my phone camera. any suggestions on what energy efficient bulbs to replace them with?!
  - manmal 7y ago
    There are plenty of flicker free LEDs available, you just have to check beforehand. AFAIK all Philips LEDs are flicker free now, or at least those branded as “EyeCare”.
- deleted 7y ago
vanderZwan 7y ago
> As well, did you know lights have a flicker? If you think it's bad, it's even worse for dogs which can lead to stress. As someone who notices and gets really tired from the stroboscopic effects of cheap LEDs, I can only imagine how terrible that must be for dogs
- tw04 7y ago
  I'll take that over florescent any day of the week.
  - vanderZwan 7y ago
    Flickering fluorescent is soulsucking, I agree. Technically speaking, a similar kind of solution that exists for LEDs also exist for fluorescent tubes: using high frequency ballasts that do not perceptibly flicker (not even (near)subconsciously - which is true for a lot of LED and fluorescent lights). Those are more expensive, hard to find and not the default though.
- vectorEQ 7y ago
  try candles. natural light for me gives me least issues. most electric lights are exhausting...
  - vanderZwan 7y ago
    Incandescent light is generally better for the environment though (IIRC LowTechMagazine did the math for this)
  - atombender 7y ago
    Candles generate soot, which is not good for your health. The soot will also stain walls and ceilings, similar to cigarette smoke. Natural waxes like beeswax candles have a cleaner burn, but they're very expensive. If you're going to go non-electrical, I think an oil lamp (e.g. paraffin) is your best bet. Very cheap, safer than candles in the right lantern, and clean-burning (assuming a quality oil that doesn't have a lot of sulfur and other pollutants).
throwitaway9 7y ago
That's interesting. We switched to LED bulbs in our living room and after that our eldest dog would not settle, I thought maybe the bulbs had a low humming noise he didn't like but it could have been a flicker instead. We switched back and he was fine again.
- clairity 7y ago
  hmmm, the first 2 months of my (rescued) dog being in my home (a year ago) were anxiety-filled for her, and now i wonder if it was due to the led bulbs. she’s mostly settled now, realizing that home is good for sleep, though still gets nervous here and there. she likes being outside more but that seems to be true of dogs in general.
- WorldMaker 7y ago
  Or both. Some cheap LEDs have terrible high-pitched humming noises from bad AC to DC converters/transformers. (A big reason that there's a growing movement questioning if we should have more dedicated DC wires/plugs/sockets in our homes and do AC to DC conversion once for entire circuits instead at the socket/in the plug "wall wart" for every single device. Also interesting that USB A sockets are probably the closest we have to a ubiquitous home standard actually moving in that direction.)
  - 205guy 7y ago
    My wife was sensitive to the flickering of CFLs and LEDs running on AC, so we installed some dedicated 12V DC circuits in our house and they are really great. We run strings of DC LEDs from them, and they are bright and flicker-free. You can run the lights off of 12V batteries and charge those from a few solar panels, or just have one dedicated high-quality AC-DC transformer for the DC circuits.
Shivetya 7y ago
So, is fluorescent lighting in an area with dogs would be bad, or not? Is there method to determine which type of lighting is best? I expect even LED bulbs could flicker based on quality of the line. Am I wrong in assuming incandescent bulbs would be better
- ubercow13 7y ago
  LEDs can be very bad, depending on the circuitry, to the extent that it's uncomfortable for peoples. Incandescent bulbs won't flicker.
  - bitcurious 7y ago
    Incandescent bulbs flicker at the rate of the AC current, but the flickering is brighter/dimmer rather than on/off because they stay radiant while hot and cool slowly.
    - ubercow13 7y ago
      Yes but I guess the amplitude of the flicker must be very low? I'd have thought that if it was at all significant it would be very visually obvious at 50-60Hz
      - thfuran 7y ago
        It's really more like 120Hz since the polarity doesn't matter for incandescents.
        Moru 7y ago
        But you can stabilize the current quite nicely if you know how. This is almost never done on cheap LEDs. Except IKEA's leds, they were surpricingly good in some test lately.
b_tterc_p 7y ago
I don’t think T-Rexes actually suffered from that problem.
- Insanity 7y ago
  I think that was a "myth" indeed. But the OPs point is still valid. :)
  - ghostbrainalpha 7y ago
    https://www.iflscience.com/plants-and-animals/could-t-rex-really-only-see-you-if-you-moved/ https://www.iflscience.com/plants-and-animals/could-t-rex-re... Article has a couple of interesting points if people are wondering how we can actually know anything about T-Rex vision.
xsace 7y ago
today I learn dogs see us as Simpsons characters
lelima 7y ago
The dog Image Processing Tool is pretty awesome, thanks for the link! I wonder if is possible design glasses with the same goal.
sandworm101 7y ago
>>> Then again, they can smell you, especially if it's downwind. Only if the dog is downwind. Contrary to repeated myths about bears, no animal can air-scent objects downwind of themselves.
- saltcured 7y ago
  But, they might find your latent scent on the ground or on objects and follow that to you. So, being downwind at the moment is different from having a downwind approach to a new area...
sfaxon 7y ago
I actually got curious about this a year ago when I got a dog and she was watching me paint a wall. I made an iOS app* that allows you to see the color spectrum a dog sees, as well as take video and photos. Some weekend I hope to make enough time to add something to represent the short sightedness using image depth data as well as a few other features I would like to add. I actually had not heard about the flicker fusion threshold being different, thanks for the links! * https://itunes.apple.com/us/app/dog-optics/id1447069492?ls=1&mt=8 https://itunes.apple.com/us/app/dog-optics/id1447069492?ls=1...
stronglikedan 7y ago
I fully believe that they can also "see" scents, like a cartoon character floating to a pie on a window sill following a path of inhaled visible scent fumes, but I have no evidence of that.
hnick 7y ago
The funny thing with my dog, who we've done some scent work with, is that his nose seems to need to be focused and 'switched on' to really work. If I throw him a treat and he misses it, he will default to looking around with his eyes and missing it until I point it out. But give him the ready cue, and he can find a tiny piece of food or odour hidden in a drawer in a room in under a minute. So my take on that is it takes a lot of processing power to run the nose, and after a search session it's definitely nap time. And side note, I'd like to see AI efforts aiming at the level of a dog before we go for humans. It's amazing what they can do but it takes so long to train them and you have to start from scratch each time.

by Joakal 7y ago

sl1ck731 7y ago

The flickering thing has always made me feel bad for my dog and dogs in general. My entire office room is monitors/TVs and I can only imagine what she sees, like a rave 24/7. But she will still sleep in here when she can go anywhere else in the house.

interfixus 7y ago

My 12 year old labrador is in excellent shape, but his hearing is no longer quite up to scratch, and to avoid embarrassing levels of shouting when we are out and about, I increasingly use pointing and other signs at my end of our communication. Also, his left eye has been problematic for many years, and apparently only registers the haziest of outlines these days. And yet, he contantly amazes me by the range and precision of his vision. Downwards pointing with my left arm means come here at once, which he will reliably register at a distance more than a hundred meters. Other dogs he will recognize at distances further than that, and he will unerringly home in on thrown stick bobbing on the water, as long as it's on the right, where his good eye can see. Clearly, there's more to it than just they are short sighted.

dunstad 7y ago
As a nearsighted human who didn't get glasses as early as he should have, I used to use people's gait or clothing to recognize them at long distances. You know your dog best, just saying there can be ways to compensate.
- interfixus 7y ago
  Without a doubt, yes, all sorts of compensation are at play. Still, the fact remains that he reliably picks up my relatively subdued sign language at great distance. And swimming, even in rough sea, if he can't pick out the floating stick, he'll look to me, I'll point, he will scan as directed, and head straight for the thing. One way or the other, all this is decent visual performance, nothing nearsighted about it.
  - Moru 7y ago
    We all compensate for the handicaps we have. I'm also was very nearsighted since I was about 11. I did get glasses but didn't use them while skiing, not very confy under the helmet. But I could still see who of my classmates were at the bottom of the mountain, about 300 m away, because of the movement pattern. I have no clue how we know how dogs have bad eye sight, I can't even begin to imagine how we know about T-Rex. I have to look at that link someone posted.
jacobush 7y ago
I have noticed my dog scans people visually at a great distance. (Looking for people he might know, I imagine.)

miahi 7y ago

3. The flicker fusion issue mostly applies to cathode ray displays and moving pictures. Many LCDs use flickering light (PWM) for backlight, but usually at more than 200Hz. Better LCDs use linear current sources for backlight, so there's no flicker at all. An LCD should be fine even for dogs when static images are displayed.

Frondo 7y ago
Cheap LED bulbs actually flicker significantly, which I realized when I filmed using my camera's "slow motion" capture at 240 frames per second. In our bedroom, I put in some LEDs, not realizing there could possibly be a difference between cheap and expensive ones. One night I filmed my cat doing something dumb in slow motion, and when I looked at the playback the whole room was strobing. It was pretty wild. I might even still have the video, and could see about posting it somewhere.
- Moru 7y ago
  You don't need slow motion camera, it's enough with most normal catch the worst offenders in the store if they have those led display sets where you can see the lightbulb lit. Just shove the camera real close to the lightbulb and watch the stripes. If no stripes, put it even closer (almost touching) and if it's still ok, buy it :-)
quaa55 7y ago
well now i’m curious, since we have a handful of LED bulbs throughout the house. they flicker no doubt, detectable through the slow motion setting on my phone camera. any suggestions on what energy efficient bulbs to replace them with?!
- manmal 7y ago
  There are plenty of flicker free LEDs available, you just have to check beforehand. AFAIK all Philips LEDs are flicker free now, or at least those branded as “EyeCare”.
deleted 7y ago

vanderZwan 7y ago

> As well, did you know lights have a flicker? If you think it's bad, it's even worse for dogs which can lead to stress. As someone who notices and gets really tired from the stroboscopic effects of cheap LEDs, I can only imagine how terrible that must be for dogs

tw04 7y ago
I'll take that over florescent any day of the week.
- vanderZwan 7y ago
  Flickering fluorescent is soulsucking, I agree. Technically speaking, a similar kind of solution that exists for LEDs also exist for fluorescent tubes: using high frequency ballasts that do not perceptibly flicker (not even (near)subconsciously - which is true for a lot of LED and fluorescent lights). Those are more expensive, hard to find and not the default though.
vectorEQ 7y ago
try candles. natural light for me gives me least issues. most electric lights are exhausting...
- vanderZwan 7y ago
  Incandescent light is generally better for the environment though (IIRC LowTechMagazine did the math for this)
- atombender 7y ago
  Candles generate soot, which is not good for your health. The soot will also stain walls and ceilings, similar to cigarette smoke. Natural waxes like beeswax candles have a cleaner burn, but they're very expensive. If you're going to go non-electrical, I think an oil lamp (e.g. paraffin) is your best bet. Very cheap, safer than candles in the right lantern, and clean-burning (assuming a quality oil that doesn't have a lot of sulfur and other pollutants).

throwitaway9 7y ago

That's interesting. We switched to LED bulbs in our living room and after that our eldest dog would not settle, I thought maybe the bulbs had a low humming noise he didn't like but it could have been a flicker instead. We switched back and he was fine again.

clairity 7y ago
hmmm, the first 2 months of my (rescued) dog being in my home (a year ago) were anxiety-filled for her, and now i wonder if it was due to the led bulbs. she’s mostly settled now, realizing that home is good for sleep, though still gets nervous here and there. she likes being outside more but that seems to be true of dogs in general.
WorldMaker 7y ago
Or both. Some cheap LEDs have terrible high-pitched humming noises from bad AC to DC converters/transformers. (A big reason that there's a growing movement questioning if we should have more dedicated DC wires/plugs/sockets in our homes and do AC to DC conversion once for entire circuits instead at the socket/in the plug "wall wart" for every single device. Also interesting that USB A sockets are probably the closest we have to a ubiquitous home standard actually moving in that direction.)
- 205guy 7y ago
  My wife was sensitive to the flickering of CFLs and LEDs running on AC, so we installed some dedicated 12V DC circuits in our house and they are really great. We run strings of DC LEDs from them, and they are bright and flicker-free. You can run the lights off of 12V batteries and charge those from a few solar panels, or just have one dedicated high-quality AC-DC transformer for the DC circuits.

Shivetya 7y ago

So, is fluorescent lighting in an area with dogs would be bad, or not? Is there method to determine which type of lighting is best? I expect even LED bulbs could flicker based on quality of the line. Am I wrong in assuming incandescent bulbs would be better

ubercow13 7y ago
LEDs can be very bad, depending on the circuitry, to the extent that it's uncomfortable for peoples. Incandescent bulbs won't flicker.
- bitcurious 7y ago
  Incandescent bulbs flicker at the rate of the AC current, but the flickering is brighter/dimmer rather than on/off because they stay radiant while hot and cool slowly.
  - ubercow13 7y ago
    Yes but I guess the amplitude of the flicker must be very low? I'd have thought that if it was at all significant it would be very visually obvious at 50-60Hz
    - thfuran 7y ago
      It's really more like 120Hz since the polarity doesn't matter for incandescents.
      - Moru 7y ago
        But you can stabilize the current quite nicely if you know how. This is almost never done on cheap LEDs. Except IKEA's leds, they were surpricingly good in some test lately.

b_tterc_p 7y ago

I don’t think T-Rexes actually suffered from that problem.

Insanity 7y ago
I think that was a "myth" indeed. But the OPs point is still valid. :)
- ghostbrainalpha 7y ago
  https://www.iflscience.com/plants-and-animals/could-t-rex-really-only-see-you-if-you-moved/ https://www.iflscience.com/plants-and-animals/could-t-rex-re... Article has a couple of interesting points if people are wondering how we can actually know anything about T-Rex vision.

xsace 7y ago

today I learn dogs see us as Simpsons characters

lelima 7y ago

The dog Image Processing Tool is pretty awesome, thanks for the link! I wonder if is possible design glasses with the same goal.

sandworm101 7y ago

>>> Then again, they can smell you, especially if it's downwind. Only if the dog is downwind. Contrary to repeated myths about bears, no animal can air-scent objects downwind of themselves.

saltcured 7y ago
But, they might find your latent scent on the ground or on objects and follow that to you. So, being downwind at the moment is different from having a downwind approach to a new area...

sfaxon 7y ago

I actually got curious about this a year ago when I got a dog and she was watching me paint a wall. I made an iOS app* that allows you to see the color spectrum a dog sees, as well as take video and photos. Some weekend I hope to make enough time to add something to represent the short sightedness using image depth data as well as a few other features I would like to add. I actually had not heard about the flicker fusion threshold being different, thanks for the links! * https://itunes.apple.com/us/app/dog-optics/id1447069492?ls=1&mt=8 https://itunes.apple.com/us/app/dog-optics/id1447069492?ls=1...

stronglikedan 7y ago

I fully believe that they can also "see" scents, like a cartoon character floating to a pie on a window sill following a path of inhaled visible scent fumes, but I have no evidence of that.

hnick 7y ago

The funny thing with my dog, who we've done some scent work with, is that his nose seems to need to be focused and 'switched on' to really work. If I throw him a treat and he misses it, he will default to looking around with his eyes and missing it until I point it out. But give him the ready cue, and he can find a tiny piece of food or odour hidden in a drawer in a room in under a minute. So my take on that is it takes a lot of processing power to run the nose, and after a search session it's definitely nap time. And side note, I'd like to see AI efforts aiming at the level of a dog before we go for humans. It's amazing what they can do but it takes so long to train them and you have to start from scratch each time.