View Full Version : Nighttime depth perception; any tricks?
12-21-2005, 09:47 PM
I know how to determine the distance and direction someone/something is moving by using a sword or other object, but I'm curious if there are any quick and easy methods for getting depth perception information at night?
I've tried using occlusion i.e. telephone poles at a distance, but it just doesn't seem to work very well, it's not really accurate. And raising your hand up to eye level, holding it there and standing still just looks a little weird- what if the person you're facing is coming toward you..
Just wonder about this because in Vancouver it gets dark at about 5pm now and crime is WAY up around here, so it's very important to have as much information about everything around you as possible. But I'd rather not look like a freak about it.
12-22-2005, 01:23 AM
Try riding a bike where it's uncrowded at night. If can get away with no lights, then do so. Also try doing the occasional waza with your eyes closed.
I don't think you will get much in the way of specifics when it's dark, such as being able to see details, but you can see the overall picture a bit better. You can notice movement really well. You can also get a better feel for movement at night as well. Have a training partner walk at you from different distances and also have them attack you from different distances to see what it is like and go from there.
12-22-2005, 07:59 AM
To follow on from what Brian said earlier. Using Togakure Ryu stance will help. Also adjusting your night vision will also be a skill along with hearing and feel for what is around you. One way to get a feel for night time is to go out with a friend from the dojo and that person drops you off. You have to walk at night withough a flashlite (unless there are dangerous snakes in your area then that will have some help) and walk 10 miles following a route on the map.
Make sure it crosses streams, rocky areas ETC. This will help in feeling that area around you for as you walk, the fround can become uneven, low branches can hit you. If you do this without a compass or GPS, you can get to point to point without having to use landmarks. You could make it even better if you have a few friends and they perform a mock attack when walking. This will also highten your awareness and pick out the fear of being attacked if you are not ready. This will also improve the silent walking method as well in case you think you may be attacked at that time.
So while out walking at night in the countryside, your perception of scale is reduced. When you havea mock attack, your perception of scale is reduced as the hidden part of the system comes into play. So not only are you walking and doing some night orenteering, but you are working on distance and a sort of sakki test as well.
12-22-2005, 11:18 AM
Never look directly at what ever your trying to judge. Look around it. Keep your eyes moving in a grid or circular pattern.
As was stated earlier, use your other senses to aquire data on your enviroment.
Have fun... :)
12-23-2005, 01:04 AM
What was mentioned about the Togakure Ryu stance is very important too. In the military you learn about night depth perception very quickly. We do most things from the ground, if you set up an ambush you are laying on the ground and while your enemy approaches he "could" be skylighted by his shape. Meaning his outline will be dark with the sky behind him or her. In motion some very good examples were given.
It's all in the hips and lower body, mine sucks BTW.
12-23-2005, 10:32 AM
You have received some good answers:
A small addition is knowing the exact distance of several objects !!
Irregardless of your method of acquiring the known distance,
Utilize some of the above mentioned techniques -
with different scenarios:
ie. walking upright , hunched over as a wrestler,
running , crawling , lying down and from above as in a tree;
[ use your imagination ].
It has been said it takes the rods in human eyes @ 20 minutes
to adjust to the night.
A red light does not cause harm to your sight...
If you continually scan the darkness , you will notice ambient light sources of varying degrees.
Without staring go from the darkest area to the lightest
area & search for the ambient light to assist you.
Each time you return your scan to the darkest area, your vision will have adjusted.
Feint lines and shapes will begin to appear.
Continue this scanning and searching till it meets your standard.
A superb reference for this knowledge is the "Australian Scout Manual".
Bujinkan Hontai Shibu
12-23-2005, 10:50 AM
The UK military use this book as reference:
A soldiers pocket book. You will find it halfway down the page. It not only covers fieldcraft, but night walking and night vision in the field.
And remember to close one eye should a bright source of light pop up (headlights of a car, as the most obvious example)!
12-26-2005, 06:17 AM
that only part works. I tried it on Salisbury Plain when I was there during my time in the Military. It takes half the time to come back but you are half blind to the night. If a light source is coming towards you, look away and close one eye. You will protect most of your night vision and not have those retina ghost type of lights in your vision.
But if you do get blinded while out walking/practicing, then you are too close and you have less of a chance of getting away, if you get the drift.
12-26-2005, 07:51 PM
Thanks for the responses, this is proving to be a most informative thread.
Let's use a particular scenario to brainstorm a few ideas.
You are walking down a lighted street, if the light from the streetlamps and houses weren't on, it'd be pretty dark if not completely black. The only color you can see on this person is the sort of yellowy-orange that streetlights cast on them. You have no stereo vision here to help you out.
In front of you on the sidewalk is a person. Judging by the apparent size of them they are at least 150 feet away. But as you are walking you cannot tell whether or not they are heading towards you.
Keeping an eye on them, you don't notice any indications of their direction- you can't see the fronts of their shoes, or any details on their jacket such as a zipper. All you can see is that they are moving, and they're either coming toward you or walking the same way as you.
Due to the motion caused by walking (even if walking very smoothly) it's nearly impossible to tell if their 'profile' is increasing or decreasing. All you can see is a person.
How do you determine if this person is heading towards you or away from you in such a case, without alarming them or other people that may be near you?
Holding your hand up in front of your eyes and just stopping works every time, but if that person is a bad guy and sees you doing this, it's going to spook them. Likewise if any 'innocent' people are around you it will just creep them out.
For the sake of this scenario, let's say you are unfamiliar with the area, this is the first time you've been in it, you've never seen it in daytime so you can't judge or remember how far objects are and then compare distances.
What do you do?
12-27-2005, 12:21 AM
i'd say i stop for a while, look for a landmark directly on the side of the path and gauge its distance, move a little to the side, and see if he passes it.
or you can always cross the street and view from an angle.
12-27-2005, 08:18 AM
Look at the legs and arms. Both bend forward so if the arm moves up and out of sight, you can assume they are moving away. Use a point marker system of 3 points and use point to point distance. Point one is where they are, point two nearer and point 3 futher away. If it is between point 3 and 3 then either the poerson is moving away or is going in circles. If the person moves into point one and seems to be getting nearer, then they will be.
On a dim street with lights intermittently spread, they can be your markers. So a quick judge can help in that way.
12-27-2005, 09:19 AM
Have you tried a railroad track? They have a standard measurement in small increments. Judge what is next to the track based on these measurements. If you get used to this then you should be able to do it without the tracks later.
All you need is a tape measure or rolling ruler. Also, smoke bombs. Can never go wrong with more smoke bombs. :)
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