Device To Simulate Motion

We want the motion to be constant - no acceleration, no deceleration. If the motion varies, it can spike or ebb bandwidth, it can make it harder to see if the frame rate drops, etc.

A ceiling fan

Dwayne, that's an interesting idea.

On the plus side for ceiling fans, they have a low setting where the fan moves slow enough that variances in frame rate could be detected. On the negative side, if we mount it on a ceiling, it would be awkward to test.

If there a way to mount a ceiling fan on a wall or pole. I know that basically makes it a table / floor stand but the problem with those is that they tend to run very fast, even at the lowest setting, like so:

Matt, thanks!

I think when fans oscillate, they decelerate when they reach the edges which could skew motion observation (i.e., the fan is moving slower at the edge than when it is moving past the center).

We could make the shutter much faster, and it is worth trying but I wonder how realistic the test is (i.e., we are testing cameras at fixed 1/1000 shutter which is not realistic in regular use).

I still think something with a single LBL would be your best bet - just enough to trigger recording without causing major changes in the scene. Find an old VCR for free on CL and don't set the clock on it :)

Btw, a manufacturer mentioned an interesting alternative approach - shifting / moving the cameras. While this does not deliver exact constant motion, it would allow us to control / replicate the motion in an indoor area. Since we mount cameras on a single tripod, we could simply swivel the arm back and forth, ensuring all cameras move at the same rate, at the same time looking at the same area.

John, I think it's not a good idea to test H.264 cameras with shifting / moving them. Moving object in camera field is better way to do it.

Cardboard box on a turntable. Comes in constant, repeatable 33 and 45rpm, the good ones even are adjustable. Decorate the four sides on the box with different test patterns, eye charts and mugshots. The distance to the camera determines field of view to be covered by moving object.

There are quite a number of good suggestions here - from analog clocks to stepper motors to an online stopwatch and a turntable.

Right now, I am most excited about the idea of the cardboard box on a turntable (presuming we can find one :). The turntable idea is interesting because it's 3 dimensional and moves at a constant rate of motion, which are 2 big pluses for testing motion. And unlike the stepper motor plus Arduino, it will work out of the box.

Keep the ideas coming and we will update as we try things out.

There's dozens of turntables on Amazon. I just need to figure out what is the best options for our needs. It appears there are 2 and 3 speed options.

Has a person been mentioned yet? That's the way we do it. One person watching and radioing to the person in the FOV. I am not sure any of these suggestions would actually in the field, how would you power them in hallway and set multiple zones with different sensitivities if you use a fixed device? Maybe I'm missing the point here.

Neither metronomes nor pendulum clocks give you constant motion.... they both swing back and forth - with faster speeds at the bottom of the 'swing', and slower speeds at the top of each swing.

They both measure time sequences... there isn't anything I know of that changes direction without changing speeds except for the little digital white 'ball' in Pong. :)

I like any spinning object where you can set (and maintain) various speeds.

So far, the turntable appears to be the most promising for our needs.

Hi John,

You're probably looking at combining a few things.

1) If you want to test motion blur / motion resolution: Attach an ISO line resolution chart to the moving piece. For instance pendulum/metronome, cardboard box on turntable, or train. The train may be better since the ISO chart will allow you to read out the horiz and vertical rez values. Putting the camera on the train allows you to capture a person.

2) If you want to test bandwidth / compression efficiency: The optimal motion test is to move the camera, or the whole test scene, sideways (Panning test). We mount the camera on a Lazy Susan type board, I guess some kind of motorized thingy can be devised. Set cameras to CBR and use line resolution chart, or measure with VBR and look at the bandwidth - in relation to the line resolution.

3) If you want to verify no dropped frames: Use stop watch with at least 1/30s resolution. Quite a few tenders have a requirement of no dropped frames, but we have also seen reputable 1080p30 spec cameras dropping frames when moving from a static scene to motion, or when motion becomes too complex, such as when doing PTZ.

4) We also use a small 'disco ball' with colored lights to spread random shadows and color in the scene.

A ceiling fan, with the blades removed; mounted to something lower than an actual ceiling.

Tie objects to the screw holes where the blades attach using a piece of string, with a length appropriate to keep the object within the frame of the cameras' view.

My first job was as a device to simulate constant motion. I'd walk around with a little walkie talkie to test if the burglar alarm PIRs picked up where they wanted to pick up.

If you can find a large floor fan that has a really slow speed, such as this guy, remove the cage, and glue colorful things such as playing cards or color charts to the blades, you should be able to simulate a moderately complex scene with constant motion.