Mocha for Aerials?


#1

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I think that some of the shapes are covering rocks that change “planes” too much when passed over. Might be better to focus on smaller patterned areas on that remain relatively flat when passed over.

If you have the time to post me the high res footage, that would be best.

I will be working tomorrow, but otherwise can get back to you next week.
Best
R
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#2

—Quote (Originally by ross_shain)—
Just to follow up on this thread. I played with this clip a bunch yesterday and determined that if you are trying to “smooth camera jitter” than I got best results by following the following steps:

  1. tracked a a few relatively small rock areas with 1 shape.
  2. turned off all track parameters except transform
  3. Once the shape was about to go offscreen, stop tracker and move to another rock area on same plane. Continue tracking.

To smooth stabilize, I used After Effects and the smoother to reduce the keyframes. This technique is detailed in this tutorial: http://www.imagineersystems.com/products/monet/Mocha_image_stabilization.mp4

I am not aware of a way to smooth the keyframes or parent keyframes within FCP, so the technique will only work in AE or a similar compositor such as Nuke, Flam, Fusion, etc.

Lastly, it is great for old dogs to learn new tricks! JP’s technique of unlinking shapes works wonderfully to track the river/ground plane in this shot. It is a bit advanced for a new user, but it solved an extremely difficult track here.
But, I did find that when tracking “only transformation” to deal with simply x,y jitter, the advanced technique was not necessary.

Best,
Ross
—End Quote—
When you say “stop tracker and move to another rock area on same plane”, do you mean for me to actually move the one existing plane I have to another area? Or should I create a new shape on that same plane?


#3

—Quote (Originally by ross_shain)—
I believe I stopped the tracker and moved the same search area to another area on the same relative plane.
Best,
R
—End Quote—
When you say “stop tracker and move to another rock area on same plane”, do you mean for me to actually move the one existing plane I have to another area? Or should I create a new shape on that same plane?


#4

Hi -

I have a client who has a challenging stabilization project. They have a lengthy aerial shot (5+ minutes). The shot was taken from a “stabilized” mount on a helicopter. The chopper was going down a canyon for the entire shot. At various times during the shot, the camera tilts down and holds this angle for a period before tilting back up.

Something was wrong with the camera mount and there is some shaking when the camera tilts down or up.

How can I use Mocha to stabilize this shot? There are NO constant pixels in the shot - it’s constantly changing.

I did try adding numerous layers, but they generate an error message when the area of interest leaves the screen. Is it possible for a layer to have an IN and OUT point?

-Ed in Seattle


#5

#6

Here’s the result of trying your recommended technique;

http://www.youtube.com/watch?v=4Lu8iEnbw5g

I’ll contact you directly about the use of the entire shot.

-Ed


#7

Hi Ross -

When you say “stop tracker and move to another rock area on same plane”, do you mean for me to actually move the one existing plane I have to another area? Or should I create a new shape on that same plane?

-Ed


#8

—Quote (Originally by J-P)—
To avoid this, after you draw your shapes, skip to the last frame then press “Align Surface”. If you have the surface switched on in the view controls you will see the four corners snap to the corners of the image.
—End Quote—

Using this method, I get this result;

-Ed


#9

—Quote (Originally by ross_shain)—
I got best results by following the following steps:

  1. tracked a a few relatively small rock areas with 1 shape.
  2. turned off all track parameters except transform
  3. Once the shape was about to go offscreen, stop tracker and move to another rock area on same plane. Continue tracking.
    —End Quote—
    Here’s what I got trying that method;

-Ed


#10

—Quote (Originally by J-P)—
Looks to me like the surface points at the beginning of the plane are going behind the camera by the time you get to the end. This is why you see the stippled blue line crossing the frame near the end of the shot.

To avoid this, after you draw your shapes, skip to the last frame then press “Align Surface”. If you have the surface switched on in the view controls you will see the four corners snap to the corners of the image.

Rather than making small selections in the water, another thing you could try is to make a large selection running either right down the river, or on the left hand bank. Draw the shape so that it covers as much of the plane as possible (including the edges where the water meets bank, as they are good for tracking). In the layer controls, select “None” for Link to Track. Now you won’t see your shape moving as you track, so you can reposition it however you like as the camera moves. Try to maximise the area of the plane that’s covered as the shot progresses. If you’re tracking the water surface, which is relatively plain, I’d recommend increasing the % pixels to track to 90.

A key concept is that the larger your shapes are, the more stable your tracking result will be.

When you’re tracking with this technique, you can turn on the surface or grid to monitor the results, as you won’t be getting any feedback from the movement of the shapes.

Hope this helps,

J-P
—End Quote—
I think that some of the shapes are covering rocks that change “planes” too much when passed over. Might be better to focus on smaller patterned areas on that remain relatively flat when passed over.

If you have the time to post me the high res footage, that would be best.

I will be working tomorrow, but otherwise can get back to you next week.


#11

Just to follow up on this thread. I played with this clip a bunch yesterday and determined that if you are trying to “smooth camera jitter” than I got best results by following the following steps:

  1. tracked a a few relatively small rock areas with 1 shape.
  2. turned off all track parameters except transform
  3. Once the shape was about to go offscreen, stop tracker and move to another rock area on same plane. Continue tracking.

To smooth stabilize, I used After Effects and the smoother to reduce the keyframes. This technique is detailed in this tutorial: http://www.imagineersystems.com/products/monet/Mocha_image_stabilization.mp4

I am not aware of a way to smooth the keyframes or parent keyframes within FCP, so the technique will only work in AE or a similar compositor such as Nuke, Flam, Fusion, etc.

Lastly, it is great for old dogs to learn new tricks! JP’s technique of unlinking shapes works wonderfully to track the river/ground plane in this shot. It is a bit advanced for a new user, but it solved an extremely difficult track here.
But, I did find that when tracking “only transformation” to deal with simply x,y jitter, the advanced technique was not necessary.

Best,
Ross


#12

If there a re “no” constant pixels (planes to track) than it will be a real challenge. Yes, layers can have in/out points but to stabilize these types of tracks, it is best to find multiple areas on the same relative plane and use the “add contour to layer” button. For example, if there are multiple buildings on the same ground plane to track, you can have additional shapes for each as the go offscreen.

Beyond this, you may have to track many different areas of the screen and do some averaging within your composite system.

If you want to post us the shot, it would help.

Best,
R

—Quote (Originally by edm81363)—
Hi -

I have a client who has a challenging stabilization project. They have a lengthy aerial shot (5+ minutes). The shot was taken from a “stabilized” mount on a helicopter. The chopper was going down a canyon for the entire shot. At various times during the shot, the camera tilts down and holds this angle for a period before tilting back up.

Something was wrong with the camera mount and there is some shaking when the camera tilts down or up.

How can I use Mocha to stabilize this shot? There are NO constant pixels in the shot - it’s constantly changing.

I did try adding numerous layers, but they generate an error message when the area of interest leaves the screen. Is it possible for a layer to have an IN and OUT point?

-Ed in Seattle
—End Quote—


#13

Ok, so I do think that you could get a decent track to stabilize on that clip.

What you would do is think about the river and patterns on the river (rocks, etc) as all on 1 plane.

Create small shapes around each element that is trackable on that plane, all on the same layer by using the “add x-spline to layer button”. (the button next to the create x-spline button).

You can track until new areas appear on the screen, stop the tracker, than add new shapes on the same layer. This is one of the features that makes mocha so powerful.

If you can post me the actual clip, we would be interested in doing a tutorial for this typoe of shot.

Contact me off forum at: rosss@imagineersystems.com

Cheers,
R


#14

I think that some of the shapes are covering rocks that change “planes” too much when passed over. Might be better to focus on smaller patterned areas on that remain relatively flat when passed over.

If you have the time to post me the high res footage, that would be best.

I will be working tomorrow, but otherwise can get back to you next week.
Best
R


#15

I believe I stopped the tracker and moved the same search area to another area on the same relative plane.
Best,
R


#16

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