Image overlay (NOT edge overlay)

reyalp

12690

Re: Image overlay (NOT edge overlay)

« Reply #10 on: 25 / September / 2011, 16:50:27 »

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Quote from: msl on 25 / September / 2011, 16:43:52

Quote from: waterwingz on 25 / September / 2011, 12:24:18
What he wants is a way to put a semi-transparent version of an original jpg image from the SD card onto the camera LCD while in shooting mode so that you can exactly line up a new photo - maybe months after the original photo was taken.

Ok, the RAW development was the wrong approach. But an overlay picture with variable opacity should not be generated from a JPG . This needs many computing power for decoding. Saving the LCD image buffer is a good way.

msl

You would have to update every time the live view updated, which could be quite expensive.

Hmm, actually, updating every other frame would give you an ugly transparency effect, I suppose...

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waterwingz

12044

Re: Image overlay (NOT edge overlay)

« Reply #11 on: 25 / September / 2011, 16:55:30 »

Quote from: reyalp on 25 / September / 2011, 16:50:27

You would have to update every time the live view updated, which could be quite expensive.

Maybe worth the expense for the few special times you would want to do something like this ? There are a few long duration time lapse images I would like to try - this would make it possible.

Don't edge overlay & zebra need to do the same sort of updates ? Granted - they are simpler images.

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reyalp

12690

Re: Image overlay (NOT edge overlay)

« Reply #12 on: 25 / September / 2011, 17:17:53 »

Quote from: waterwingz on 25 / September / 2011, 16:55:30

Quote from: reyalp on 25 / September / 2011, 16:50:27
You would have to update every time the live view updated, which could be quite expensive.
Maybe worth the expense for the few special times you would want to do something like this ?

If it works, sure.

Quote

Don't edge overlay & zebra need to do the same sort of updates ? Granted - they are simpler images.

No, they operate on the bitmap buffer, which doesn't update at the same framerate as the live view. It's also smaller. This would have to be done in the live view.

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Televerket

Re: Image overlay (NOT edge overlay)

« Reply #13 on: 21 / October / 2011, 12:28:45 »

Does this thread deal with the same issue?:
http://chdk.setepontos.com/index.php?topic=2070.msg19085#msg19085

There is a mention there, that it is able to achieve, using stereodata maker. Do they even aim at the same function as we do in this thread? My English is perhaps not the best, especially when it comes to technical terms.

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Lebeau

Re: Image overlay (NOT edge overlay)

« Reply #14 on: 21 / October / 2011, 15:03:59 »

Why overlay an image when you could do this overlay in post-process using Autopano
http://www.kolor.com/panorama-software-autopano-pro-interface.html

Take 2 or more pictures and Autopano will align them and generate aligned but distinctive files.

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Televerket

Re: Image overlay (NOT edge overlay)

« Reply #15 on: 21 / October / 2011, 15:40:39 »

Quote from: Lebeau on 21 / October / 2011, 15:03:59

Why overlay an image when you could do this overlay in post-process using Autopano
http://www.kolor.com/panorama-software-autopano-pro-interface.html

Take 2 or more pictures and Autopano will align them and generate aligned but distinctive files.

Have a look at these photos: http://zeitsprung.animaux.de/

In order to be able to shoot a picture from exact the same position as an existing image, you can not give it a rough estimate and align the images later in your computer, that would be too much imprecise.

What we are looking for is a feature of CHDK in which the camera would display an existing image of some, with 50% opacity. This would enable the image that one is shooting to be very much aligned with the existing image.

Obviously, improvements could later be done using the computer. However, one can not compensate to much if the image is shot to different from the original image.

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ltraynor

Re: Image overlay (NOT edge overlay)

« Reply #16 on: 28 / March / 2012, 07:08:33 »

What format are the edge files that you can save in Edge Overlay mode? Wouldn't a possible solution be to use some external program to generate edge type files from JPGs and then load them in the Edge Overlay mode? If all you are looking for is synchronising the shooting spot between two photos, then that should be enough.

A software alternative to synchronising two shots that were taken from almost the same site would be a perspective transformation in programs such as Photoshop or ImageMagick. In this transformation any number of points (e.g. A, B, C, D) map onto an equal number of points on a target image (A', B', C', D'). If four points are used the transformation is exact, five or more points involves some averaging. Of course, this raises some issues of perspective distortion when the two shooting spots differ by a large amount, but for small differences the results should be acceptable. See www.skeptic.de/PHP_Tutorials/square.htm for an implementation in Imagick (PHP).

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feklee

Re: Image overlay (NOT edge overlay)

« Reply #17 on: 07 / June / 2012, 15:00:23 »

I am interesting in the same feature: live image plus overlay (or vice versa)

I've read here and in related threads:

Edge Overlay‎: Would that work if, say, I take a picture of my computer screen (as overlay), and then go on to take a new picture? (almost unusably cumbersome, of course)
Custom grids: Hm, looks like the solution for the OP. He could just draw a custom grid based for each house he wants to photograph. Wouldn't that work?

Finally, as I don't have a Canon camera (yet), I could get one with support for Magic Lantern. This firmware offers two quite interesting features: Ghost image and custom Cropmarks. In fact it doesn't have to be a Canon camera at all...

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