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Author Topic: TUTORIAL - Request  (Read 9543 times)

Wishgranter

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TUTORIAL - Request
« on: April 15, 2014, 01:16:59 PM »
So post your wishes here - will try cover it, or  other can do their part of helping community......
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Exhale

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Re: TUTORIAL - Request
« Reply #1 on: April 15, 2014, 09:36:41 PM »
Are you collecting topics for the TUTORIAL ?  Shall we start writing ?  ;)

Ok, I usually see  "auto masking" topic is so often...

By the way, Can't we make a filter to see most common topics.. Maybe Alexey Can? So that can be helpful for making the TUTORIAL ?

Wishgranter

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Re: TUTORIAL - Request
« Reply #2 on: April 15, 2014, 09:41:09 PM »
yup no problem... everyone if interested PLEASE put here ideas what you need to understand..........


will prepare few examples and MY way to deal with it.......


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Eildosa

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Re: TUTORIAL - Request
« Reply #3 on: April 15, 2014, 11:35:44 PM »
I hear that it was possible to align photos then change them, but I can't find how to do it.

let me elaborate :
You have a setup of, say, 30 camera.
First you shoot a sphere with pattern on it.
then you shoot someone face.

In photoscan you align the pictures using the sphere, then you replace all photos by the one of the actual face.
Since the sphere was covered by a pattern the alignment is perfect.

Is this possible?

Andrew

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Re: TUTORIAL - Request
« Reply #4 on: April 16, 2014, 12:08:01 AM »
I personally don't import camera positions, it's just too easy for fixed cameras (and their lenses) to get gradually off their previously calibrated positions. Also, if you are using multicam rig with good lighting and some of your cams fail to align, it _usually_ means your photos are not sharp enough, or your cams are spread out too far etc. In case of really pale skin/featureless subject, you can go to 'Tools/Export/Export_Cameras', save your 'sphere' camera setup and then load it ('Tools Import\Import_Cameras' when you switch to your 'face' setup.

-Andrew

David Cockey

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Re: TUTORIAL - Request
« Reply #5 on: April 16, 2014, 05:32:18 PM »
Some more on how I take photos for use in PhotoScan. Also see my post above.

Aperture setting usually is a compromise between maximizing depth of field with smaller aperture size (larger f-stop number) and decreasing sharpness due to diffraction with smaller aperture. Typically I use f 8 to f 16. Important - sensor size has a major impact on aperture effects. With the smaller sensors used on compact cameras the preferred aperture will probably be around f 4 to f 5.6.

My subjects are inanimate to I frequently use a tripod. Using a tripod allows longer exposures, and I also find  that when using a tripod the camera locations generally are more evenly spaced with the camera direction more consistent. I usually use an ISO setting of 100 or 200 though if needed to keep exposure times short I occasionally go to an ISO setting of 400. A very few times I've used an ISO setting of 800 when the alternative was not to get usable photos.

When the camera is on the tripod Shutter speed is what ever it needs to be given the aperture and ISO settings selected. When I'm hand holding the camera I use a minimum shutter speed of 1/25 second and prefer to be faster. This sometimes requires an increase in ISO or a larger aperture (smaller f-stop number).
 

Exhale

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Re: TUTORIAL - Request
« Reply #6 on: April 16, 2014, 06:34:27 PM »
Some more on how I take photos for use in PhotoScan. Also see my post above.

Aperture setting usually is a compromise between maximizing depth of field with smaller aperture size (larger f-stop number) and decreasing sharpness due to diffraction with smaller aperture. Typically I use f 8 to f 16. Important - sensor size has a major impact on aperture effects. With the smaller sensors used on compact cameras the preferred aperture will probably be around f 4 to f 5.6.

My subjects are inanimate to I frequently use a tripod. Using a tripod allows longer exposures, and I also find  that when using a tripod the camera locations generally are more evenly spaced with the camera direction more consistent. I usually use an ISO setting of 100 or 200 though if needed to keep exposure times short I occasionally go to an ISO setting of 400. A very few times I've used an ISO setting of 800 when the alternative was not to get usable photos.

When the camera is on the tripod Shutter speed is what ever it needs to be given the aperture and ISO settings selected. When I'm hand holding the camera I use a minimum shutter speed of 1/25 second and prefer to be faster. This sometimes requires an increase in ISO or a larger aperture (smaller f-stop number).

Yes, very useful..  However  those things change depending on the camera models, vendor, flashes, room light...etc   Perhaps you can mention about your setup. So it can be taken as example reference for others. What do you think ?
« Last Edit: April 17, 2014, 06:18:16 PM by Exhale »

Wishgranter

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Re: TUTORIAL - Request
« Reply #7 on: April 17, 2014, 03:21:14 PM »
OK guys, next week will start with the making of tutorials....
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David Cockey

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Re: TUTORIAL - Request
« Reply #8 on: April 18, 2014, 04:14:45 AM »
Some more on how I take photos for use in PhotoScan. Also see my post above.

Aperture setting usually is a compromise between maximizing depth of field with smaller aperture size (larger f-stop number) and decreasing sharpness due to diffraction with smaller aperture. Typically I use f 8 to f 16. Important - sensor size has a major impact on aperture effects. With the smaller sensors used on compact cameras the preferred aperture will probably be around f 4 to f 5.6.

My subjects are inanimate to I frequently use a tripod. Using a tripod allows longer exposures, and I also find  that when using a tripod the camera locations generally are more evenly spaced with the camera direction more consistent. I usually use an ISO setting of 100 or 200 though if needed to keep exposure times short I occasionally go to an ISO setting of 400. A very few times I've used an ISO setting of 800 when the alternative was not to get usable photos.

When the camera is on the tripod Shutter speed is what ever it needs to be given the aperture and ISO settings selected. When I'm hand holding the camera I use a minimum shutter speed of 1/25 second and prefer to be faster. This sometimes requires an increase in ISO or a larger aperture (smaller f-stop number).

Yes, very useful..  However  those things change depending on the camera models, vendor, flashes, room light...etc   Perhaps you can mention about your setup. So it can be taken as example reference for others. What do you think ?

Subjects are inanimate, typically boats, models of boats and stone monuments. Overall sizes range from 25m to less 0.5m. Locations include outside, inside with good lighting, and inside with poor lighting. Flash not used.

Camera is a Canon 500D/T1i. Lenses used include Canon 10-22mm, Canon 40mm, Canon 60mm Macro and Canon 18-55mm. Lens choice generally depends on amount of space available. Zoom setting is taped in place. Multiple lenses and or zoom settings may be used if needed.
« Last Edit: April 18, 2014, 06:32:18 AM by David Cockey »

Exhale

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Re: TUTORIAL - Request
« Reply #9 on: April 18, 2014, 09:11:04 PM »
Wishgranter,
Dude will you tutorial for different levels? Like for beginners and another one for Pro?
Or perhaps you consider to do it general one?
I was thinking that with lots of information, beginners may struggle ?
Will there be images for explanations ?

Cheers

Mfranquelo

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Re: TUTORIAL - Request
« Reply #10 on: April 19, 2014, 03:19:04 PM »
A good tutorial about the basics of photogrammetry and understanding some of the algorithms behind the functioning of Agisoft would be amazing as well.  ;)

James

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Re: TUTORIAL - Request
« Reply #11 on: April 21, 2014, 12:10:50 AM »
.
A good tutorial about the basics of photogrammetry and understanding some of the algorithms behind the functioning of Agisoft would be amazing as well.  ;)

I tried reading Hartley Zisserman but found this was more helpful http://m.youtube.com/watch?v=DgGV3l82NTk, and it's catchy.

bartosh44

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Re: TUTORIAL - Request
« Reply #12 on: April 21, 2014, 01:16:17 PM »
I think somethink about dslr settings and photo post production connected to final effect:
f.e. how ISO value affect to data loss, how DOF affect data loss, DOF counting with aperture settings and how it`s affecting to data loss, how sharpening inside photoshop affect better scanning, is it worth to change exposure in Camera RAW/Lightroom before importing to agisoft. Is it worth to do retopo and import to Agisoft to help scanner in some hard areas (projecting textures on empty areas)?

My most often questions are not pure from Agisoft settings becouse it`s more easy to change setting and observe than do whole process from scratch.

dcm39

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Re: TUTORIAL - Request
« Reply #13 on: April 22, 2014, 07:56:53 PM »
A good tutorial about the basics of photogrammetry and understanding some of the algorithms behind the functioning of Agisoft would be amazing as well.  ;)

I agree... some details on what algorithms PS uses would be both useful and interesting. It is very black box at the moment.

simon

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Re: TUTORIAL - Request
« Reply #14 on: April 22, 2014, 10:27:04 PM »
Any tutorials around taking your Photoscan results and optimizing them for specific uses would be great. Personally, I would love to learn a simple and efficient way to optimize my mesh and uv map for use as game assets. That might be considered off topic for Photoscan, so perhaps a tutorial on how to project a new UV map onto a mesh that you optimized externally?
Regardless, I think it is great that you are creating community tutorials. I would love to do the same once I'm able to learn enough to have something worth sharing. I look forward to seeing what you have coming.