Messages

16

General / Re: Raw file batch calibration/sync of image exposure?

« on: July 09, 2015, 11:32:31 PM »

Haha, yeah that's a always a helpful answer. I had the same experience from the "auto" button, I don't know what it did, just moved around every slider randomly. I suspect there might be more steps to getting it working correctly, I'll have to look it up I suppose.

It does actually equalize the exposure between photos fairly well, but the problem is that it also messes up the Contrast, Whites, Blacks settings  of the image.  Ideally you would just use 'Auto' to get the exposures equalized, and then set the rest of the settings back to 0. But you cannot edit (or sync) multiple image at the same time anymore with Auto exposure enabled.

To reproduce:

Open 20 RAW files in Camera RAW
Select all images
Click 'Auto' under the 'tint slider'
Observe that settings change on all images
 
Now with the images still selected, change any of the following settings (but *NOT* the Exposure slider!):
- Contrast
- Highlights
- Shadows
- Whites
- Blacks

You will see that only the settings on the first image (or sometimes first few images) are updated, the other images are not edited.

When you change the Exposure slider, the other settings are indeed updated (probably because the 'auto' mode is disabled).

We've looked into this any way possible, but there just doesn't seem to be any way around it.

Manually adjusting exposure like Bigben suggest is of course possible, but really mind-numbing work.

17

General / Re: Raw file batch calibration/sync of image exposure?

« on: July 09, 2015, 08:03:28 PM »

Yes, it's a real shame that Photoshop's Auto Exposure cannot be used on multiple images.

As soon as you enable "Auto Exposure", it messes up the contrast big time. Reverting those settings on multiple images at the same time is not possible (neither is syncing), you would have to set them back to their defaults one image at a time.

What I think is happening, is that Adobe Camera RAW enters a different mode when Auto Exposure is enabled. If you save the settings and check the XMP file, you will see that the Exposure isn't stored in the file either.

I filed a bug report with Adobe, but the knowledge of the customer support was terrible. All you get is "could you please uninstall and reinstall the program, it will fix the problem!".

18

General / Re: What is the algorithm or principle behind the function of Estimate Image Quality

« on: June 29, 2015, 12:06:10 PM »

It looks at 'border sharpness' (contrast between pixels).

Personally I don't find it very useful, because it cannot accurately detect a small directional blur resulting from camera shake.

There is some more information in this thread:

http://www.agisoft.com/forum/index.php?topic=1924.msg10245#msg10245

19

Feature Requests / Re: Blur aware texturing

« on: June 15, 2015, 11:44:42 AM »

That would be a nice feature indeed. Even a simpler version that prefers the center of a photo would be of help (since the center of the photo is often highr quality).

20

General / Re: Appropriate to post Photoscan targeted rig for sale on the forum?

« on: June 12, 2015, 08:44:00 PM »

We might be interested, depending on specs and price. Could you PM the details?

21

General / Re: build a good texture

« on: May 12, 2015, 11:25:25 PM »

I highly doubt that ISO 100 vs. 400 is the reason for the artifacts in the texture.  It's more likely simply a result of photoscan trying to blend a high number of photos together.

I agree. But without seeing some source photos at full resolution all we can do guess.

Show us source photos at full resolution and we will be able to help much better.

22

General / Re: Scanning my girlfriend

« on: May 11, 2015, 01:39:29 PM »

Yes, I think the background could help a bit to align in the laying down position, considering I am using 50mm / F2  which is not much DOF to capture a sharp background in the seated position, and also in the seated version I took the photos slightly closer.

50mm F2 will give you about 7 centimeter / 0.2 feet depth of field, that won't work for Photoscan. The more sharpness in the picture the better.

Try F11 or F13 to maximize the depth of field, you probably will need a tripod to avoid blur from camera shake (if you photograph inside).

23

General / Re: Scanning my girlfriend

« on: May 11, 2015, 11:32:58 AM »

The version where she is laying down probably has a background (carpet or fabric?) that contains more useful details Photoscan can use to align the photos.

24

General / Re: export reduced dense point cloud

« on: May 08, 2015, 01:03:59 PM »

Currently there is no way to reduce the number of points in the Dense Cloud, apart from recontructing it at a lower setting.

I started a thread in the Feature Requests section for such a feature:

http://www.agisoft.com/forum/index.php?topic=1813.msg11940#msg11940


Edit: you can also use CloudCompare to reduce the point cloud, but there is no way to import the Dense Cloud back into Photoscan, so you would have to do the meshing outside Photoscan as well.

25

General / Re: lighting underground / interior advice please

« on: May 06, 2015, 02:02:39 PM »

I think the lighting should be as consistent as possible, so either place the lights at a distance and keep them static (if they are strong enough) or set them up with the exact same angle relative to the camera.

Photoscan doesn't need shadow detail specifically, any fine detail will do. Harsh shadows are indeed bad, because often the camera doesn't have enough range to get enough detail in the shadows (or highlights start clipping).

If you photograph a wall you do not need to vary the angles, just varying the position will do. Position variations give Photoscan more information that camera rotation.

Image quality is everything, so use a tripod and a remote release cord, and check your photos afterwards and remove the blurry ones.

26

General / Re: PBR textures

« on: May 06, 2015, 01:56:01 PM »

Seen the video and its a very interesting overview.   They do not give much in depth info on how they cancell out AO and create accurate specular maps though.  Anyone have ideas?

Epic's specular maps must be generated based on diffuse / depth data, there is no way to extract specular data without using very controlled lighting conditions (ie. a light dome, totally different technique).

I think they cancel out AO/environment light by simply baking the lighting info from the lightprobe  (you can convert a mirror ball image to a spherical HDR map) to a white mesh.  If you substract this lighting info from the texture map generated by Photoscan, you should have a texture with a neutral lighting.

27

General / Re: At how many photos is it worth it to use pair preselection?

« on: May 04, 2015, 11:24:47 PM »

Marcel have experimented "years" back, and  it could NOT align my project data, on sme it was OK, but from speed/results experience i stay on no preselection.  What sort of reconstruction you do ??

We do mainly aerial style scans (so everything in a flat plane) but also scans of objects. The objects we scan have a lot of fine detail so we never have problems with alignment. I also like to align with max points at 120.000 instead of 40.000, so then the pre-selection is very useful to keep processing times reasonable.

28

General / Re: At how many photos is it worth it to use pair preselection?

« on: May 03, 2015, 02:16:13 PM »

again it depend on project, and experience...

What do you mean exactly? Can you give an example of a project where you would not use it (and for what reason)?

29

General / Re: At how many photos is it worth it to use pair preselection?

« on: May 03, 2015, 12:26:50 PM »

I always have generic pair preselection enabled. Only in the rare case that a project fails to align I turn it off. I don't see any downsides to having it enabled, and the speedup is huge.

30

General / Re: Camera calibration improving accuracy?

« on: April 29, 2015, 10:34:39 AM »

Thanks Bigben, that's interesting. I get what you mean with drifting to a mathematically correct solution, but I do wonder however how much difference there really is. There are a lot more points in the sparse cloud, and generally they are of much higher quality than photos of an LCD screen (where a recognizable detail might be 5 pixels wide + more DOF because of short distance).


I might try having the calibration target printed on a really big sheet of paper to see if that changes the results compared to the results from the LCD screen.