Are there any open source programs that can use RAW for stitching photos?

Question

I want to stitch lots of photos together since getting my Sigma 10-20mm. I've got a couple of projects in my head I want to do as well. However, my experience using Hugin for stitching hasn't been wonderful (I'm probably just bad at using it) and RAW is far nicer to edit in. It's been particularly annoying to move out of lightroom, convert everything into TIFF and hope that it looks ok.

Additionally are there any better recommendations people could give me on stitching software in general (doesn't have to be open source)? I'm aware that photoshop 3 has a stitcher but I'm still used to using lightroom.

Thanks!

Asked by Comrade Stokesi

Answer

There's unlikely going to be anything that takes several RAW photos, stitches them together, and then produces a RAW pano, which is what it sounds like you're after. The Photoshop + LR (and other pano software that take RAW as an input) combo makes it seem like it may because it loads up your RAWs to use, but its still TIFF converting and you still end up with TIFF.

RAW isn't really a file format like you're thinking. Its a collection of raw sensor data in a container. By nature, running it through the pano process will make it not RAW.

Use Lightroom to exposure balance your pano individual shots first, and then try Hugin with the TIFFs. Personally, I've had reasonable success trying that lately.

Answered by rfusca

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Open standards in digital photography

Question

I'm interested which digital camera models and brands are most open standard friendly. I'm more an open source fan than a photographer, so I can be picky about openness and tolerant with performance and image quality. I suppose there won't be analogy of OLPC computer in digital camera world, but there shall be some models that meet more open standards than others.

Here is a list of standards I know about (I'm not 100% sure about this, feel free to correct me):

• ¼" tripod mount is free to implement
• 4/3 lens mount is more open than others, like Canon or Nikon mounts. It's not fully open, but at least interested third party lens manufacturers don't have to reverse-engineer camera electronics.
• SDHC is more or less open
• AA batteries are a standard factor compared to proprietary Li-ion batteries
• Adobe DNG open raw format is supported by some cameras from Pentax and other manufacturers

So, any other recommendations?

Asked by user713303

Answer

There are literally thousands of "standards" used in digital photography, but few address what you seem to be asking: open standard hardware, os/file systems, etc. ASA/ISO film speed is a standard, as are APS-C and 35mm sensor sizes.

Sadly, all of the consumer oriented brands (Nikon, Canon, Sony, Olympus, etc.) are totally locked into a philosophy of locking you into their "system" with their hardware, software in the camera, software to decode the RAW files, etc.

And, IMHO, much of their proprietary software is second rate.

I have no hope for the DSLR business, perhaps cell phone cameras can take over P+S

Answered by Pat Farrell

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Is the format for the distortion and chromatic aberration correction of µ4/3 lenses documented?

Question

Olympus micro 4/3 cameras apply distortion correction on their in-camera JPEGs when used with a micro 4/3 lens. Panasonic cameras correct both distortion and chromatic aberration with their lenses.

Although I'm not sure where this information is stored, since this also works on the off-camera software I'd guess that it's in metadata attached to the RAW images.

Is this format documented anywhere (either officially or through reverse-engineering)? It would be nice to be able to implement this correction in open-source software (specifically lensfun) without needing to either calibrate the lens or rely on the calibration database.

EDIT: to make this perfectly clear - the objective is to take the RAW file from the camera and be able to apply the same correction that the in-camera JPEG gets, or that gets applied by the Olympus software.

Asked by RAOF

Answer

There appears to be a pretty rich Open Source movement in the Linux community to generate raw file format processors for linux. I've found several wiki's that are working on compiling file format details for known RAW formats, and there are a few applications that contain some code. Some formats, like Canon's .CRW and .CR2, are open specifications and you can find the details online. It seems that the .ORF format (or the Panasonic .RAW format) are not open, so the only thing knowledge that can be gleaned is via reverse engineering. I doubt that the information you are looking for is contained within EXIF data, however if it is stored, it should be available in RAW format metadata. Here are some resources:

• http://osp.wikidot.com/raw
  • Project to decode RAW file formats
• http://osp.wikidot.com/raw-linux-software-comparison
  • List of open source programs that decode .ORF (and other formats)
• http://www.cybercom.net/~dcoffin/dcraw/
  • Contains the DCRaw project
  • Has some free code that does basic interpolation of raw bayer info for .ORF
• http://www.cgsecurity.org/wiki/PhotoRec
  • Home of PhotoRec
  • Source code can be downloaded here:
    • http://www.cgsecurity.org/wiki/TestDisk_Download
• http://www.rawsamples.ch/index_en.php
  • Contains a bunch of sample raw formats, including Olympus

The bulk of a RAW file format is a direct sensor data dump, either from a Bayer array, CCD, or possibly a layered CMOS (like the Foveon.) That makes the image data pretty easy to spot, as it is very patterned. The data you are interested in will likely be more complex and and random, either stored at the beginning or possibly the end of a file format. I've done a fair amount of file format reverse engineering in my day, and may be able to recognize some structure in the .ORF format for you. (I worked on an editor for Sim City 4 and the Sims 2 a number of years ago, and alongside a few others, we must have decoded some 300+ file formats via HEX. I may be able to help provide some insight if I can get a hold of some .ORF raw files from the camera+lenses you have access to.) Your best bet, if you wish to have support for lens correction added to lensfun, would be the open source movements to bring RAW processing to Linux.

UPDATE:

Alternatively, it seems like Adobe has released a Lens Profile generator that can generate lens profiles for Lightroom 3/ACR. They cover geometric distortion, chromatic aberration, and vignetting. I know you mentioned something that could be used with the program lensfun, but this might be a viable alternative.

Answered by jrista

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Are there any good open source noise removal tools?

Question

In particular that run natively on Linux.

Asked by txwikinger

Answer

There are several different plugins for gimp to remove noise.

Answered by chills42

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Is there an equivalent to Adobe's “Vibrance” in Gimp?

Question

See: What's the difference between Saturation and Vibrance in lightroom?. In a nutshell, it's a "smart" color adjustment that increases saturation selectively, leaving skin tones and other saturated colors alone.*

I'm curious if there's any equivalent in Gimp.

I've found a couple of plugins and scripts that use the same word "vibrance", but in everything I see, they don't mean the same thing. Usually, it's "super-saturation", as in this script, which claims it's an "implementation of a 'digital velvia'. I'm not looking for that. The Adobe feature seems to be a more subtle (and therefore more useful) tool for photo editing.

If nothing exists, is there a convenient (or even less-convenient) way to emulate it?

---

Thanks for the great answers so far. I've added a bounty to the question specifically for an answer to whether the Adobe feature does anything special with skin tones, and how to recreate that generically.

Answer

If Matt's answer about the nature of vibrance is correct (and the Adobe documentation agrees), you may be able to obtain a similar effect in GIMP. However, I don't have any Adobe software, so I can't judge how closely this actually matches Adobe's effect.

Use Colors -> Components -> Decompose, decompose to Hue/Saturation/Value or Hue/Saturation/Luminance. Select the Saturation layer and use Curves to boost the saturation of the unsaturated parts of the image. (That is, the middle grays of the saturation layer. You may want to avoid boosting the saturation of the very darkest, least saturated parts of the saturation layer, because unexpected color casts can happen in areas that are very close to a colorless black, white, or gray.) Use Colors -> Components -> Recompose to apply the change to the original image.

That's pretty clumsy compared to using a slider, and it doesn't offer any smarts about skin tones, either. It may be possible for someone familiar with writing GIMP scripts (i.e., not me) to streamline and improve it, though.

Here's a photo I tried this method with. I tried to get about the same increase in saturation in the grass with both the ordinary saturation control and by using curves on a decomposed saturation layer. You can see that in both adjusted pictures, the grass is much more saturated, but that the simple saturation control also puts the reds in the fence and in the dogs' fur way over the top, where the curves method didn't.

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How to create two layers in “Gimp” and merge them back into one?

Question

How do you create two layers in "Gimp" and merge them?

For example, I would like to load an image, create two identical layers, edit each layer in different ways, then merge them into one final version.

Specific instructions for gimp are preferred.

Answer

This is easy. First, if you don't have the Layers window open go to the Windows menu and choose it. You don't actually need that, but it's handy. It's a small "utility" window which typically floats near the right side of your screen. And open your file, if you haven't yet. With that window open, you can click on the existing layer in the image (probably Background), and then click on the Duplicate Layer button below — or press Shift-Ctrl-D. Then, to merge that layer back down again, go to the Image menu and pick Merge Visible Layers (Ctrl-M). You can also use Flatten Image. Alternately, if you have more than two layers, there's Merge Down in the Layers menu, which does what it says.

Gimp has completely customizable keyboard shortcuts, by the way. Look at the bottom of the Edit menu for Keyboard Shortcuts (may be mixed in with the Preferences in some older versions of Gimp). That way, if something doesn't have a shortcut, or you don't like the default, you can fix it.

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How does the Curves tool work in GIMP?

Question

I started using GIMP recently, and came across an option called Curves under the Colors menu. What does this tool do, and how do I use it correctly?

I get some good colors if I make a graph in 'S' shape. But what exactly is the meaning of it? How do I use this tool to enhance my photographs?

Answer

The GIMP's curves tool is virtually identical to PhotoShop's Curves tool. Almost all photo manipulation tools have a way of doing that action. There are a number of good explanations of it out on the internet if you look for photoshop: http://www.google.com/search?hl=en&q=curves+adjustment+in+photoshop

this one however is fairly thorough in it's explanation of what it's doing: http://www.cambridgeincolour.com/tutorials/photoshop-curves.htm

(disclaimer, it's been a good 3 years since I've used the GIMP, it's possible they've changed it since then, but I highly doubt it since the curves tool is one of the more fundamental advanced editing tools.)

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How to understand curves option of colors in GIMP?

Question

I started using GIMP recently, and came across an option called Curves under the Colors menu. What is the significance of it and how to use it correctly.

I get some good colors if I make a graph in 'S' shape. But what exactly is the meaning of it? How do I use this tool to enhance my photographs?

Answer

The GIMP's curves tool is virtually identical to PhotoShop's Curves tool. Almost all photo manipulation tools have a way of doing that action. There are a number of good explanations of it out on the internet if you look for photoshop: http://www.google.com/search?hl=en&q=curves+adjustment+in+photoshop

this one however is fairly thorough in it's explanation of what it's doing: http://www.cambridgeincolour.com/tutorials/photoshop-curves.htm

(disclaimer, it's been a good 3 years since I've used the GIMP, it's possible they've changed it since then, but I highly doubt it since the curves tool is one of the more fundamental advanced editing tools.)

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Understanding curves option of colors in GIMP?

Question

I started using GIMP recently, and came across an option called Curves under the Colors menu. What is the significance of it and how to use it correctly.

I get some good colors if I make a graph in 'S' shape. But what exactly is the meaning of it? How do I use this tool to enhance my photographs?

Answer

The GIMP's curves tool is virtually identical to PhotoShop's Curves tool. Almost all photo manipulation tools have a way of doing that action. There are a number of good explanations of it out on the internet if you look for photoshop: http://www.google.com/search?hl=en&q=curves+adjustment+in+photoshop

this one however is fairly thorough in it's explanation of what it's doing: http://www.cambridgeincolour.com/tutorials/photoshop-curves.htm

(disclaimer, it's been a good 3 years since I've used the GIMP, it's possible they've changed it since then, but I highly doubt it since the curves tool is one of the more fundamental advanced editing tools.)

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How safe is CHDK?

Question

I've played with time-lapse photography using my father in law's Canon Rebel, using a USB cable, gphoto2 and an Ubuntu laptop. I want to create similar videos using my own A590 IS, but it cannot be controlled from a USB cable. The only solution I found on the web is firmware enhancement using CHDK.

How safe is CHDK? Is there really a way back? Are versions above 1.xx mature?

Adam

UPDATE: Thanks for all the advice. I've successfully installed CHDK on my SD card and shot my first time-lapse using my A590. Works great!

Answer

As you can see right on the main CHDK wiki - "Temporary – No permanent changes are made to the camera." You also can find very detailed information in the FAQ here.

Basically - Yes you are hacking your camera. So things can happen that the original manufacturer did not intend(if this wasn't true, you wouldn't want it anyways). But the chances of any permanent damage to your camera are near 0.

Technically CHDK is not firmware. It does not permanently reside on the camera. You can remove it, and go back to your factory default settings and firmware without any issues. Overall - install away!

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Please suggest a workflow on Mac using only free/open source software

Question

I own a D90 with a Nikon 50mm f/1.8 prime lens. However ever since buying my camera I am struggling to find a proper workflow to process RAW images on my Mac which does at least the following

1. Adjust shadows and highlights.
2. Adjust an image via its histogram.
3. Adjust white balance.
4. Adjust exposure.
5. Crop a photo.
6. Present a preview of how the photo may look like after printing.
7. Apply EXIF tags.
8. Apply watermarks.

So my question is what kind of workflow should I follow, if I were constrained to use only free software on my Mac?

Edit: Please also suggest a software or a set of software applications to use.

Edit: Flagged as a wiki question since there can't be correct or perfect answer.

Edit: Given the fact that a freeware will probably not be able to cut it, I have come to the conclusion that I will need to buy a low cost software for this. I am keen on using Lightroom but may have to settle with iPhoto.

Answer

Given that the reason for the question is price, I encourage you to rethink this constraint. How much is your time worth? You can get excellent post-processing software for little money compared to a lens. For example, Bibble can do everything above in the same application (might need a plugin for the watermark) and it costs only $100 for the lite version.

I tried to go the same route (on Linux) and got tired of screwing around with freeware. The commercial software is way better and your time is worth more than you think it is - particularly since the smoother post-processing is, the more fun photography will be. :)

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What are the key photography-related features from Photoshop that are missing in GIMP?

Question

I am on a tight budget and chose to use GIMP for editing since it is free.

What important photographic post-processing features am I missing from Photoshop?

Answer

For photos? Not too much, actually. GIMP lacks automatic HDR processing. It doesn't have adjustment layers - although you don't need those too much for photos. Photoshop's Hue\Saturation dialog is superior. Photoshop CS5 has content-aware fill, which GIMP lacks, but there's a GIMP plugin called Resynth that does about the same thing:http://www.logarithmic.net/pfh/resynthesizer

Some pretty good art has been done in GIMP. (My snow photomanip, for instance) It's more about the artist's skill than the tools he\she uses.

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What open source software for auto-alignment of photographs?

Question

Do you know any open source tool to automatically align images, similar to the auto align feature in Photoshop?

Answer

Alignment of multiple images taken from the same point

If you are not making a panorama, but just aligning an image stack for focus stacking, exposure fusion or HDR, then align_image_stack from Hugin project is one of the simple yet very useful tools.

For example, if your have 3 files a.jpg, b.jpg, c.jpg, to align them you may run:

align_image_stack -a aligned_ a.jpg b.jpg c.jpg

which will produce three TIFF images, aligned_0000.tif, aligned_0001.tif and aligned_0002.tif, which will be well aligned. Now the images are ready to be, for instance, enfused:

enfuse aligned_*.tif

If you prefer the graphical interface, or you want to align only partially overlapping images (like in panoramas), then use Hugin itself, it is a very powerful and flexible software.

Alignment of stereo pairs

From your comments I see, that you want to create stereoscopic images. The keyword to search for is anaglyph, not align.

For this purpose I used Stereo Photo Maker, which is not open source, just a free Windows program. It runs well under wine too. But I almost never used its automatic alignment feature, because I prefer to align images manually, watching the composite 3D image. By aligning the images manually I can also choose what exactly is “in focus” (one cannot align everything in a stereo image).

SPM can also optimize color anaglyphs to reduce ghosting, a very useful feature.

There are some scripts and tutorials for Gimp (e.g. anaglypher, script-fu-make-anaglyph, this short tutorial). It is relatively easy to build a monochrome anaglyph through layer effects and by moving a layer manually, it is not always working well for color anaglyphs.

Finally, there is -stereo option of composite command of ImageMagick, but I didn't use it.

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