photography on S Anand

Automated image enhancement

Mon, 22 Nov 2010 12:10:38 +0000

There are some standard enhancements that I apply to my photos consistently: auto-levels, increase saturation, increase sharpness, etc. I’d also read that Flickr sharpens uploads (at least, the resized ones) so that they look better.

So last week, I took 100 of my photos and created 4 versions of each image:

The base image itself (example)
A sharpened version (example). I used a sharpening factor of 200%
A saturated version (example). I used a saturation factor of 125%
An auto-levelled version (example)

I created a test asking people to compare these. The differences between these are not always noticeable when placed side-by-side, so the test flashed two images at the same place.

After about 800 ratings, here are the results. (Or, see the raw data.)

Sharpening clearly helps. 86% of the sharpened images were marked as better than the base images. Only 2 images (base/sharp, base/sharp) received a consistent feedback that the sharpened images were worse. (I have my doubts about those two as well.) On the whole, it seems fairly clear that sharpening helps.

Saturation and levels were roughly equal, and somewhat unclear. 69% of the saturated images and 68% of auto-levelled images were marked as better than the base images. And almost an equal number of images (52%) showed saturation as being better than the auto-levelled version. For a majority of images (60%), there’s a divided opinion on whether saturation was better than levelling or the other way around.

On the whole, sharpening is a clear win. When in doubt, sharpen images.

For saturation and levelling, there certainly appears to be potential. 2 in 3 images are improved by either of these techniques. But it isn’t entirely obvious which (or both) to apply.

Is there someone out there with some image processing experience to shed light on this?

Comments

Jason 14 Feb 2011 11:27 am: Depending on your settings in Photoshop (i assume that’s what you’re using since you refer to it as “levels”), when you adjust levels to increase contrast (when either the left or right sliders are moved toward each other), the saturation is also increased. You can click “preserve tones” or something like that, to help keep the saturation unchanged but I don’t due to some reason I can’t recall right now. Anyway, so when you hit Auto-Levels, it moves the sliders closer toward each other (since they start out farthest away from each other). This increases the contrast and ALSO increases the saturation. You’ll also notice this effect with the dodge/burn brushes: the saturation is also effected in the applied area. Now, your test results seem similar between the ’levels’ group and the ‘saturation’ group because both groups are seeing photos with saturation increases. Note that the converse is not true: changes made only to saturation do not yield a change in contrast. The fact that hues will now stand out more from each other sorta gives the affect of “contrast” in a sense though, even if it isn’t reflected accurately in the histogram. I would still expect people to prefer the photos with Auto-Levels applied, since those photos will have greater detail and less of a hazy look in the mid-ranges, but whatever. People are hard to predict. I prefer the auto-leveled photos over the saturated photos. In fact, I almost always adjust levels, and when I do, I often decrease saturation a tiny bit depending on the subject.
S Ganesh 6 Mar 2011 3:44 am: Sharpening is always better because it is non-destructive in nature and does not add any new details unlike the the saturation and levels. In a way it is illusory but it works. It basically works on the edges and emphasize them. Internally, it can be assumed as a 2 step process, the first step is to blur the image slightly and the second step is to compare the original with blur version one pixel at a time & emphasize them. If original pixel is brighter than the blurred version, then lighten; if original is darker than the blur version, then darken. The objective is to increase the contrast between each pixel and its neighbours… Sharpening works well on images that has slight blur originally, inherently due to the way in which pictures are taken… casually on the move, non-sturdy hands etc… Hence, it appears to work on most of the pictures Advanced photo editing tools provide feature called Unsharp Masking, where it is possible to control the ‘radius’ - amount of blur and ‘Threshold’ - difference in value between original and blur when it exceeds certain value sharpening is applied…

Canary Wharf time lapse video

Fri, 07 Nov 2008 12:00:00 +0000

I left my camera near the window of my office at Canary Wharf in time lapse mode on a cloudy day. The video is playing at 60 times normal speed.

Check out the related time lapse videos. They're stunning. With this one, you can figure out which firms work till late in the night.

Comments

Sumit Dhar 27 Nov 2008 6:27 am: Hey Anand,

Did you require some additional equipment to take snaps at particular intervals?

Cheers,
D.
S Anand 27 Nov 2008 6:58 am: Nope – my Canon IXUS 70 has a time-lapse mode. I just placed the camera on
the floor and let it do it’s job for an hour :-)
Balaji 10 Feb 2009 7:53 pm: Really nice Anand… Fantastic to know that this can be done by a normal user too…

Fog in London

Fri, 22 Dec 2006 12:00:00 +0000

This is the park in front of my office in the evening. Fog completely covered London this week. Visibility: 200 ft. Hypnotic.

Panoramas on Google Maps

Thu, 21 Dec 2006 12:00:00 +0000

xRez has some stunning, large (gigapixel-sized) panoramas that you can zoom into using the Google Maps interface. It’s similar to the Gigapixel project, I think.

More views from my office

Wed, 13 Dec 2006 12:00:00 +0000

Comments

Chitra 14 Dec 2006 2:51 am: Hmmm…very busy view….
Anamika 12 Feb 2012 10:35 am: Oru yenthiratha pola ada ingey ulla vaalkai Ithu yengey poi solla, manam ishtapada villai Nam oora pola ooru illai…!

Slightly overexpose digital camera shots

Tue, 05 Dec 2006 12:00:00 +0000

Based on advice from Thomas Knoll, Michael suggests overexposing digital camera shots. This is because the on the CCD of digital cameras, the bright tones have the highest colour resolution. So you can darken images later and retain the colours well, but you can’t brighten without losing data.

Photography Howto

Mon, 04 Sep 2006 12:00:00 +0000

Digital photography how-to.

Comments

Dhar 8 Sep 2006 6:09 am: In addition to the link you have given, do check out Photonhead for tips, tricks and tutorials on Digital Photography. Incidentally, I have recently started shooting again and a few of the shots I have taken are available here.

Your camera does not matter

Mon, 02 Jan 2006 12:00:00 +0000

Your camera does not matter. “All of them can record what you are seeing. But, you have to SEE.”

Sparkler art

Tue, 12 Jul 2005 12:00:00 +0000

Sparkler art. Long exposure photos on Flickr with a sparkler. via Dhar

Kids with cameras

Tue, 08 Mar 2005 12:00:00 +0000

Kids with cameras. Give cameras to kids. Train them a bit. See what they see.

Comments

Dhar 8 Mar 2005 9:02 am: Not relevant to this post, but I see from the fiction collection you read a lot of Sci-Fi and Fantasy. But I did not find the “Song of Fire and Ice” in your list. If you are interested, I have a copy. (Oh, those Russians)
Sathish 8 Mar 2005 11:21 am: Dhar, I was also thinking of that.. I am currently reading the last part of it.. It is excellent. and thanx for your list.. I got some links to read from them

2003 Mumbai Bloggers meet photos

Tue, 06 May 2003 12:00:00 +0000

The Mumbai Bloggers’ Meet photos are online.

Comments

Mumbai Man 3 Dec 2006 10:57 pm: try this http://mumbainews.wordpress.com/2006/08/30/local-trains-time-table/

2002 in pictures

Tue, 24 Dec 2002 12:00:00 +0000

2002 in pictures – links on MetaFilter.

My kitchen

Thu, 15 Aug 2002 12:00:00 +0000

I just furnished my kitchen. While my aspiration levels were high, I ended up with this. Mind you, the photo makes the kitchen look a lot better than it really is.

Amitabh Mall

Wed, 14 Aug 2002 12:00:00 +0000

Update: There used to be an unflattering (Photoshopped) picture of Amitabh Mall here. It’s been taken down on request.

I got a digital camera. Here’s a snap from it.

Now, you may be wondering why the snap looks bad. That’s not true. Meet Amitabh, friend and colleague. Looks a little different. Unfortunately balding early. After all, he’s a consultant. Currently unsatisfied with the object of his attention (either the food or me) to the extreme. Following a unique love-life model.

Fuji Finepix 2600

Mon, 15 Jul 2002 12:00:00 +0000

I just bought a Fuji Finepix 2600. Should be getting it in a month.

PhotoSIG

Wed, 16 Jan 2002 12:00:00 +0000

PhotoSIG: a community of photographers.

A picture of me

Fri, 11 Jan 2002 12:00:00 +0000

Finally managed to put a decent photo of myself on my home page. (OK, “decent” is

a matter of opinion.)

Photographic blog

Sun, 30 Sep 2001 12:00:00 +0000

A photographic blog. Lots of similar stuff at mirror project, lightningfield. Incredible! What’ll people think up of next?

New look

Thu, 25 Jan 2001 12:00:00 +0000

I’ve replaced my old photo (left) with this new one (right). Yes, I know. I’m growing younger by the day.