Tuesday, February 28, 2012

Return (and HDR images!)

I'm going to be slow getting back into blogging; that monthlong break was not just about SOPA but also because my schedule is crazy this semester.

I'm be writing again soon, but for now here's some HDR (high dynamic range) images I've taken recently. I'll write more about them soon. Most link back to their Wikimedia Commons page.

This first one is in fact the first HDR image I took: The island platform for tracks 1 and 3 at Back Bay, which serves 4 southside commuter rail lines plus Amtrak's Northeast Corridor services. Like most of these images, this went through an absurd amount of processing. I started by taking multiple exposure of the same scene with the camera held absolutely still; here, I rested it in front of me on a bench and took 1/8, 1/4, 1/2, and 1-second exposures.

Even with the camera steady, the images aren't perfectly aligned. I went into GIMP and carefully rotated and slid each image by hand to line them up perfectly, then cropped them so I had four images that were pixel-to-pixel aligned. At that point, I could actually feed them into Luminance HDR, a freeware program which offers a dozen different HDR algorithms. If, like this one, none of the results were exactly what I wanted, then I saved several of the best, then stacked them in GIMP. For this, I combined one image that gave the best blacks with two that combined for good colors.

This one, of the facade of the Westerly train station, built in 1912 by the New York, New Haven and Hartford Railroad (and now used by Amtrak), is not actually a true HDR image. I actually took a single image and made darker and lighter versions, then put those into Luminance. The result is an HDR-style image from a single starting image.

The Castle (Smithsonian Institution Building) on the Mall in Washington, D.C. This image contains ghost images of tourists who moved between exposures.

I just finished this one of Marsh Chapel here at BU last night. Despite some noisy images (Boston is quite dark at 2:00 am) it turned out well.

This is a modernist chandelier on display at the Museum of Fine Arts.