Entry tags:

hdr, hdtr, photography

High Dynamic Time Range (HDTR)

"...for us physicists believe the separation between past, present, and future is only an illusion, although a convincing one." - Einstein

Following up on my post about time visualization, I found out that this technique has a name: High Dynamic Time Range (HDTR).



Though the name is somewhat of a marketing ploy (riding the coattails of HDR/High Dynamic Range), the concepts are similar. Whereas HDR is a technique for compositing multiple photos to capture a wide range of light, HDTR uses multiple photos to capture a wide range of time.

An HDR image is the result of two operations: HDR + tone-mapping. The composite HDR image can't be shown directly on your monitor (which, luckily, isn't bright enough to accurately display the sun). Tone-mapping picks the best-exposed part of each image and stitches them together into something your screen can display.

Similarly, HDTR can also be broken into two parts: HDTR + time-mapping. The composite HDTR image is the entire photo stack, with values for each pixel at each time index. This can't be displayed directly on your screen because of the "convincing illusion" of linear time (you have to play it like a movie). Time-mapping picks a time index to use for each pixel in the final image.

Where the HDTR author breaks down is that he has limited himself only to 2-dimensional time gradients, and he hasn't tried to do 3-dimensional time surfaces yet. I assume that's coming though.

Now that I have all my time-lapse gear (timer, tripod, etc.), I hope to start working on TimeComposite again soon.