Monthly Archives: September 2011

Playing with HDR… Keeping it real

In my last post I showed some of the interesting effects that can be made with HDR. I tried to make it clear that the technique can also be used to create enhanced but realistic photos. As I explained, HDR is used to add additional light information to the photo which allows these extreme effects to be created. To demonstrate a more realistic processing I'm going to use the same starting image as last time:

Single Exposure of Table

Original

Software edit of simple table exposure

Software Edit

 

As can be seen in the original image the sky is overexposed while the shadows are very dark. While this can be edited in any decent photo software, the result will look similar to the right image. This edited image shows far more detail in the shadows and some more in the sky. This edit was only made possible due to the camera saving into a RAW format.

HDR Table with more realistic tone mapping

5 Image HDR

The final edit shows the same level of improvement over the original photo (in terms of detail) as the dramatic edits of the last post. The same type of processing is applied but less strongly allowing the photo to retain a more natural feel.

Playing with HDR

HDR stands for High Dynamic Range. HDR basically refers to an image having a range of brightnesses greater than the camera is capable of capturing, in a single photo. The way these are taken is with a series of exposures which with computer trickery are combined into a 32bit picture file. These cannot be displayed on normal computer screens/TVs so are 'photoshopped' back to a regular 16 or 8bit file. While this can give realistic results, it also allows for some wacky effects to be created.

I'm not going to go into the details on how to create these effects but will provide some links to tutorials at the bottom. I wanted to test the benefit of multiple exposure HDR over single exposure pseudo-HDR (the cheat method*). Additionally, I wanted to test how many exposures are needed for the best result. The three examples below show some of the effects HDR photography can lead to:

Mini in HDRSt David's Cathedral in HDRHDR of cars

 

Single Vs Multiple Exposure HDR

There are times when either are appropriate but traditionally, the 'best' results will always come from a multiple exposure HDR. If there is movement in the scene you will get ghosting, which is the name given to the strange grey halos found around the moving objects (this can include plants/leaves moving in the wind). Software can reduce ghosting and in certain cases, remove it completely but a detailed tree scene on a windy day is going to have too much movement. *In these cases you can try single exposure HDR; this is only effective if you camera saves in RAW mode. Continue reading

Learning JavaScript 2

Following my first attempt at the name game, I released that my hint code was rubbish (but really, I knew that at the time) and that it's very difficult to guess a random name with so few clues.

First of all, the code has been improved. It will tell you how many letters you have correct from the first letter, ie first 3 letters or first 100 letters. Secondly, as additional help it can tell you every letter that is correct. This major addition should make guessing from scratch much easier. Version 2 of the name game never made it online as I was already working on version 3. Version 3 got updated to v4 since being posted!

Guess The Name Game v4

Make a guess at the name:
 
 
 
 

Continue reading

Learning JavaScript – Name Game

When I was younger I found it really interesting you could piece together 'tags' to make web pages. More recently, I've found it fascinating how the guys at Cyanogenmod and ModaCo can hack through source code for phones. They improve not only the speed but also the functionality of android phones sometimes far beyond where the original manufacturer gave up. My example is my old HTC Magic which was running Android 2.1 reasonably well thanks to Cyanogen and team but HTC left me high and dry on Android 1.6!

So the point is, I'd love to be able to do that too. I told myself while I was in Canada I would learn Java but never got round to it (busy life!). Since then I've been spending my time filling in job applications...

Lifehacker brought my attention to Codecademy, an interactive teach-yourself site currently focused on javascript, so I decided to give it a bash. Within a few minutes I was hooked and completed the whole thing in one sitting. Not terribly long but it put wood on the fire. I decided to do something with what I learnt and the result is below.

I just hope that Codecademy update with more detailed lessons in more languages in the near future. Continue reading