úterý 31. července 2012

Panoramatic pictures and HDR

The best application for panoramic pictures I have found is ICE from Microsoft. The application is small to download, easy and fast to operate and it creates the best seamless pictures I have ever got from any panoramic software I have ever tried. And a bonus: it's free.

In the case of HDR I am indifferent. HDRtist is extremely simple to use and it aligns the pictures correctly; however, it creates a strong hallo around dark objects and the processing is incredibly slow. Furthermore, in respect to the main idea of the application, simplicity, the application should automatically crop the pictures. So the resulting HDR picture doesn't have dark and light borders caused by the aligning of the source pictures with different exposure.

Luminance HDR has a good automatic alignment tool and it creates nice realistic photos. It's my choice.

Picturenaut has a bad automatic alignment - it just shifts the pictures, but it doesn't rotate them. Hence for handheld shots it's unusable.

EasyHDR is maybe good, but in may hands it felt like rubbish.


HDRExpress has a bad alignment tool and creates strange white lines in the processed HDR photos.

úterý 17. července 2012

Chinese zodiac

I have found out that Chinese believe that people can be matched by the Chinese zodiac. Chinese zodiac differs from European zodiac that it doesn't categories people by the month but by the year. However, they have 12 signs as well and after the 12th sign the 1st sign goes. Let's look at the match table, where 1 means less compatible and 10 more compatible:


Rat Ox Tiger Rabbit Dragon Snake Horse Goat Monkey Rooster Dog Pig
Rat 9 6 4 7 10 7 3 4 10 6 8 8
Ox 6 8 4 8 7 9 5 2 4 9 7 7
Tiger 4 4 5 5 6 3 9 4 2 4 9 7
Rabbit 7 8 5 8 7 7 5 9 4 2 8 9
Dragon 10 7 6 7 9 8 8 7 10 9 2 8
Snake 7 9 3 7 8 8 4 7 4 9 8 4
Horse 3 5 9 5 8 4 8 8 5 6 9 6
Goat 4 2 4 9 7 7 8 9 5 5 4 9
Monkey 10 4 2 4 10 4 5 5 9 4 8 7
Rooster 6 9 4 2 9 9 6 5 4 4 5 5
Dog 8 7 9 8 2 8 9 4 8 5 7 7
Pig 8 7 7 9 8 4 6 9 7 5 7 8
Courtesy of http://www.findyourfate.com/chineseastro/grid.htm

I don't know about you but I don't see much. Let's do some visualization:
Conditional formatting in Excel. High levels are green, low levels are red.
That looks interesting - there are diagonal strips. Let's use Matlab to check that the strips aren't there by accident. To do that we will do random permutation test and measure uniformity. To measure the uniformity we can look at the average standard deviation in a row. And for the beginning we shift each column up by the column index multiplied by integer.

As depicted by the graph from Matlab, the maximal uniformity is reached when i=1
To visualize the result, we can use Excel again:
Excel plot when i=1
This looks meaningfully. But is it significant?

Minitab's t-test.
Minitab didn't identify the lowest value as an outlier. Hence, over finding is not significant. This is because our test is not strong enough. Nevertheless, if we generated more permutations (that are truly random), we would conclude that our finding is significant. 

And what did we find? The signs are sorted by the year. For example the difference between the rat and the dragon is four years. And they are good match. Based on our analysis of Chinese zodiac we can conclude that the hypothesized ideal age difference is in multiplies of 4 years and the worst age difference is in multiplies of 6 years. 

pondělí 16. července 2012

Chloupky

Neustále narážím na diskuze typu "rostou chloupky po oholení rychleji"? Nerostou, neb se jedná o mrtvou tkáň, která nemá, jak by mohla reagovat na oholení. Ale uvedu několik důvodů, proč se zdá, že je tomu přesně naopak.
  1. Chloupky vypadají jako kužel. A když seříznete špičku, průměrná šířka chloupku se zvětší. Tedy chloupky potom vypadají tlustší.
  2. S věkem chloupky tmavnou. A když uříznete světlý konec, chloupek průměrně ztmavne.
  3. Seříznutím jsou chloupky kratší, tedy méně ohebný. Takže působí, jako by ztvrdly.
  4. Relativní rozdíl mezi 1mm a 6mm je mnohem větší, než mezi 20mm a 25mm. Takže chloupky vypadají, jako by rostli rychleji.