Thursday, October 25, 2007

Just Out

New Model: PGK-QE-KW1, "Windy".
Note: This model supercedes model PGK-QE-PPMcG1, which has been discontinued.

(Hat tip to The Unknown Googler)

Monday, October 22, 2007

A Dried Out Leaf (V)

Seam Carving

This morning's drawing exercise was another one of those "expand your comfort zone" exercises. The result was a drawing of yet another leaf (a different one this time - I'm considering the possibility of embedding the last leaf in epoxy resin, to make a cute little paperweight for sale with the ink drawing of it that's already on offer. If only I had the skills, and the time, to craft a matching set of steak knives). This morning's drawing is on Conte crayon on cartridge paper, initialled and dated by yours truly and definitely not for sale. It has a crap half and a not so crap half.

So let's file that one away in the manila folder of "Drawings - Exercise" for now and take a look at that noxious little genie I mentioned in the first post in this series - his name is "seam carving". You can check him out in this YouTube clip. What seam-carving promises is "content-aware image resizing". I find the results a bit of an eyesore.

(Note: although the link points to a video plugging commercial software for seam-carving, there are open-source packages out there as well).

Seam-carving is a way of taking "unimportant" detail - typically background detail - out of an image as it is resized, without altering the "content". That is whatever a web-page designer decided is important in the picture. It's a "solution" to the "problem" that arises when a computer user resizes a browser window and the the text adjusts to the new window dimensions, but the images just sit there, obstinately refusing to shift from their current 500x375 pixel resolution.

Here's that leaf again (the hilariously over-priced one), in a new visual context that I'll be using to illustrate what happens to an image when it's seam-carved for resizing. In this image the leaf is placed at the centre, on what appears (thanks to the perspective of the chequerboard) to be a flat, horizontal surface. Behind it, I've implied a vertical surface, or just open space.


Let's set some conditions for how the image is to be resized, if it is stretched in any direction - horizontally, vertically or a combination of both. They are:

The leaf is to remain at the visual centre of the image;
It is to stay the same size throughout the transformation.

Now let's look at what happens, under those conditions, when we reduce first the height of the image, then its width, then reduce both to smallest size we are prepared to accept.

Minimum Image Height

Minimum Image Width

seam-carve-04Minimimum Image Area

I hope it's obvious from examining and comparing these three images that the alterations to the background we've made to keep the leaf centred at the same size have altered our perception of the leaf - particularly in the last image, where the leaf appears to have grown a lot larger. To watch the process happening dynamically (in the YouTube video) is, for me, quite unsettling and a little fatiguing.

I'll leave this topic here for now and come back to it either in a new post or an update. Now that I've hit the topic of "seam-carving" we're starting to get to the meat of this series.