Wednesday, February 23, 2005

Picture Perception Framework

Hi CS24 folks. I thought that it would be useful to provide a framework with which to better understand the theories of picture perception we have been discussing in class. At this point important to realize that there is not one synthesized view. Instead, there are 4 main schools of thought when it comes to thinking about how we perceive 2D visual stimuli.

1. The Symbolic View, which was spearheaded by Goodman. This view purports that pictures are arbitrary symbols of depicted scene--a code that must be decoded by the viewer. The idea is that arbitrary pictorial conventions must be learned, just like learning a language or learning how to read. While this is good for explaining images filled with metaphors, it looses ground with experiments that show the universal interpretations of pictures (like the anthropological studies of African tribes that have never seen pictures before, but can easily understand pictorial representation with familiar objects).

2. The Constructivist View, which is a very popular view lead by academic figures such as Gombrich, and the writer of Visual Intelligence, Donald Hoffman. This view suggests that a picture is an ambiguous index of a depicted scene and that pictorial cues or clues that are correlated but not reliable (for example, breaking into a sweat is an index of fever, but it does not necessarily mean that we have a fever). We as viewers must infer or construct an interpretation of the scene, based upon prior knowledge. The idea is that we go “beyond the information given” which is consistent with the “Inference Perspective” (proposed by Rock) and current Bayesian models of vision.

3. The Ecological View, is the viewpoint proposed by Gibson. This view suggests that pictures are icons of depicted scene--that is, 2D picture are not “similar” to 3D scene, but Light from the picture “shares characteristics” with light from real scene. Essentially, we are able to recognize the contents of pictures because they capture aspects of information about true 3D scene, which are not arbitrary or ambiguous (e.g. linear perspective was not chosen arbitrarily but actually captures the effects of viewing depth in real 3D space). This viewpoint is consistent with the “Stimulus Perspective” where the viewer detects information within pictures, without prior knowledge or inference, it is based on how we evolved as humans.

4. The Gestalt View, best represented by the work of Arnheim. This view suggests that picture elements are organized into 2D or 3D figures according to innate principles such as simplicity, good form, Pragnänz, Figure/ground, grouping, continuation (the ideas we discussed in class). The problem of this view is that there is no definition of “simpler” and many of the boundaries between the innate principles are hard to parse apart. I should mention though that the research of Gestalt theorists have huge implications for composition in abstract art, and many artists, such as Klee were inspired by the ideas of Gestalt Theorists.

Hope this explanation is useful. If you have questions I will do my best to answer.

Thursday, February 17, 2005

like your ads, only someone got paid

Wednesday, February 16, 2005

Car Ads up for Viewing

You can now see the ads at

If you turned in images late they may not be up yet--but will be soon.

Please look through the work before class Thursday.

Wednesday, February 09, 2005

On The Topic of Car Ads and the Analysis of Images: Food For Thought

I found this Volkswagen ad very interesting in respect to what we have been discussing in class.

No, I am not a violence loving creep. This link explains why I find this ad so interesting.

What can be done with the Car Ad images?

these are responses to various email questiosn i have received:

The "paths" are included in the files for convenience only--you do not need to use them.

You can use any part of any image (just select what you want with regular selection tools and ignore the path). You can take the head of one person and stick it on another, remove/rearrange landscaping, use animal parts, combine people and animals, whatever inspires you.

You can alter the car's images in the ads, (ie. stretch them, add
shrink them, add different paint jobs, add extra wheels, etc...)

You can mkae the cars attract groups that are not people. (ie.
animals, inanimate objects, etc...)

You can make the cars travel on something other than roads, (ie.
fly, swim, etc...)

Tuesday, February 08, 2005

Car Ad Assignment Tips

For those of you with questions about Photoshop and the assignment, my TA hours will be starting tomorrow (Wednesday) Feb. 9 from 7-8pm in CIT 227 (2nd floor by the Swig Board Room--if you are standing between and facing the elevators, walk past the fishbowl, take a left, and then another left).

Tips to get started:
If you don't already have it, you can download Adobe Photoshop at If you are on-campus, you will also need to download KeyAccess. If you are off-campus, you will need to download Virtual Private Network (VPN) Client as well as KeyAccess.

To get started, create a new Photoshop file with a width of 1024 pixels, height of 860 pixels, and resolution of 72. All the environment images, except for the last one, are already set at this size if you prefer.

Choose which images you would like to work with here by right clicking on the filename and downloading the file to your computer.

In Photoshop, you should be able to view the path(s) for each image in the "path" tool palette window on your right (if you don't see it, go to "Window" and make sure "Paths" is checked). To select the image inside a path, either 1) right-click (alt-click for Mac) on the path in the path palette and select "Make Selection" or 2) click the button at the bottom of the path palette window that says "Load path as selection" (the button shows a dotted circle). Then you should be able to copy and paste the selection into a new file. Note: if the copying doesn't seem to be working, make sure that you are on the correct layer in the "layers" tool palette window.

Feel free to email me at if you have any questions or problems. Have fun!

Monday, February 07, 2005

Bamyian Buddhas

I thought the discussion was terrific in class--especially since everyone I had spoke with before thought that it was a non-issue because "of course we should rebuild them." (!) If anyone would like to add any more thoughts, please do so here. Some of the key issues are:

* Whom would reconstruction benefit?

* What, if any, priority should 'art" and historical documentation have over immediate human needs?

*Would reconstruction elsewhere retain any of the same meaning? And what abotut scale issues--too big for a museum?

*How does the choice to rebuild compare with the US discussion about twin towers site? With decisions to rebuild cathedrals after bombings in WW II?

* What is the best reaction to the Taliban's actions (in terms of visual treatment of the site)? What messages can we send?

CIS PASS Class TODAY 4:00pm-6:00.CIT Room 269.

Thursday, February 03, 2005

Bamiyan reconstruction site back up

Wednesday, February 02, 2005

The reality of photos and image manipulation

Most of you have probably heard of online photoshop contests, where the idea is to modify an image in a creative way, ideally without the manipulation being obvious.

Well, an entry to one of these somehow got out and became a big, public hoax. (Despite a fairly obvious cue to the unreality of it in the caption, which includes the statement "Also the scientists readily admit that the computer will require not yet invented technology to actually work".)

Here's a story concerning one of the several people-who-should-have-known-better to fall prey to the hoax. And another (scroll down some for the relevant part of the article). There were also a lot of reports of people's teachers, bosses, etc. getting hold of the image and thinking it was real on the forums of the site it came from.

And here are the comments of the creator of the image.

And then there is the new image hoax story; apparently some terrorists took a picture of an action figure, and claimed they had a captive soldier and were going to behead him. Here's the AP story, and here's a story about it being a doll.

Just thought it might be relevant!
- Emily Bond

Bamiyan reconstruction site down

Their server crashed and they aren't sure when it will be back up. I'll bring in a printout of the article and can summarize quickly in class.

Reminder: PASS course Mon feb 7, 4-6pm, CIT Room 269

This course will cover Photoshop and Illustrator basics, as well as some more advanced things you will need for the assignmments.

Hoffman--books in next week

more as it occurs...

links fixed (Bamiyan)


Thanks for pointing out the link issues. They are all fixed except for the link to the Swiss research Institute. I exchanged emails with personnel there during the fall and have emailed them now to find out what the problem is. I'll keep everyone posted.

Fixed Links for Buddhas at Bamiyan

Anyone else having difficulty with the links? Since the web reading's link leads to the exercise/discussion page, I assumed our reading is the "background materials" there. Rosemary, most problems were simply spaces at the ends of links listed below, creating the character % when you follow the address.

CS24 peers--here are some working links:

• BBC (

• "Benjamin Britton's Lascaux Project" (

• "Ghiberti's doors" (

• Photogrammetry is missing an "l" at the end of html, but the bigger issue is apparently the main site ( is no longer there.

Katherine Lau

Tuesday, February 01, 2005

Hoffman book (Visual Intelligence) not in at Bookstore

Andy and I were notified today that the publisher of Visual Intelligence failed to ship our copies (it's still being printed). The bookstore is trying to find enough copies through other vendors and through online sources of used books. We will keep you posted.

MOTD from Tuesday, Feb 1, 2005

Visual Memory exercise: If you didn't do itafter class, do it before Thursday. It is linked off the syllabus.

Try logging into the machines in the MS Lab (167). No one had trouble today, but check so that you are able to start working on projects next week.

due Thursday: readings in Visual Methodologies and on the Bamiyan Buddhas

SHREK 2 screening: this Friday at 8pm. Meet in the CIT Lobby at 7:50--elevators are locked after 5pm. Pizza!