Dan is releasing regular blog posts about the study at http://www.humancentric.com/GestureResearch.

There are plenty of ways to record two camera feeds. One way is to use a hardware mixer to create a Picture-in-Picture (PIP) view of the two feeds. The downsides to this approach are that quality mixers can be expensive and that they are most appropriate for fixed labs (i.e. they are often too bulky to carry off-site). Another way is to use a commercial software package such as Techsmith’s Morae. The downsides to this approach are that Morae can be relatively costly for some users (such as students) and that Morae requires some post-processing to generate videos from Morae recordings.

The basic idea for our approach is to display both videos on the screen (sized and positioned in whatever way you want) and then record the screen. For our approach, you’ll need to install Windows Media Encoder and software for viewing camera feeds, such as VLC Media Player. You’ll also need two cameras that you can connect to your PC, such as two webcams.

Here are the basic steps:

1. Open up two instances of your software for viewing camera feeds. View one camera feed in each instance. Size and position the camera feeds in whatever way is most appopriate for your needs. For example, you might have the camera feeds positioned side by side or you may have one feed scaled down and positioned in a corner, much like a traditional PIP view (as is shown in the image below). You may also want to consider turning off the window borders (as is shown for the small PIP in the image below).
2. Open Windows Media Encoder and choose the “Capture screen” option. Choose “Region of the screen”. Click the selection button and drag a rectangle around the windows that are displaying your camera feeds. Do not include the title bars on the windows or the Windows start menu/taskbar/notification area. The red rectangle in the image below illustrates the selected region of the screen. Note: Make sure that the values in the “Width x height:” boxes are even numbers; Windows Media Encoder may not work properly if either the width or the height value is an odd number.
3. When you are finished with the Windows Media Encoder setup wizard, click the “Properties” button in the toolbar and choose the “Compression” tab. Click the “Edit” button and change the video codec to “Windows Media Video 9″; this codec works better for capturing camera feeds than the “Windows Media Video 9 Screen” codec that is selected by default. Next, click on the other tab and change the frame rate to 29.97 frames per second.
4. Click the “OK” button and then the “Apply” button. You are now set up. When you click the “Start Encoding” button in the toolbar, Windows Media Recorder will record the area that you specified and save it as a .wmv video. Because of the way that you specified the region of the screen, your video will look as if it was created via a mixer or commercial software.

>> Read other Usability Lab blog entries

There are four different approaches to capturing screen video. The approaches differ in terms of cost, time required to generate a video, and quality. In the following approaches, I use the term target machine to refer to the machine that is generating the screen video that you want to capture.

Approach #1: Record the screen with a video camera

This is the most basic approach – simply point a video camera at the screen of the target machine.

• Pros:
  • This is a very simple approach that can be set up quickly.
• Cons:
  • To capture a screen in this manner, it is often necessary to set up a camera at a slight angle over a participant’s shoulder. If the camera is positioned close to the participant, such as on a tripod behind the participant, it can be particularly obtrusive. Additionally, because the camera is positioned at a slight angle to the screen, the view of the screen appears slightly distorted.
  • Many cameras create video files that require special codecs to watch. If the files are intended to be distributed or shared, it will be necessary to convert the files produced by the camera into a format that can be easily viewed by most people, such as .wmv or .mov. The conversion process can be very time consuming.
  • The quality is typically very low. A standard camera has a resolution of around 640 x 480 pixels, but monitors have resolutions that are potentially many times greater. As a result, video camera recordings of screens appear blurry. Using a HD camera will help reduce blurriness, but quality HD cameras are still somewhat expensive and HD cameras can produce very large files.

Approach #2: Recording software on the target machine

This approach involves installing recording software on the target machine that runs in the background and records the target machine’s screen.

• Pros:
  • There are a variety of free software applications, such as Camstudio, for recording screen video.
  • A number of professional products, such as Camtasia Studio and Morae, include editing features that make it easy to create professional looking videos.
• Cons:
  • Typically recording software is written to run on a major operating system, such as Windows. If you are trying to capture the display of a device that does not run a major operating system, you may not be able to use this approach.
  • The recording software can noticeably slow down a machine. In fact, it is not even possible to use the software on most UMPCs and netbooks.
  • You have to be able to access the target machine to start and stop the recordings. As a result, this software is not practical for remote setups.
  • Some of these software packages require post processing to generate videos. Depending on the output format, post processing may take a time equal to or greater than the length of the video.

Approach #3: Screen sharing

This approach involves recording a shared view of the target machine’s screen. For example, you may connect to the target machine using Windows Remote Desktop and then use recording software on your machine to record the shared view of the target machine.

• Pros:
  • This approach allows for remote setups.
  • Some tools, such UserVue have recording features built in (Note: TechSmith is phasing out UserVue).
• Cons:
  • Some tools for screen sharing, such as Webex, charge by the session or have monthly rates.
  • The quality of screen sharing video may be very low.
  • In many screen sharing setups, audio is handled via a phone connection. Unless you have special equipment for recording phone audio, the quality of the audio capture may be poor. Additionally, the video and audio will probably be out of sync because they are being delivered by two different systems that have different latencies.

Approach #4: Video signal capture

This approach involves using hardware to turn a VGA or DVI signal into a form that can be recorded by a recording application. For example, Epiphan manufacturers a variety of products that have a VGA or DVI input and a USB 2.0 output. The following is one possible setup:

1. Clone the display of the target machine. This is the basic process that you go through to set up a machine like a laptop for a projector.

2.  Connect the VGA cable from the target machine to an Epiphan device and connect the USB output from the Epiphan device to the machine that you’ll use to make the recording.

3.  Use recording software, such as Windows Media Encoder, that recognizes the Epiphan device.

The following are the pros and cons associated with this approach:

• Pros:
  • It is possible to create real time recordings that are very high quality.
  • The recording is done on a machine other than the target machine, so there is no recording software running on the target machine slowing it down.
  • You can record any device that can clone its display. This approach works well for UMPCs, netbooks, and some smartphones.
• Cons:
  • Creating high quality recordings in real time for high resolution target machines requires a good deal of processing power.
  • Hardware devices for converting VGA or DVI inputs for use with a recording machine can be expensive. Devices that support resolutions above 1024×768 and frame rates about 10 fps are particularly expensive.

>> Read other Usability Lab blog entries

Source: sidekick.com

I recently had the opportunity to use the Sidekick LX for an extended period of time. The phone has a unique swivel screen that serves as a perfect example of the difference between physical and cognitive affordances in the design of products. A physical affordance helps a person physically perform an action with a product, and a cognitive affordance helps a person think about or know how to use a product. The Sidekick has great physical affordances for opening the screen but poor cognitive affordances to indicate how to open the screen.

The swivel mechanism of the Sidekick’s screen is designed so that a light push on the top right corner of the screen will cause it to spring open with a satisfying snap. Additionally, the Sidekick is designed so that the top right corner of the screen is easily reachable by people of different hand sizes when they are holding the device. Overall, the design of the Sidekick provides good physical affordances for opening the screen.

The main cognitive affordance is that the screen is visibly separate from the body of the phone that contains the keypad, so it seems that it should be possible to open it in some way. There are no other cognitive affordances, however, to indicate to the user how to actually go about correctly opening the screen. There is a small raised piece of plastic on the lower left hand corner that is hardly noticeable. If a user puts her thumb under this piece of plastic and pushes up (away from the base of the phone), the phone will swivel open and bump into the thumb. The piece of plastic is actually a false cognitive affordance because it results in the user opening the screen incorrectly. If the user does not see the small raised piece of plastic, she is likely to assume that the phone has a sliding keypad because of her knowledge of other phones on the market.

A small cognitive affordance on the upper right corner of the screen, such as a textured surface or molded arrow, would provide a necessary clue to help users determine how to open the screen. Once they have learned how to open the screen, the swivel mechanism is easy to operate and satisfying to use.

1. I put a piece of tape on one side of the USB dongle for my wireless mouse, so that I know which way to insert it into a USB port on my laptop. The dongle is symmetrical; without the tape, I would have to guess which side of the dongle should be facing up.
2. One of my colleagues has drawn a red arrow on the lid to her laptop near the back hinge. The power port is on the back of her laptop and the arrow allows her to plug in her power supply without having to turn around the laptop.
3. Another colleague uses a blue Velcro strip to wrap her computer power supply. The strip is permanently attached to the end of the power supply that plugs into an electrical power outlet, not the side that plugs into the computer. The strip helps her easily identify which plug is hers when she wants to unplug her laptop from a power strip that has other devices plugged into it.

These “annotations” are often referred to as user artifacts. People create user artifacts to supplement the cognitive and physical affordances provided by products or to repurpose products for use in contexts or domains in which they were not intended to be used. These user artifacts are often clues to how to improve products or suggestions for new products. Additionally, users often want to “fix” a product with the least amount of effort possible. As a result, user artifacts often represent incredibly simple and inexpensive fixes or solutions.

]]> http://blog.humancentric.com/user-artifacts-people-annotate-their-stuff/feed/ 0 http://blog.humancentric.com/if-i-dont-expect-it-i-may-not-see-it/ http://blog.humancentric.com/if-i-dont-expect-it-i-may-not-see-it/#comments Tue, 09 Jun 2009 19:08:01 +0000 Jon Howarth http://blog.humancentric.com/?p=158

source:publicradio.org

After returning from a business trip in Chicago, I received a letter from my rental car company indicating that they were charging me a fee to transfer three tickets from the Illinois Tollway to my name. I thought that there had to be a mistake because I did not remember driving through toll booths without paying. In fact, I didn’t even remember driving through any toll booths at all. I called the rental car company and explained the situation. The customer service agent told me that they get a good number of calls regarding transferring tickets for toll violations. She explained that the tollways are set up so that people driving cars with an I-PASS transponder, a device that is mounted in the car and works with a prepaid toll collection system, can continue driving on the tollway without stopping at toll booths. People driving cars that do not have an I-PASS transponder must exit the tollway to pay tolls at toll booths. The reason that I didn’t remember driving through a toll booth was because I hadn’t driven through one. An Illinois Tollway camera had taken a picture of my license plate each time I failed to exit the tollway to pay the toll.

I consider myself to be a decent driver and a fairly observant individual, so how was it possible that I completely missed the signs indicating that I should exit to pay tolls? My first thought was that the signs may be similar in appearance to standard interstate signs; maybe I had just dismissed them as exit signs. An image search online, however, revealed that the signs are primarily white and yellow and that they are easily distinguishable from normal interstate signs. After some additional thought, I decided that I missed the tollway signs for two reasons:

1. I was most concerned with my primary tasks of operating the vehicle and navigating to my destination. I had relatively few attentional resources to devote to identifying and interpreting tollway signs.
2. I was simply not expecting them. Based on my previous experiences with tollways, I expected either to pay at toll booths on the tollway or to pay when entering or exiting the tollway.

My experience illustrates how our previous experiences influence how we perceive the world. I did not even consider having to exit the tollway to pay a toll. Although I may have seen the tollway signs, I certainly did not process the meaning associated with them.

I definitely understand the value of the approach used by the Illinois Tollway; it benefits the people that travel most frequently on the tollway. Understanding the value of the approach, however, does not make me any happier about having to pay the fines!