| In this Section: |
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General WinVis Questions.
WinVis for Matlab.
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| General WinVis Questions |
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What are the general browser requirements for using this website?.
What are the minimum system requirements to use the WinVis system?.
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What are the general browser requirements for using this website? |
The minimum browser requirements for using the WinVis website are as follows:
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Internet Explorer 4.x or higher or Netscape 4.5 or higher
Cookies must be accepted. In Internet Explorer, this means that the privacy setting must be 'high' or lower.
JavaScript must be enabled.
Popup Blocking software should either be disabled, or configured to allow the Neurometrics website to show popups. Various features of our site use javascript popup windows to display content. We do NOT and will not allow third party popup windows on our site.
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Our website is best viewed with the following browser settings:
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Internet Explorer 5.0 or higher
Privacy setting of 'High' or lower
Always check for new content before loading a file from the browser cache.
JavaScript enabled.
Popup Blocking software should either be disabled, or configured to allow the Neurometrics website to show popups. Various features of our site use javascript popup windows to display content. We do NOT and will allow third party popup windows on our site.
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If you have any questions, please contact us. |
What are the minimum system requirements to use the WinVis system? |
Suggested minimum hardware:
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Windows 98, 2000, XP
128 MB of system RAM or more
a PCI graphics card |
This system should be able to generate most static images and very simple/short temporal sequences in a reasonable amount of time. Generating more complicated stimuli and temporal sequences will require an extended period of time and likely over run the available memory.
Recommended hardware:
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Windows 98, 2000, XP
1.0 GHz or faster processor
512 MB of system RAM, the more the better
an AGPx4 graphics card |
This system will provide adequate functionality and performance, allowing for complex trials with many images at high resolutions. This system should be able to generate most images and temporal sequences in a reasonable amount of time. However, the process of generating temporal stimulus sequences requires a great deal of processing power. In general increasing the system's RAM, processor speed, or upgrading to a better video card will help improve performance. |
| WinVis for Matlab |
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What is WinVis For Matlab (W4M)?.
What are the hardware requirements for W4M?.
What are the software requirements for W4M?.
Why am I seeing smiley faces on all my stimuli?.
When I try to install WinVis For Matlab, the installer fails with the error: Either Matlab is running or you do not have permission to copy files into the destination folder. What could be wrong?.
I have successfully Installed WinVis For Matlab, what do I do now?.
I downloaded WinVis for Matlab (or WinVis for Matlab w/ Digital/Analog IO). Do I need to download the W4M User's Manual?.
Why do images in W4M look brighter than the same image when viewed through Matlab's IMAGE command?.
Why does Matlab returns an error saying "Undefined function or variable 'WinVis'" when I try to initialize the WinVis system?.
How can I integrate my stimuli from the online tools with W4M?.
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What is WinVis For Matlab (W4M)? |
| WinVis for MatlabŪ is a psychophysical testing platform developed by the Neurometrics Institute. This powerful tool allows users to combine stimuli into elaborate trials and experiments. With WinVis for Matlab, users have specific control over display settings such as resolution and bit depth, and are able to access the full graphical power of their PC. WinVis for Matlab is designed with the needs of a psychophysical scientist in mind, so it is both flexible and powerful enough to be useful in most settings. |
What are the hardware requirements for W4M? |
Suggested minimum hardware:
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200 MHz processor or better
64 MB of system RAM or more
a PCI graphics card with 8 MB or more of onboard RAM
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This system should run WinVis for MatlabŪ with minimum functionality, allowing for simple trials with few images.
Recommended hardware:
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1 GHz or faster processor
512 MB of system RAM, the more the better
an AGPx4 graphics card/bus with 16 MB or more of onboard RAM
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This system will provide ideal functionality and performance with WinVis for MatlabŪ, allowing for complex trials with many images at high resolutions.
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What are the software requirements for W4M? |
Software Requirements:
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Windows 98, 2000, XP
MatlabŪ version 6.x
DirectX 7.0 or higher |
NOTE: DirectX 7.0 or higher is required to utilize the mulitple monitor and stereo goggle features.
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Why am I seeing smiley faces on all my stimuli? |
The smiley faces are there to remind you to license your computer to use WinVis software. To license a computer, you run the License Manager (from the downloads page).
The license manager installs a special code on your computer that is later checked by WinVis software to make sure you are licensed to use that software. If you need to run WinVis software on multiple computers, you need to have multiple machine licenses.
To get more machine licenses, you can upgrade your account at the account services page. |
When I try to install WinVis For Matlab, the installer fails with the error: Either Matlab is running or you do not have permission to copy files into the destination folder. What could be wrong? |
The most common cause for this error is that you do not have permission to write to the destination folder you specified. In order to install WinVis you must have permission to create sub-folders and write files into the destination folder. This is especially true if you are trying to install into the Matlab directory on a network computer. There are two possible solutions to this problem:
Contact your network administrator and ask him/her to temporarily expand your permissions for the purposes of the installation. NOTE: You cannot simply have the administrator install the software, because the licensing information is saved for the Windows user account that actually installs the software.
Install to a directory that you are sure you have permissions to write to. Usually every user has permission to write, to the Windows Desktop.
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I have successfully Installed WinVis For Matlab, what do I do now? |
To get started, you should go through the following steps:
1. Set the Matlab Path - Start Matlab, and choose Set Path from the File Menu. (Make sure that the JVM is enabled on this version. If you do not know what this means, then ignore the previous instruction and continue). Click on Add with Subfolders and select the destination directory you specified in the installer. (By default: C:\Program Files\MatlabR12)
2. Create a shortcut to Matlab -NOJVM - Close Matlab if it still open. Create a shortcut to Matlab on the desktop. Right click on the shortcut and choose properties. In the properties dialog, add -nojvm to the target. (Make sure there is a space between matlab.exe and -nojvm).
3. Startup WinVis - Open up Matlab with your newly created shortcut. At the command prompt, type in WinVis to load the DLL. If this returns a 0, WinVis has successuflly loaded.
4. Load the Matlab M-File Editor - You may notice, that the version of Matlab that is open (without the JVM) can not make use of the m-file editor. In order to work around this, simply startup the m-file editor. To do this, browse to the Matlab folder using windows explorer. In the bin\win32 sub-folder, there is a file called meditor.exe. Run this file to load the m-file editor. When you have finished editing your scripts, simply save them and run them from the NOJVM version of Matlab (or copy and paste into the command window).
If you have any questions about this process, please do not hesitate to contact us. |
I downloaded WinVis for Matlab (or WinVis for Matlab w/ Digital/Analog IO). Do I need to download the W4M User's Manual? |
No, you don't. The User's Manual is packaged with WinVis for Matlab. After you install W4M, you can find the User's Manual in your matlab\toolbox\winvis directory. The file is called W4M_manual.pdf.
The manual is provided as a seperate download for potential users that want to read about W4M before they install it.
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Why do images in W4M look brighter than the same image when viewed through Matlab's IMAGE command? |
| The Matlab IMAGE command expects floating point data on the range of [0.0, 1.0], while W4M expects floating point data on the range of [-1.0, 1.0]. Thus a pixel with intensity (0.5, 0.5, 0.5) is 50% gray in Matlab, but in W4M it is 75% gray. |
Why does Matlab returns an error saying "Undefined function or variable 'WinVis'" when I try to initialize the WinVis system? |
Your Matlab path may be set incorrectly. In Matlab 6.x, go the file menu and select set path. One of the directories listed in the path should the WinVis toolbox directory (i.e. MatlabR12/toolbox/WinVis). If it is not listed there, add this entry, and try to load WinVis again.
NOTE: If you have recently installed a new toolbox from MathWorks, your path may have been reset. You may have to add the WinVis directory again. |
How can I integrate my stimuli from the online tools with W4M? |
Stimuli created through the online Stimulus Generator can be used in W4M by downloading Matlab extension DLLs. To create a Matlab extension DLL, select compile from the Stimulus Editor interface. Choose the radio button next to "Compile As a Matlab Extension DLL" and press compile. When the save dialog appears, save the dll to the same directory as your winvis DLL (default is MatlabRoot/toolbox/WinVis).
In the Matlab Command Window, type in 'WinVis' to load the W4M DLL, and begin defining your trial as you normally would. To load your stimulus, type in
img1 = StimulusName('default', monitorNum);
where StimulusName is the name of your stimulus, and monitorNum is the id for the monitor used in the trial. This will generate your stimulus with its default parameters. Alternatively, you may generate the stimulus with non-default parameters by typing
img1 = StimulusName('params', param1, param2,..., monitorNum);
where StimulusName is the name of your stimulus, paramN is the value for the Nth parameter, and monitorNum is the id for the monitor used in the trial. The images that are produced by these calls are floating point matrices with value ranging from -1.0 (no intensity) to 1.0 (full intensity). Values that were designated as either the background or NO_VALUE in the online system will appear as Not-A-Number (NaN) in Matlab. Before loading your image into W4M, you must remove all NaN values and scale the matrix to have values ranging from 0 to 255.
Since all of the NaN values represent areas of the image that are supposed to be transparent, we suggest using a mask and matrix arithmatic to replace the NaN values with the appropriate portions of the background. The following Matlab code block gives an example of how to do this:
| % Assume your background is stored in a variable named 'bg'
windowX = 300; % xExtent of the trial window
windowY = 300; % yExtent of the trial window
originX = 100; % xOrigin of the trial window
originY = 100; % yOrigin of the trial window
img = StimulusName('default', 1); % generate the stimulus
mask = isnan(img); % generate a mask for all NaN values
img(find(mask)) = 0; % set all NaN values to 0
img = (mask .* bg) + (img .* (1-mask)); % use the mask to combine the background and image. |
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