Afterimage appears at image offset


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KatrinaMcDonough
KatrinaMcDonough
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Group: Forum Members
Posts: 45, Visits: 235
Hello, 
I have a task that shows a brief flickering stimulus (mask) over the top of another image (hand).  At mask offset, there is a box around the mask stimuli that flashes on the screen. Do you know what causes this afterimage and how to remove it?
Thanks

<picture hand>
/ erase = false
/ items = ("hand.jpg")
/ size = (80%, 80%)
/ position = (50%, 50%)
</picture>

<picture mask1>
/ items = ("Mask01.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<picture mask2>
/ items = ("Mask02.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<picture mask3>
/ items = ("Mask03.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<trial action>
/ stimulusframes = [1= hand, mask1; 6= hand, mask2; 11=hand, mask3; 21= hand, mask1; 26= hand, mask2; 31= hand, mask3;
                    36= hand, mask1; 41= hand, mask2; 46= hand, mask3; 51= hand, mask1; 56= hand, mask2; 61= hand, mask3]
/ response = noresponse
</trial>

<trial response>
/ stimulusframes = [1= hand]
/ inputdevice = keyboard
/ validresponse = (57)
</trial>

<block test>
/ trials = [1= action; 2 = response]
</block>

<expt expt>
/ blocks = [1-10 = test]
</expt>
Attachments
hand.jpg (176 views, 71.00 KB)
Mask01.png (174 views, 3.00 KB)
Mask02.png (171 views, 3.00 KB)
Mask03.png (177 views, 3.00 KB)
Dave
Dave
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Group: Administrators
Posts: 12K, Visits: 98K
KatrinaMcDonough - 10/2/2020
Hello, 
I have a task that shows a brief flickering stimulus (mask) over the top of another image (hand).  At mask offset, there is a box around the mask stimuli that flashes on the screen. Do you know what causes this afterimage and how to remove it?
Thanks

<picture hand>
/ erase = false
/ items = ("hand.jpg")
/ size = (80%, 80%)
/ position = (50%, 50%)
</picture>

<picture mask1>
/ items = ("Mask01.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<picture mask2>
/ items = ("Mask02.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<picture mask3>
/ items = ("Mask03.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<trial action>
/ stimulusframes = [1= hand, mask1; 6= hand, mask2; 11=hand, mask3; 21= hand, mask1; 26= hand, mask2; 31= hand, mask3;
                    36= hand, mask1; 41= hand, mask2; 46= hand, mask3; 51= hand, mask1; 56= hand, mask2; 61= hand, mask3]
/ response = noresponse
</trial>

<trial response>
/ stimulusframes = [1= hand]
/ inputdevice = keyboard
/ validresponse = (57)
</trial>

<block test>
/ trials = [1= action; 2 = response]
</block>

<expt expt>
/ blocks = [1-10 = test]
</expt>

Stimuli are erased at the end of the trial by default. That is what the "box" is. Set /erase = false in your <picture> elements and it will be gone.

KatrinaMcDonough
KatrinaMcDonough
Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)Partner Member (576 reputation)
Group: Forum Members
Posts: 45, Visits: 235
Dave - 10/2/2020
KatrinaMcDonough - 10/2/2020
Hello, 
I have a task that shows a brief flickering stimulus (mask) over the top of another image (hand).  At mask offset, there is a box around the mask stimuli that flashes on the screen. Do you know what causes this afterimage and how to remove it?
Thanks

<picture hand>
/ erase = false
/ items = ("hand.jpg")
/ size = (80%, 80%)
/ position = (50%, 50%)
</picture>

<picture mask1>
/ items = ("Mask01.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<picture mask2>
/ items = ("Mask02.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<picture mask3>
/ items = ("Mask03.png")
/ size = (20%, 20%)
/ position = (80%, 50%)
</picture>

<trial action>
/ stimulusframes = [1= hand, mask1; 6= hand, mask2; 11=hand, mask3; 21= hand, mask1; 26= hand, mask2; 31= hand, mask3;
                    36= hand, mask1; 41= hand, mask2; 46= hand, mask3; 51= hand, mask1; 56= hand, mask2; 61= hand, mask3]
/ response = noresponse
</trial>

<trial response>
/ stimulusframes = [1= hand]
/ inputdevice = keyboard
/ validresponse = (57)
</trial>

<block test>
/ trials = [1= action; 2 = response]
</block>

<expt expt>
/ blocks = [1-10 = test]
</expt>

Stimuli are erased at the end of the trial by default. That is what the "box" is. Set /erase = false in your <picture> elements and it will be gone.

This worked great, thanks!
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