Forced Choice Subjective Experiment
The FC protocol displays 6 images.
Three original images are displayed on the upper part of the screen, whereas
three distorted images are shown in the lower half of the monitor.
The same distortion parameters applies to all three images.
The index of the current image is shown on top of the page.
The observer is asked to select the correct corresponding pair of images.
On image (and only one) is present both in the upper and lower parts.
The observers must click on the original images on top, and then click on
the corresponding distorted image at the bottom.
A selection is mandatory, this is a forced choice protocol.
This is a modified 2AFC protocol.
There are no restrictions on the display time.
Test conditions:
At the beginning of the subjective experiment, the observer is asked
for his name.
The test duration varies according to the number of displayed images.
The playlist can be seen here:
http://websubjexp.polytech.univ-nantes.fr/FCexp3/playlist_dist.txt
The observers should remain seated at the same distance from the screen
during all the test duration.
The viewing distance should be approximately 6 times the height of the
displayed images.
Once the experiment is finished, the observer can access the resulting
scores here:
http://websubjexp.polytech.univ-nantes.fr/FCexp3/data/Scores_<NAME>.txt
The log gives the image number (in the first column), the position (1 to 3)
of the original image on top, and the position (1 to 3 again) of the
selected image.
The same line is repeated for the distorted image; i.e. we have the position
(1 to 3) of the correct distorted image in the lower half of the screen, and
the position (1 to 3 again) of the selected image.
Observers can run the experiment more than once, the collected scores will
thus be appended in the results file.