Forced Choice Subjective Experiment
The FC protocol displays 4 images.
The distorted image being evaluated is placed on the bottom part of the screen, along with 2 other distorted images (with the same distortion parameters).
On the upper part of the screen, an original image is shown.
The index of the current image is shown on top of the page.
The observer is asked to select the distorted image in the lower panel corresponding to the original image (on top).
The observers must click on one of the images.
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/FCexp2/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/FCexp/data/Scores_<NAME>.txt
Besides the image name (within the first column), the second column gives the position of the corresponding original image,
the third column shows the position of the image being selected by the observer, and finally,
the last column gives either a 1 for a correct designation of the distorted image or a 0 when the distorted image couldn't be found.
Observers can run the experiment more than once, the collected scores will thus be appended in the results file.