# Color Texture Image Complexity--EEG-Sensed Human Brain Perception vs. Computed Measures
## 7 Experimental Results  
### Subjective Experiment Analysis  
The memory test results comprise about a 65 to 95% success rate, with an average of 84.38%, suggesting that participants were highly attentive during the experiment. The error rate is explainable, being related to the percentage of highly confoundable images (specifically, 30% of the images chosen for the test were highly similar and easily confoundable, such as they visually look alike, with some differences in small details).  
The main complexity criteria were extracted from subjective participants responses and they are presented in Table 1. The most frequent criteria used are represented by the image properties, such as color, followed by texture distribution characteristics, such as structure type & forms, positioning, details, repeatability, disorder vs. order, no. of elements, content type, complemented with effects of visualisation, such as clarity vs. blurry, contrast. Further, we noted the distinctive criteria used, specific to an extension of the texture content beyond the image itself represented by impulse, sensations (3D, tactile), or the induced mood, emotions, memories, and imagination. Up to 50% of participants mentioned criteria relating to their interpretation, sensations, emotions, ans imagination that cannot be described by mathematical or image texture analysis measures. Therefore, considering human interpretation when expressing and analyzing texture is of great importance, since these aspects can drastically influence the complexity perception, as we will see in the following analysis Section 7.2.  
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline
**Complexity Criteria** & **P1** & **P2** & **P3** & **P4** & **P5** & **P6** & **P7** & **P8** & **Total (\%)** \\ \hline
**colors** & x & x & x & x & x & x & x & x & **100\%** \\ \hline
**type of structure \& forms:** simple, geometrical, fragmentation, & & & & & & & & & & \\ granularity, rugosity vs. smoothness, homogeneity, uniformity & x & x & x & x & x & x & x & x & **87.5\%** \\ \hline
**distribution \& positioning:** crowdedness, sparsity, & & x & x & x & x & x & x & **75\%** \\ scattering, spreading & & x & x & x & x & x & x & x & **75\%** \\ \hline
**details** & x & & x & x & x & x & x & x & **75\%** \\ \hline
**repeatability,** resemblance, similarity **vs variety** & x & & x & x & x & x & x & **75\%** \\ \hline
**clarity,** sharpness, accentuation, focus, delimited forms **vs blurry** & x & x & x & x & x & x & x & **75\%** \\ \hline
**disorder,** randomness, chaos, mixture, intercalation, twistedness **vs. order**, balance & x & x & x & x & x & x & x & **75\%** \\ \hline
**no. of elements,** groups, regions & & x & x & x & x & x & & **62.5\%** \\ \hline
**impulse type**: first impression, attraction, captivation, interest & x & & x & x & x & & 50\% \\ \hline
**contrast, luminosity, intensity, darkness vs. shadows, light & x & & x & x & & & & 37.5\% \\ \hline
**size:** big vs. small, **expansion,** vastity (beyond the image capture) & x & & x & x & & & 37.5\% \\ \hline
**recognition, understandability,** difficulty in recognition and reasoning & x & & x & & & & & 25\% \\ \hline
**mood induced**: pleasant, relaxing vs. tiring, monotonous & x & & x & x & x & 37.5\% \\ \hline
**sensations**: 3D & x & x & & & & & 25\% \\ \hline static vs. dynamic & & & & & & & & 12.5\% \\ \hline zoom-in/out & & & x & & & & & 12.5\% \\ \hline tactile & & & & x & & & & 12.5\% \\ \hline
**content type**: familiar, common/ordinary & & & x & & & & & 12.5\% \\ \hline
**human specific capabilities**: emotions, memories, imagination & x & & & & & 12.5\% \\ \hline
**hardness in construction** & & & x & & & & & & \\ \hline \hline \end{tabular}  
* Primary criteria and significant contributions are highlighted in bold.  
\end{table}
Table 1: Complexity factors.