Computational Intelligence and Neuroscience

Research Article

The Role of Visual Features in Text-Based CAPTCHAs: An fNIRS Study for Usable Security

Table 4

Significant contrast results following the three-way interaction between line, wave, and rotation for HbO measurements.


Optode	Source	Line	Wave	Rotation	Type III SS	df	MS	F		Partial η²

1	Line wave rotation	Linear	Linear	Linear	0.568	1	0.568	5.428	0.031	0.222
	Line wave rotation	Quadratic	Linear	Linear	0.833	1	0.833	6.149	0.023	0.245
	Error	Linear	Linear	Linear	1.989	19	0.105
	Error	Quadratic	Linear	Linear	2.573	19	0.135

2	Line wave rotation	Linear	Linear	Linear	0.568	1	0.568	4.293	0.051	0.177
2	Error	Linear	Linear	Linear	2.646	20	0.132

3	Line wave rotation	Linear	Linear	Linear	0.466	1	0.466	5.909	0.025	0.228
3	Error	Linear	Linear	Linear	1.576	20	0.079

4	Line wave rotation	Linear	Linear	Linear	0.584	1	0.584	4.374	0.051	0.196
	Line wave rotation	Quadratic	Linear	Linear	0.688	1	0.688	5.139	0.036	0.222
	Error	Linear	Linear	Linear	2.404	18	0.134
	Error	Quadratic	Linear	Linear	2.411	18	0.134

9	Line wave rotation	Quadratic	Linear	Linear	0.711	1	0.711	6.563	0.019	0.247
9	Error	Quadratic	Linear	Linear	2.167	20	0.108

10	Line wave rotation	Quadratic	Linear	Linear	0.763	1	0.763	4.607	0.045	0.195
10	Error	Quadratic	Linear	Linear	3.145	19	0.166

11	Line wave rotation	Linear	Linear	Linear	0.534	1	0.534	5.34	0.032	0.211
	Line wave rotation	Quadratic	Linear	Linear	0.627	1	0.627	4.794	0.041	0.193
	Error	Linear	Linear	Linear	1.999	20	0.1
	Error	Quadratic	Linear	Linear	2.617	20	0.131

12	Line wave rotation	Linear	Linear	Linear	0.543	1	0.543	6.202	0.023	0.256
12	Error	Linear	Linear	Linear	1.576	18	0.088

13	Line wave rotation	Linear	Linear	Linear	0.621	1	0.621	5.366	0.032	0.22
13	Error	Linear	Linear	Linear	2.198	19	0.116

14	Line wave rotation	Linear	Linear	Linear	0.965	1	0.965	8.218	0.011	0.339
14	Error	Linear	Linear	Linear	1.878	16	0.117

15	Line wave rotation	Linear	Linear	Linear	0.676	1	0.676	8.225	0.012	0.354
15	Error	Linear	Linear	Linear	1.232	15	0.082

16	Line wave rotation	Linear	Linear	Linear	0.825	1	0.825	8.038	0.010	0.287
	Line wave rotation	Quadratic	Linear	Linear	0.23	1	0.23	3.652	0.070	0.154
	Error	Linear	Linear	Linear	2.052	20	0.103
	Error	Quadratic	Linear	Linear	1.26	20	0.063