Novel Methods for the Visualization and Analysis of Functional Maps in Cortex

Results 161 7.2 Artificial Image Data Artificial phase images were created to demonstrate the feasibility of the matching strategy used by mrFindBorders. The same function as for the creation of the atlases was used to make the artificial phase images for a flickering rotating wedge visual stimulus and a flickering ex- panding ring visual stimulus. The images were rotated, noise was introduced by calling the function vAddNoiseTo- PhIm as explained in section 6.17 (zero mean and variance of 0.1; the values were determined by visual inspection of the resulting images), and the atlases were manually deformed by as- signing displacement values to some control points. In mrFindBorders, the artificial phase im- ages were then used instead of measured images. Initial atlases were made based on three points specified by the user⁹. The registration algorithm was applied to fit the initial phase-wedge atlas to the corre- sponding artificial phase image. Two iterations were done on very-low-resolution images, three iterations on low-resolution images, and two iterations on high-resolution images. 9 The data can be found in the file DA_Validation_Artificial_1Dir 2 3 2.mat.