Defining Borders 1.1 2007/12/19 18:31:19.730 US/Central 2007/12/19 18:33:02.081 US/Central Thomas Yeh tyeh@rice.edu Thomas Yeh tyeh@rice.edu

Defining Borders

Overview With the original cell picture, as shown below, it is very difficult to make out the cell borders due to the lack of contrast between the borders and the background of the image. Our first goal, before edge detection can even be done, is to create a sharper contrast between the borders and the background. This is shown in Figure 1.

Thresholding In order to create a higher contrast between a cell’s borders and the background, thresholding was utilized. Pixels of lower intensities, the background, were thrown out while pixels of higher intensities were kept. The IMADJUST command in Matlab allowed us to specify a threshold intensity and mapped all pixels below the threshold to zero. The result can be seen in Figure 2.