Image segmentation is to separate an image into distinct homogeneous regions belonging to different objects. It is an essential step in image analysis and computer vision. This paper compares some segmentation technologies and attempts to find an automated way to better determine the parameters for image segmentation, especially the connectivity value of λ in λ-connected segmentation. Based on the theories on the maximum entropy method and Otsu’s minimum variance method, we propose:(1)maximum entropy connectedness determination: a method that uses maximum entropy to determine the best λ value in λ-connected segmentation, and (2) minimum variance connectedness determination: a method that uses the principle of minimum variance to determine λ value. Applying these optimization techniques in real images, the experimental results have shown great promise in the development of the new methods. In the end, we extend the above method to more general case in order to compare it with the famous Mumford-Shah method that uses variational principle and geometric measure.