Modification of watershed transformation for images, containing small objects

We present a new method, which allows successful application of watershed transformation for images containing small objects. The method can be divided into two stages. During the first stage of segmentation a special gradient operator is applied to get the gradient of the image. It gives us a possibility to increase the resolution of the gradient doubly in comparison with the resolution of the original image. We can achieve this by approximation of the first-order derivative not only in image pixels, but also between pixels. During the second stage the author´s modification of watershed transformation is applied. This modification enables us make optimal use of the image gradient obtained at the first stage. The method to be introduced was probed on a large amount of images with small details, and showed better results than the traditional watershed algorithm.