This paper introduces an algorithm for fast and subpixel precise detection of small, compact image primitives (”blobs”). The algorithm is based on differential geometry and incorporates a complete scale-space description. Hence, blobs of arbitrary size can be extracted by just adjusting the scale parameter. In addition to center point and boundary of a blob, also a number of attributes are extracted. These describe the specific blob characteristics in more detail and, thus, allow for a subsequent classification of blobs. Several examples on real images illustrate the performance of the proposed algorithm.