This paper describes various innovative algorithms for the on-line estimation of the image jacobian, a matrix which linearly relates joint velocity and image feature velocity. We have applied them successfully to the static visual control of an uncalibrated 3 DOF joint system, using two weakly calibrated fixed cameras. The proposed algorithms prove to be particularly robust when image features are calculated with an average level of noise, and our results are clearly better than those obtained for already existing algorithms in specialized literature. © Springer-Verlag Berlin Heidelberg 2005.