A viscometer, comprising: a source of fluid pressure, a tube, an array of optical detectors, an acquisition driver circuit and viscosity computation logic. The tube has an inside volume that is hydraulically responsive to the source of fluid pressure. The array of optical detectors is positioned along a length of the first tube with a plurality of its detectors optically responsive to the inside volume of the first tube and including an image data output. The acquisition driver circuit is responsive to the image data output of the first array to acquire a series of successive images of the inside volume of the first tube. The viscosity computation logic is responsive to the acquisition driver circuit and operative to compute the viscosity of a fluid flowing along the first tube from the series of images of the inside volume of the first tube.