A device for performing an immunoassay of analytes in a sample, the device comprising: a membrane including a first site, a second site laterally separated from the first site and multiple spots arranged between the first site and the second site, each spot including binding molecules for selectively binding the analytes at the corresponding spot; a liquid phase configured to carry the sample and labels for optically signaling the presence of the analytes, and to laterally flow from the first site across the spots to the second site; an image acquisition unit configured to acquire a sequence of images, wherein each image captures the multiple spots, and the sequence of images is indicative of optical signals from the labels at different points in time during the lateral flow; and a controller coupled to the image acquisition unit and configured to analyze the sequence of images during the lateral flow by extracting signal features of each of the multiple spots for each of the points in time of the sequence, determining parameters of at least one signal model for each of the multiple spots based on the extracted signal features of the corresponding spot and comparing the parameters with one or more threshold values, (i) wherein a hydrodynamic correlation between signals from different spots is compensated using the temporal sequence of images, the hydrodynamic correlation comprising spots in the direction of the lateral flow downstream of other spots receiving less analytes than the other spots, the controller assigning correspondingly lower threshold values to downstream spots to compensate such a geometrically caused gradient in the concentration of one or more of the analytes, and/or (ii) wherein the controller is further configured to scale the threshold values by weighting factors assigned to each of the spots, wherein different weighting factors are assigned to compensate different flow rates or different velocities of the liquid phase. a membrane including a first site, a second site laterally separated from the first site and multiple spots arranged between the first site and the second site, each spot including binding molecules for selectively binding the analytes at the corresponding spot; a liquid phase configured to carry the sample and labels for optically signaling the presence of the analytes, and to laterally flow from the first site across the spots to the second site; an image acquisition unit configured to acquire a sequence of images, wherein each image captures the multiple spots, and the sequence of images is indicative of optical signals from the labels at different points in time during the lateral flow; and a controller coupled to the image acquisition unit and configured to analyze the sequence of images during the lateral flow by extracting signal features of each of the multiple spots for each of the points in time of the sequence, determining parameters of at least one signal model for each of the multiple spots based on the extracted signal features of the corresponding spot and comparing the parameters with one or more threshold values, (i) wherein a hydrodynamic correlation between signals from different spots is compensated using the temporal sequence of images, the hydrodynamic correlation comprising spots in the direction of the lateral flow downstream of other spots receiving less analytes than the other spots, the controller assigning correspondingly lower threshold values to downstream spots to compensate such a geometrically caused gradient in the concentration of one or more of the analytes, and/or (ii) wherein the controller is further configured to scale the threshold values by weighting factors assigned to each of the spots, wherein different weighting factors are assigned to compensate different flow rates or different velocities of the liquid phase. (i) wherein a hydrodynamic correlation between signals from different spots is compensated using the temporal sequence of images, the hydrodynamic correlation comprising spots in the direction of the lateral flow downstream of other spots receiving less analytes than the other spots, the controller assigning correspondingly lower threshold values to downstream spots to compensate such a geometrically caused gradient in the concentration of one or more of the analytes, and/or (ii) wherein the controller is further configured to scale the threshold values by weighting factors assigned to each of the spots, wherein different weighting factors are assigned to compensate different flow rates or different velocities of the liquid phase.