A method for estimating a crowd count of a crowd comprising: modeling performance of each of a plurality of crowd estimation techniques at different crowd levels and/or at different locations, by determining at least one of an error of crowd counting and a standard deviation of an error distribution of crowd counting, the plurality of crowd estimation techniques being techniques for estimating a crowd density of the crowd and discovering the number of humans in the crowd; receiving an image of the crowd; dividing the image of the crowd into a plurality of sub-regions, selecting one or more of the plurality of crowd estimation techniques in response to the performance modeling of the one or more of the plurality of crowd estimation techniques and an estimated crowd level and/or an estimated location, wherein selecting one or more of the plurality of crowd estimation techniques comprises selecting one or more of the plurality of crowd estimation techniques for each of the plurality of sub-regions in response to the performance modeling of the one or more of the plurality of crowd estimation techniques and an estimated crowd level and/or an estimated location for the one of the plurality of sub-regions; and estimating a crowd count of the crowd in the received image in accordance with the selected one or more of the plurality of crowd estimation techniques, wherein estimating the crowd count of the crowd in the received image comprises: estimating the crowd count of the crowd in each of the plurality of sub-regions in accordance with the selected one or more of the plurality of crowd estimation techniques for that one of the plurality of sub-regions; and combining the estimated crowd counts for each of the plurality of sub-regions to obtain the estimated crowd count of the crowd in the received image. modeling performance of each of a plurality of crowd estimation techniques at different crowd levels and/or at different locations, by determining at least one of an error of crowd counting and a standard deviation of an error distribution of crowd counting, the plurality of crowd estimation techniques being techniques for estimating a crowd density of the crowd and discovering the number of humans in the crowd; receiving an image of the crowd; dividing the image of the crowd into a plurality of sub-regions, selecting one or more of the plurality of crowd estimation techniques in response to the performance modeling of the one or more of the plurality of crowd estimation techniques and an estimated crowd level and/or an estimated location, wherein selecting one or more of the plurality of crowd estimation techniques comprises selecting one or more of the plurality of crowd estimation techniques for each of the plurality of sub-regions in response to the performance modeling of the one or more of the plurality of crowd estimation techniques and an estimated crowd level and/or an estimated location for the one of the plurality of sub-regions; and estimating a crowd count of the crowd in the received image in accordance with the selected one or more of the plurality of crowd estimation techniques, wherein estimating the crowd count of the crowd in the received image comprises: estimating the crowd count of the crowd in each of the plurality of sub-regions in accordance with the selected one or more of the plurality of crowd estimation techniques for that one of the plurality of sub-regions; and combining the estimated crowd counts for each of the plurality of sub-regions to obtain the estimated crowd count of the crowd in the received image. estimating the crowd count of the crowd in each of the plurality of sub-regions in accordance with the selected one or more of the plurality of crowd estimation techniques for that one of the plurality of sub-regions; and combining the estimated crowd counts for each of the plurality of sub-regions to obtain the estimated crowd count of the crowd in the received image.