1. A method for detecting a presence of an object in an image, the method comprising: receiving multiple training image samples of the object; using at least one computing device to determine a set of adaptive features for each training image sample of the object, wherein the determining includes: initializing parameters for a set of wavelets; and optimizing the set of wavelets by adapting the parameters to match one-by-one to image structures of the respective training image sample by minimizing the error between the training image sample and the set of wavelets; using at least one computing device to integrate the sets of adaptive features of the multiple training image samples to generate an adaptive feature pool; using at least one computing device to determine a general feature based on the adaptive feature pool, wherein the general feature encodes a common characteristic of all of the training image samples of the object; and using at least one computing device to examine the image using a classifier determined based on the general feature to detect the presence of the object.