1. An image processing apparatus for setting image process parameters to be used in an image recognition process of detecting an object from an input image, comprising: a learning unit configured to create a dictionary for detection of the object from an image obtained by performing an image process, which depends on a first image process parameter, on a training image of a detection target object; a detection unit configured to detect the object based on the dictionary from a photographed image including the image of the object; a first determination unit configured to determine the dictionary created based on the image process depending on the first image process parameter, based on a detection result that the detection unit detects the object from an image obtained by performing an image process, which depends on the first image process parameter, on the photographed image; and a second determination unit configured to determine a second image process parameter, based on a detection result that the detection unit using the determined dictionary detects the object from an image obtained by performing an image process, which depends on the second image process parameter, on the photographed image.