An image processing system includes a memory storing a training image set and a reference image set, and a processor including hardware. The processor is configured to: generate an augmented image set by applying data augmentation to images included in the training image set; and determine an augmentation parameter based on a similarity between an augmentation feature statistic and a reference feature statistic, the augmentation feature statistic being a statistic of a feature of a recognition target calculated based on the augmented image set, the reference feature statistic being a statistic of a feature of the recognition target calculated based on the reference image set.