  Source camera identification is still a hard task in forensics community,
especially for the case of the small query image size. In this paper, we
propose a solution to identify the source camera of the small-size images:
content-adaptive fusion network. In order to learn better feature
representation from the input data, content-adaptive convolutional neural
networks(CA-CNN) are constructed. We add a convolutional layer in preprocessing
stage. Moreover, with the purpose of capturing more comprehensive information,
we parallel three CA-CNNs: CA3-CNN, CA5-CNN, CA7-CNN to get the
content-adaptive fusion network. The difference of three CA-CNNs lies in the
convolutional kernel size of pre-processing layer. The experimental results
show that the proposed method is practicable and satisfactory.
