Multi-teacher knowledge distillation based on joint Guidance of Probe and Adaptive Corrector.

Abstract

Knowledge distillation (KD) has been widely used in model compression. But, in the current multi-teacher KD algorithms, the student can only passively acquire the knowledge of the teacher's middle layer in a single form and all teachers use identical a guiding scheme to the student. To solve these problems, this paper proposes a multi-teacher KD based on joint Guidance of Probe and Adaptive Corrector (GPAC) method. First, GPAC proposes a teacher selection strategy guided by the Linear Classifier Probe (LCP). This strategy allows the student to select better teachers in the middle layer. Teachers are evaluated using the classification accuracy detected by LCP. Then, GPAC designs an adaptive multi-teacher instruction mechanism. The mechanism uses instructional weights to emphasize the student's predicted direction and reduce the student's difficulty learning from teachers. At the same time, every teacher can formulate guiding scheme according to the Kullback-Leibler divergence loss of the student and itself. Finally, GPAC develops a multi-level mechanism for adjusting spatial attention loss. this mechanism uses a piecewise function that varies with the number of epochs to adjust the spatial attention loss. This piecewise function classifies the student' learning about spatial attention into three levels, which can efficiently use spatial attention of teachers. GPAC and the current state-of-the-art distillation methods are tested on CIFAR-10 and CIFAR-100 datasets. The experimental results demonstrate that the proposed method in this paper can obtain higher classification accuracy.