The exposure control of wafer motion imaging systems greatly affects image quality. Traditional spatial domain-based algorithms are complex and overlook differences in die features， causing uneven exposure. To solve this， we propose a method using frequency domain evaluation through image partitioning. This method uses a block-based dual-threshold segmentation algorithm to adaptively segment image features. By combining high-pass filtering with a Gaussian pyramid algorithm， it efficiently extracts high-frequency information. A region-weighted evaluation function is crafted to evaluate uniform exposure effects. Furthermore， a decision tree-based search algorithm with variable steps is introduced to quickly find optimal exposure parameters. Experiments show this algorithm improves image quality by 1.34% and reduces exposure adjustment time by 61.3%， ensuring fast imaging quality in wafer motion imaging.