PIP-MM: Pre-Integrating Prompt Information into Visual Encoding via Existing MLLM Structures

Abstract: The Multimodal LLMs (MLLMs) have activated the capabilitiesof LLMs in solving visual-language tasks by integratingvisual information. The prevailing approach in existing MLLMs involvesemploying an image encoder to extract visual features, converting thesefeatures into visual tokens via an adapter, and then integrating them with theprompt into the LLM. However, because the process of image encoding isprompt-agnostic, the extracted visual features only provide a coarsedescription of the image, impossible to focus on the requirements of theprompt. On one hand, it is easy for image features to lack information aboutthe prompt-specified objects, resulting in unsatisfactory responses. On theother hand, the visual features contain a large amount of irrelevantinformation, which not only increases the burden on memory but also worsens thegeneration effectiveness. To address the aforementioned issues, we propose\textbf{PIP-MM}, a framework that \textbf{P}re-\textbf{I}ntegrates\textbf{P}rompt information into the visual encoding process using existingmodules of MLLMs. Specifically, We utilize the frozen LLM in the MLLM tovectorize the input prompt, which summarizes the requirements of the prompt.Then, we input the prompt vector into our trained Multi-Layer Perceptron (MLP)to align with the visual input requirements, and subsequently replace the classembedding in the image encoder. Since our model only requires adding atrainable MLP, it can be applied to any MLLM. To validate the effectiveness ofPIP-MM, we conducted experiments on multiple benchmarks. Automated evaluationmetrics and manual assessments demonstrate the strong performance of PIP-MM.Particularly noteworthy is that our model maintains excellent generationresults even when half of the visual tokens are reduced.