Subjective Camera: Bridging Human Cognition and Visual Reconstruction through Sequence-Aware Sketch-Guided Diffusion

Abstract: We propose Subjective Camera, a human-as-imaging-device paradigm that reconstructs real-world scenes from mental impressions through synergistic use of verbal descriptions and progressive rough sketches. This approach overcomes dual limitations of language ambiguity and sketch abstraction by treating the user's drawing sequence as priors, effectively translating subjective perceptual expectations into photorealistic images. Existing approaches face three fundamental barriers: (1) user-specific subjective input biases, (2) huge modality gap between planar sketch and 3D priors in diffusion, and (3) sketch quality-sensitive performance degradation. Current solutions either demand resource-intensive model adaptation or impose impractical requirements on sketch precision. Our framework addresses these challenges through concept-sequential generation. (1) We establish robust appearance priors through text-reward optimization, and then implement sequence-aware disentangled generation that processes concepts in sketching order; these steps accommodate user-specific subjective expectation in a train-free way. (2) We employ latent optimization that effectively bridges the modality gap between planar sketches and 3D priors in diffusion. (3) Our hierarchical reward-guided framework enables the use of rough sketches without demanding artistic expertise. Comprehensive evaluation across diverse datasets demonstrates that our approach achieves state-of-the-art performance in maintaining both semantic and spatial coherence.