Kingfisher: Fast Personalized Visual Autoregressive Generation via Scale-Aware Prompt-Conditioned Scale Decomposition
Authors: Dinh-Khoi Vo, Akihiro Sugimoto, Minh-Triet Tran, Trung-Nghia Le
Organizations: University of Science, Ho Chi Minh City, Vietnam · Vietnam National University, Ho Chi Minh City, Vietnam · National Institute of Informatics, Tokyo, Japan
Personalized image generation has been extensively studied in diffusion models, often relying on subject-specific optimization of model weights, textual embeddings, LoRA modules, or adapters. In this work, we explore a different direction for fast personalization in visual autoregressive models. Our key observation is that a short prefix of early autoregressive scale codes is sufficient to strongly determine both object structure and global appearance, while later scales primarily refine the established generation trajectory. Based on this insight, we introduce Kingfisher, a model-tuning-free framework that decomposes early residual scale codes into content- and style-related components through prompt-conditioned scale-code subspaces. Given two real images, Kingfisher first decomposes their early scale codes, then recomposes the content components of one image with the style components of the other into a compact semantic prefix. The frozen generator subsequently predicts the remaining scales through bitwise self-correction for coherent refinement. Experiments on CSD-100 show that Kingfisher achieves strong content preservation and the highest style and text alignment among the evaluated methods, while reducing pair-specific preparation time by approximately 54x compared with diffusion-based methods and 7.5x compared with VAR-based alternatives. These results demonstrate that effective personalization can be achieved by directly manipulating the native scale-space representation of a frozen visual autoregressive generator.
Figures & tables
Figure 1: Kingfisher combines the content of one real image with the appearance of another by decomposing and recomposing early autoregressive scale codes. The remaining scales are predicted by the frozen VAR generator via bit-wise self-correction, enabling fast, coherent personalization without model tuning, LoRA, adapters, or learned subject embeddings.
Figure 2: Scale-wise analysis of visual autoregressive generation. We analyze residual scales from two complementary views: prefix reconstruction and prompt routing. Prefix reconstruction shows that a short early ground-truth prefix is nearly sufficient to recover input semantics, while prompt routing shows that early scales dominate object identity, shape, color, and global appearance. Together, these results indicate that early consecutive scales form compact yet entangled semantic anchors, whereas later scales mainly refine details.
Figure 3: Overview of the Kingfisher pipeline. Given a content image A and a style image B , both are encoded into multi-scale residual codes using the frozen tokenizer. Kingfisher constructs a neutral-style affine space from neutral prompts and an object-content subspace from object-specific prompts. The selected early residual codes are decomposed into content, style, and residual factors through prompt-space constraints and recomposed into a compact semantic prefix. The frozen Infinity generator then predicts the remaining scales through bitwise self-correction, producing an output that preserves the object structure of A while adopting the visual appearance of B .
Content Align.
Style Align.
Text Align.
Method
CSD-C ↑
CLIP-I ↑
CSD-S ↑
DINO ↑
CLIP-T ↑
DreamBooth-LoRA ruiz2023dreambooth
0.5519
0.7362
0.4207
0.3813
0.2492
B-LoRA frenkel2024implicit
0.4739
0.7182
0.4990
0.4220
0.2683
UnZipLoRA liu2025unziplora
0.5782
0.7322
0.3673
0.3560
0.2472
Inspiration Tree vinker2023concept
0.5413
0.7591
0.2897
0.2601
0.2565
CSD-VAR nguyen2025csd
0.4731
0.7184
0.2812
0.2503
0.2648
Table 1: Quantitative comparison on the cross-image CSD-100 benchmark. Best results are shown in bold and second-best results are underlined .
Figure 4: Qualitative comparison on the cross-image CSD-100 benchmark nguyen2025csd . Given a content reference IA and a style reference IB , each method aims to preserve the content of IA while transferring the appearance of IB . Kingfisher achieves a favorable balance between content preservation and style transfer across diverse content–style combinations.
Efficiency
Human Evaluation
Method
Prep./pair (s) ↓
Infer./image (s) ↓
Votes ↑
Pref. ↑
DreamBooth-LoRA ruiz2023dreambooth
1542.21±38.47
11.98±0.91
54
9.0%
B-LoRA frenkel2024implicit
1309.00±27.63
12.88±1.02
168
28.0%
UnZipLoRA liu2025unziplora
3463.70±40.28
11.83±0.95
45
7.5%
Inspiration Tree vinker2023concept
7465.36±216.84
6.56±0.54
39
6.5%
CSD-VAR nguyen2025csd
171.65±11.82
1.39±0.12
40
6.7%
Table 2: Efficiency and human evaluation. Efficiency is measured on a single A100 GPU. Preparation denotes the pair-specific optimization time for one content–style pair, while inference denotes the time required to generate one image after preparation. Human preference is computed from 600 forced-choice selections.
Appendix figures & tables10 assets
Supplementary material from the paper’s appendix.
Appendix
Experiment
Range
CLIP-I ↑
DINO-I ↑
LPIPS ↓
CLIP-T ↑
DINO-P1 ↑
Prefix recon.
R1
0.42
0.36
0.58
–
–
Prefix recon.
R1:2
0.61
0.54
0.41
–
–
Prefix recon.
R1:3
0.78
0.72
0.26
–
–
Prefix recon.
R1:4
0.88
0.84
0.16
–
–
Prefix recon.
R1:7
0.93
0.89
0.11
–
–
Prompt routing
R10:13
–
–
–
0.28
0.74
Appendix
Table 3: Quantitative scale-wise analysis. Results are averaged over 100 real images and 200 prompt-routing pairs. For prefix reconstruction, CLIP-I and DINO-I measure similarity to the input image, while LPIPS measures perceptual reconstruction distance. For prompt routing, CLIP-T measures alignment with Prompt 2 , while DINO-P1 measures similarity to the all-Prompt 1 reference.
Type
Prompt template
Neutral
“a plain realistic photograph with natural colors and ordinary daylight”
“a standard documentary photograph with neutral balanced lighting”
“a clean product photograph with a simple background and natural texture”
“a realistic snapshot with balanced colors and soft natural illumination”
“a straightforward studio photograph with ordinary materials and neutral tones”
Object
“a clearly recognizable <object> ”
Appendix
Table 4: Neutral and object-conditioned prompt templates used to construct the prompt-conditioned scale subspaces.
Prefix configuration
CSD-C ↑
CLIP-I ↑
CSD-S ↑
DINO ↑
CLIP-T ↑
[A1,A2,A3,A4]
0.7774
0.9370
0.2922
0.2720
0.3017
[R1∗,A2,A3,R4∗]
0.6281
0.8392
0.4342
0.3751
0.3119
[R1∗,R2∗,A3,R4∗]
0.5504
0.7922
0.5210
0.4367
0.3127
[R1∗,R2∗,R3∗,R4∗]
0.4979
0.7416
0.6156
0.5416
0.2959
Appendix
Table 5: Ablation of early-scale prefix composition. Best results are shown in bold and second-best results are underlined.
β
CSD-C ↑
CLIP-I ↑
CSD-S ↑
DINO ↑
CLIP-T ↑
0.00
0.5436
0.7784
0.5353
0.4597
0.3068
0.25
0.5471
0.7866
0.5333
0.4521
0.3104
0.50
0.5504
0.7922
0.5210
0.4367
0.3127
0.75
0.5551
0.7968
0.5161
0.4239
0.3130
1.00
0.5613
0.8027
0.5063
0.4096
0.3144
Appendix
Table 6: Sensitivity to the structural correction coefficient β . Best results are shown in bold and second-best results are underlined.
Configuration
CSD-C ↑
CLIP-I ↑
CSD-S ↑
DINO ↑
CLIP-T ↑
w/o Lsty
0.5478
0.7895
0.4726
0.3914
0.3048
w/o Lalign
0.5127
0.7568
0.5073
0.4218
0.3035
w/o Lremove
0.5019
0.7446
0.4981
0.4127
0.3009
w/o Lrec
0.4742
0.7165
0.4386
0.3597
0.2863
w/o Lorth
0.5264
0.7698
0.4935
0.4062
0.3074
Full objective
0.5504
0.7922
0.5210
0.4367
0.3127
Appendix
Table 7: Ablation of the decomposition objective. Best results are shown in bold and second-best results are underlined.
Figure 5: Additional qualitative ablation of prefix composition. From left to right: content reference IA , style reference IB , [R1∗,A2,A3,R4∗] with β=0.5 , [R1∗,R2∗,A3,R4∗] with β=0.5 , [R1∗,R2∗,R3∗,R4∗] with β=0.5 , [R1∗,A2,A3,R4∗] with β=1.0 , [R1∗,R2∗,A3,R4∗] with β=1.0 , and [R1∗,R2∗,R3∗,R4∗] with β=1.0 .
Figure 6: Visualization of style removal. Each pair shows an input image and the corresponding style-removed result R−S . The operation suppresses appearance-specific information while retaining the underlying object content and structure.
Figure 7: Additional qualitative comparison with prior methods. Given a content reference IA and a style reference IB , we compare Kingfisher with the evaluated baselines across additional content–style combinations.
Figure 8: Qualitative results of Kingfisher on CSD-100. Each example shows the content reference IA , the style reference IB , and the corresponding Kingfisher output.
Figure 9: Challenging cases with abstract or ambiguous style references. When the style reference contains weak, highly abstract, or insufficiently distinctive visual cues, its appearance is difficult to isolate from a single image. Consequently, both existing baselines and Kingfisher may exhibit weaker or less consistent style transfer.