Eulerian video amplification boosts sub-pixel motion by band-pass filtering per-pixel intensity traces and applying a uniform gain. That gain ignores local structure, so sensor noise is amplified together with the signal, especially in textureless regions where the monogenic phase is unreliable. We propose FrAM (Fractional-order Adaptive Motion Magnification), a pipeline developed first offline and then as a causal stream. It replaces the constant temporal gain with a Grünwald--Letnikov derivative of fractional order, giving continuous control over high-frequency emphasis, and replaces the uniform spatial gain with a per-pixel weight derived from the local amplitude of the monogenic signal. On a controlled synthetic sequence split into textured and flat halves, FrAM matches the amplification of the Eulerian baseline while keeping flat-region temporal noise at the input level. The reduction holds across an eightfold range of input noise levels. Real videos show improved spatial selectivity and lower background noise in every case. The causal reformulation cuts the per-frame cost by two orders of magnitude, reaching 69,fps at 640×480.
Figures & tables
Fig. 1: Left: magnitude of the Grünwald–Letnikov response ( 4 ), showing the continuous interpolation between the identity ( ν=0 ) and a first derivative ( ν=1 ). Right: decay of the coefficients wk as a function of memory lag k ; smaller ν implies a longer effective memory. Here k indexes past frames in the GL sum and measures the operator’s temporal reach, not a group-delay or control-loop reaction lag.
Fig. 2: Motivation for the adaptive gain. The input (left) is textured on the left half and flat on the right. Local phase (third panel) is noise in the flat region, where amplitude vanishes; the reliability mask ( 6 ) (right) identifies this without supervision.
Fig. 3: End-to-end data flow of FrAM for one pyramid band ℓ . The loop over bands runs independently for every scale, and the low-pass residual bypasses it completely. After the temporal stack S the pipeline splits into a temporal/frequency branch that produces the fractionally differentiated signal S~t , and a spatial branch computed once from the band’s temporal mean that produces the static gain map αeff ; the two are fused with the original unfiltered band. Stages with both offline and causal realisations are annotated with both modes (Sec. VII, Appendix A ).
Method
α
Amplif.
Noise
Noise
SNR
(flat)
(textured)
(dB)
Input (unprocessed)
–
1.01 ×
0.0565
0.0569
8.86
EVM (Butterworth)
20
18.44 ×
0.1137
0.1589
11.99
FrAM ( ν=0.0 )
42
17.03 ×
0.0574
0.1525
11.89
FrAM ( ν=0.3 )
64
16.09 ×
0.0574
0.1589
11.91
FrAM ( ν=0.5 )
90
14.83 ×
0.0575
0.1733
11.74
TABLE I: Comparison with α calibrated toward equal effective amplification (EVM 18.44× ), σin=0.04 . FrAM falls slightly short of the EVM factor because the reliability mask withholds gain in the flat half; lower noise is better. Bold marks the better value of each metric column among the processed methods (noise, SNR); the amplification serves as the calibration target, and the unprocessed input is listed for reference only.
Order
Gain
Amplif.
Noise (flat)
Noise (textured)
ν=0.0
constant
18.44 ×
0.1137
0.1589
ν=0.0
adaptive
8.75 ×
0.0569
0.0925
ν=0.5
constant
10.05 ×
0.0935
0.1188
ν=0.5
adaptive
4.11 ×
0.0567
0.0723
ν=0.7
constant
6.70 ×
0.0876
0.1072
ν=0.7
adaptive
2.81 ×
0.0566
0.0679
TABLE II: Adaptive-gain ablation, α=20 fixed. Within each order, bold marks the gain with the lower noise in each noise column. At fixed α the adaptive gain always lowers noise and always lowers amplification; matching amplification requires recalibrating α (Table I ).
σin
EVM
FrAM
Amplif.
Noise (flat)
Amplif.
Noise (flat)
0.01
19.15 ×
0.0284
16.81 ×
0.0142
0.02
18.98 ×
0.0569
16.64 ×
0.0284
0.04
18.44 ×
0.1137
16.09 ×
0.0574
0.08
16.64 ×
0.2275
14.36 ×
0.1207
TABLE III: Robustness to input noise, at matched amplification, ν=0.3 . Bold marks the lower flat-region noise of the two methods on each row; the amplification columns record the calibration target, not a quantity to maximise.
Fig. 4: Comparison at equal effective amplification. Top: spatio-temporal slices; right of the dashed line the region is flat, and the baseline has filled it with spurious texture that FrAM leaves untouched. Bottom left: injected noise per column, dropping sharply at the boundary for FrAM. Bottom centre: both methods track the true oscillation without phase lag. Bottom right: the trade-off controlled by ν .
Video
Method
BER
Noise
Spatial
Rate
(bg)
select.
(bpm)
face
input
0.136
0.00233
1.00
50
face
EVM
0.825
0.00909
1.40
50
face
FrAM
0.844
0.00302
4.53
50
face2
EVM
0.332
0.00702
1.14
50
face2
FrAM
0.244
0.00662
1.31
70
TABLE IV: Real video, at equal enhancement in the active region. Within each video, bold marks the better of EVM and FrAM on each metric (higher BER, lower background noise, higher spatial selectivity); EVM retains slightly higher BER on three of the four clips. The unprocessed input is shown once as a reference, and the pulse rate is a consistency check rather than a quantity to maximise.
Video
Activity
Noise (bg)
Noise (bg)
Gain
contrast
EVM
FrAM
subway
6.04
0.02026
0.00780
2.60×
face2
3.77
0.00702
0.00662
1.06×
face
1.98
0.00909
0.00302
3.01×
baby
1.07
0.00468
0.00246
1.90×
TABLE V: Activity contrast of the input against the observed advantage. Bold marks the lower background noise of the two methods on each row; the gain column is the ratio of the two noise columns. The ordering is not monotonic: contrast does not predict the margin.
Fig. 5: Real-video validation. Columns: unsupervised region masks; temporal spectrum of the active region with the target band shaded; temporal noise per region; and the difference map of injected noise (red where FrAM injects less). Red dominates on all four sequences, most clearly for face and subway .
Resolution
Offline
Streaming
Speed-up
fps
320×240
382 ms
6.3 ms
60×
158
640×480
2430 ms
14.6 ms
166×
69
1280×720
7772 ms
62.6 ms
124×
16
1920×1080
17937 ms
108.8 ms
165×
9
TABLE VI: Per-frame cost: offline versus causal streaming. Streaming is cheaper at every resolution tested; bold highlights the 640×480 row, the reference configuration quoted elsewhere in this paper.
Method
α
Amplif.
Noise (flat)
Noise (text.)
Input
–
1.01 ×
0.0565
0.0569
EVM (streaming)
20
20.85 ×
0.1605
0.2002
FrAM ( ν=0.0 )
33
20.08 ×
0.1091
0.1827
FrAM ( ν=0.15 )
39
19.78 ×
0.1149
0.1887
FrAM ( ν=0.3 )
47
19.36 ×
0.1250
0.2026
FrAM ( ν=0.5 )
64
18.47 ×
0.1480
0.2375
TABLE VII: Streaming, at equal effective amplification. Bold marks the lowest noise of each column among the processed methods; the unprocessed input is listed for reference only.
K
Amplif.
Noise (flat)
ms/frame
4
8.17 ×
0.0779
7.8
8
8.94 ×
0.0783
11.2
16
8.78 ×
0.0781
12.1
24
8.93 ×
0.0782
15.0
31
8.82 ×
0.0781
17.9
TABLE VIII: Truncating the fractional memory ( 640×480 ). Amplification and flat-region noise vary little for K≥8 , while cost grows with K ; bold highlights the truncation K=8 used by the interactive viewer.
Fig. 6: Causal reformulation. Left: per-frame cost, log scale, with the 30 fps threshold marked. Centre: truncating the fractional memory costs little amplification while cost grows with K . Right: at equal amplification in streaming, the advantage over the baseline is retained.
Video Motion Magnification (VMM) reveals imperceptible dynamics but often suffers from structural inconsistencies under complex geometric transformations. Existing learning-based methods generally face a trade-off between the limited global context of CNNs and the high computational cost of Transformers. In addition, current training protocols, largely dominated by simple linear motion, fail to capture the geometric and imaging complexities encountered in real-world videos. To address these issues, we propose GeoMag, a geometric-aware VMM framework built upon State Space Models to achieve globally consistent motion amplification with linear complexity. We further construct Geo-200K, a large-scale synthetic dataset that introduces rich geometric transformations together with sensor-realistic degradations, improving the diversity and realism of training signals. Extensive experiments on synthetic and real-world benchmarks show that GeoMag consistently outperforms prior methods in visual fidelity and computational efficiency, while producing fewer artifacts and better structural consistency.
Kecheng Han, Yuchen Zhang, Bingqing Liu +3
School of Software Engineering, Xi’an Jiaotong University · 2Xi’an Jiaotong University
Uniform frame sampling can miss brief evidence in sparse-event videos when the VLM sees only K frames. We propose EARS (Evidence-Aware Retrieval via Sound and motion), a training-free, query-free front-end that ranks frames using optical-flow motion and audio energy, then applies temporal non-maximum suppression for diversity. The evidence score alone has frame-level AP 0.39; used only to select frames for the VLM, EARS with temporal diversity reaches localization AP 0.94, compared with 0.88 under Uniform sampling. In the updated matched study, at K = 1 EARS reaches XD-subset F1 0.660 versus 0.614 for centered Uniform (the paired interval includes zero); earlier backbone studies use separate protocols. On mostly-silent UCF-Crime, however, EARS slightly trails Uniform. A single configuration is used across both benchmarks; the new controls do not repeat the original held-out search. EARS therefore targets low-budget videos whose salient evidence aligns with motion or audio; on dense narratives or stealthy events, uniform or semantic selection remains preferable, and cheap modality statistics cannot reliably route between them. Code: https://github.com/mikeslin-ir/EARS
Motion blur arises from the temporal integration of a continuous sharp signal over a finite exposure window, yet existing learning-based methods sidestep this physical model and predict only the sharp signal itself: most single-image deblurring methods recover a single frame at the exposure center, while blur-to-video methods predict a fixed set of frames. We introduce PickMoment, a continuous-time reformulation that directly learns the interval-mean blur over arbitrary sub-intervals of the exposure with a single deterministic model. Drawing an analogy to MeanFlow's average-velocity formulation, we train the model with three supervisions derived from the blur integral: an empirical reconstruction loss from available subframes, an additivity loss that enforces self-consistency across overlapping sub-intervals, and a sharp-frame loss anchored at the zero-interval limit. A single trained model unifies single-image deblurring, blur-to-video generation, and continuous-time pick-a-moment recovery as different queries to the same network, with no separate training for each task. Our PickMoment achieves state-of-the-art performance among generative-based deblurring methods on GoPro and HIDE while competitive against restoration-based methods on RealBlur, and the highest per-frame fidelity on GoPro-7 blur-to-video, all in a single forward pass without iterative sampling.
Junseong Shin, Hyeonsu Jo, Daehyun Kim +1
Department of Artificial Intelligence, Hanyang University · Department of Intelligence Convergence, Hanyang University · Department of Computer Science, Hanyang University