This paper presents a comprehensive pipeline for recognizing objects targeted by human pointing gestures using RGB images. As human-robot interaction moves toward more intuitive interfaces, the ability to identify targets of non-verbal communication becomes crucial. Our proposed system integrates several existing state-of-the-art methods, including object detection, body pose estimation, monocular depth estimation, and vision-language models. We evaluate the impact of 3D spatial information reconstructed from a single image and the utility of image captioning models in correcting classification errors. Experimental results on a custom dataset show that incorporating depth information significantly improves target identification, especially in complex scenes with overlapping objects. The modularity of the approach allows for deployment in environments where specialized depth sensors are unavailable.
Figures & tables
Fig. 1: The full pipeline of the proposed system. The input image (a) is fed into three parallel branches: pose estimation (b), object detection (c) and depth estimation (d). The outputs of the three branches get combined to first classify whether pointing occurs and which detected object is pointed at (e). Finally, an image captioning module (f) is used to provide a better description of the object and to potentially fix an incorrect object label assignment.
Fig. 2: Sample images from our dataset. We use different types of gestures to indicate pointing at objects and neutral poses (no pointing). The dataset captures different levels of complexity in terms of item positions.
Case
MoGe
Features
Precision
Recall
F1
Accuracy
Easy
✓
kpOnly
0.53
0.86
0.66
0.77
Easy
✓
full
0.56
0.91
0.69
0.80
Hard
✓
kpOnly
0.48
0.83
0.61
0.71
Hard
✓
full
0.47
0.80
0.59
0.70
Easy
×
kpOnly
0.50
0.70
0.59
0.67
Easy
×
full
0.56
0.67
0.61
0.72
TABLE I: The classification accuracy results for determining whether pointing occurs in an image (see Sec. III-E ). The results shown are for combination with YOLO11s [ 2 ] with ( ✓ ) and without ( × ) MoGe depth estimation [ 5 ] .
Easy Cases
Model
MoGe
Precision
Recall
F1
Accuracy
YOLOv8s
×
0.42
0.49
0.45
0.63
✓
0.49
0.67
0.56
0.74
YOLOv8n
×
0.54
0.44
0.49
0.70
✓
0.51
0.62
0.56
0.74
YOLO11n
×
0.46
0.39
0.43
0.65
TABLE II: Comparison of object recognition performance across various detection models with ( ✓ ) and without ( × ) MoGe depth estimation [ 5 ] . Results are categorized into Easy Cases (horizontal separation) and Hard Cases (depth-wise overlap).
Case
Captioning
Precision
Recall
F1
Accuracy
Easy
×
0.56
0.91
0.69
0.80
BLIP
0.58
0.92
0.71
0.81
ViT-GPT2
0.56
0.91
0.69
0.80
GIT
0.58
0.92
0.71
0.81
Hard
×
0.47
0.80
0.59
0.70
BLIP
0.51
0.81
0.62
0.71
TABLE III: Pointed-at object recognition results for YOLO11s [ 2 ] object detector combined with different image captioning methods used for correcting badly classified objects (see Sec. III-F ).
Tsinghua University Beijing Shi, China · Beijing University of Posts and Telecommunications Beijing Shi, China · Tsinghua Shenzhen International Graduate School Shenzhen, Guangdong, China +1