Summary For The Test Sequences
This report summarizes the challenges and complexities faced during motion detection tests using Logitech's Orbit and QuickCam Pro cameras. Key issues such as false detections caused by glare, dust, and environmental factors like wind and precipitation are addressed. The findings highlight the limitations of various detection approaches, including optical flow analysis, background subtraction, and temporal differencing. Each method's advantages and disadvantages are discussed, providing valuable insights for improving moving object detection in diverse conditions.
Summary For The Test Sequences
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Presentation Transcript
Logitech Orbit 10ft Vertical Run 2 Frame 43: False detection due to glare Frame 141: Event of interest
Logitech Orbit 10ft Vertical Run 3 Frame 159: Event of interest Frames 72&170: False detection due to dust
Logitech Orbit 20ft Vertical Run 2 Frame 150: Event of interest
Logitech Orbit 20ft Vertical Run 3 Frame 121: Event of interest
Logitech QuickCamPro 5000 10ft Vertical Run 3 Frame 91: False detections due to dust Frame 150: Event of interest missed due to shadow and insufficient contrast
Logitech QuickCamPro 5000 20ft Vertical Run 2 No event of interest
Logitech QuickCamPro 5000 20ft Vertical Run 3 Frame 104: Event of interest
Challenges & Complexities • Motion versus change detection • Aperture problem for optic flow approaches • Learning appropriate background for change (ghost objects appear due to slow or fast learning) • Global camera motion/jitter • Occlusion and Camouflage • Environmental problems • Precipitation –rain, slow etc. • Wind –local object motion (swaying of branches, shadows) • Clutter (background model) • Dust and smoke • Illumination problems • Shadows (static and moving cast shadow) - missed objects or false detections • Sudden illumination changes (cloud movements) – false detections • Glare – false detections, object shape and trajectory distortions • Low contrast or color saturation
Moving Object Detection Approaches • Optical Flow Analysis: Characteristics of flow (velocity) vectors of moving objects over time are used to detect changed regions. Advantage: can be used in the presence of camera motion. Disadvantage: usually computationally expensive & aperture problem. • Change Detection • Background subtraction: Moving regions are detected through difference between the current frame and a reference background image. | framei-Backgroundi |>Th Advantage: provides the most complete feature data. Disadvantage: sensitive to dynamic scene changes due to lighting and extraneous events and cannot handle global motion. • Temporal differencing: Similar to background subtraction but the estimated background is the previous frame. | framei-framei-1 |>Th Advantage: very adaptive to dynamic environments. Disadvantage: has problems in extraction of all relevant feature pixels (aperture problem).