Maximum-likelihood depth-from-defocus for active vision

A new method for actively recovering depth information using image defocus is demonstrated and shown to support active stereo vision depth recovery by providing monocular depth estimates to guide the positioning of cameras for stereo processing. This active depth-from-defocus approach employs a spatial frequency model for image defocus which incorporates the optical transfer function of the image acquisition system and a maximum likelihood estimator to determine the amount of defocus present in a sequence of two or more images taken from the same pose. This defocus estimate is translated into a measurement of depth and associated uncertainty that is used to control the positioning of a variable baseline stereo camera system. This cooperative arrangement significantly reduces the matching uncertainty of the stereo correspondence process and increases the depth resolution obtainable with an active stereo vision platform.

Authors

• William N. Klarquist
• Wilson S. Geisler
• Alan C. Bovik

Keywords

• Focusing
• Lenses
• Layout
• Cameras
• Robot vision systems
• Maximum likelihood estimation
• Stereo vision
• Laboratories
• Machine vision
• Frequency estimation
• Maximum Likelihood
• Transfer Function
• Acquisition System
• Camera System
• Monocular
• Depth Information
• Depth Estimation
• Stereopsis
• Stereo Camera
• Modulation Transfer Function
• Transfer Function Of System
• Maximum Likelihood Method
• Window Size
• Frequency Response
• Image Regions
• Image Plane
• Frequency Components
• Focal Plane
• Focal Length
• Uncertainty Range
• Search Window
• Depth Of Field
• Local Plane
• Vertical Component
• Focal Object
• Scene Images
• Focal Position
• Image Acquisition Process
• Point Source