A data set of 173 cases was collected for this study: 81 cases in the training set (42 lesions, 21 wall thickenings, 18 normal bladders) and 92 cases in the test set (43 lesions, 36 wall thickenings, 13 normal bladders). EDWP uses changes in energies, smoothness criteria of the contour, and previous slice contour to determine when to stop the propagation, following decision rules derived from training. EDWP with regularized energies further propagates the conjoint contours to the correct bladder boundary. MGR propagates the C region contours if the level set propagation in the C region stops prematurely due to substantial non-uniformity of the contrast. To alleviate this problem, we implemented a local contour refinement (LCR) method that exploits model-guided refinement (MGR) and energy-driven wavefront propagation (EDWP). In case the bladder is partially filled with contrast, CLASS segments the non-contrast (NC) region and the contrast-filled (C) region separately and automatically conjoins the NC and C region contours however, inaccuracies in the NC and C region contours may cause the conjoint contour to exclude portions of the bladder. Previously, we proposed a Conjoint Level set Analysis and Segmentation System (CLASS). Fish and Wildlife Service Home Page |Ībout the U.S.The presence of regions filled with intravenous contrast and without contrast presents a challenge for bladder segmentation. The Feather Atlas illustrates feathers in ventral view only when the under surface is very different from the upper surface (e.g., in Black and Turkey Vultures). Ventral: the under surface of the body, or of any body part oriented in a normal horizontal postion. The posterior vane is the trailing edge of the feather. On remiges, the anterior vane is on the forward side of the rachis (the leading edge). Vane: the smooth feather surface formed by the interlocked pennaceous barbs. Tertial: the innermost flight flight feathers of the wing, attached to the humerus bone in the bird's upper arm. If obvious, usually indicates that a feather is from waterfowl. Tegmen: a shiny or waxy-looking patch along the shaft on the underside of primaries of waterfowl and some gamebirds, gulls, and owl. In such species, age is often estimated by plumage stage (e.g., Subadult I, II, and III for Bald Eagles). Subadult: a bird that is not fully adult, in species that require more than one year to achieve adult plumage (e.g. Secondary: one of the wing's inner flight feathers, which are attached to the ulna bone in the bird's "forearm." The number of secondaries varies from 9-25 depending on the species. ![]() Rectrices: the flight feathers of the tail. Remiges: the flight feathers of the wing, including the primaries, secondaries, and tertials. Rachis: the upper portion of the feather shaft, to which the barbs are attached. Primary: one of the wing's outer flight feathers, which are attached to the fused bones of the bird's "hand." Most bird species have 9-10 primaries. Plumulaceous Barbs: barbs without interlocking barbules, forming a loose fluffy layer at the base of a contour feather or making up the entirety of a down feather. Pennaceous Barbs: barbs with interlocking barbules that form a coherent vane. Notch: a distinct narrowing in the posterior vane of a primary flight feather. Immature: a young bird in its first year, before it has acquired adult plumage. Most scans in the Feather Atlas illustrate the feathers in dorsal view, showing the upper surface of the feathers.Įmargination: a distinct narrowing in the anterior vane of a primary flight feather.įlight Feathers: the large wing and tail feathers that provide lift and maneuverability in flight (see "Remiges" and "Rectrices"). ![]() In some birds, such as eagles, these are large enough to merit illustration in the Feather Atlas.ĭorsal: the upper surface of the body, or of any body part oriented in a normal horizontal position. Those on the upper (dorsal) surface of the body are called upper wing and upper tail coverts those on the under (ventral) surface are called under wing and under tail coverts. Sometimes called the quill.Ĭontour Feathers: the feathers forming the bird's outer body covering, including the flight feathers and the overlapping body feathers that produce the bird's smooth aerodynamic shape.Ĭoverts: the contour feathers that cover the bases of the flight feathers. ![]() In some birds, such as Bald Eagle, these are large enough to merit illustration in the Feather Atlas.īarb: an individual strand of feather material (keratin), extending laterally from the rachis.īarbule: a lateral branch of a feather barb.Ĭalamus: the hollow inner portion of the feather shaft that lacks barbs and attaches to the skin. Axillaries: feathers in the axilla ("armpit") of the bird.
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