Abstract: Provided are method and system of calculating cross-section area and included angle of three-dimensional blood vessel branch, comprising: obtaining the contours of a main blood vessel and a branch blood vessel; determining connecting points of the main blood vessel and the branch blood vessel, a three-dimensional branch outer contour, and an initial normal vector of a branch section; determining the position of the branch section at the branch connecting part and an intersecting cross-section of the branch section and the branch outer contour; rotating the three-dimensional branch cross-section contour to obtain an equivalent two-dimensional branch cross-section contour, and calculating the area of the two-dimensional branch cross-section contour; obtaining branch cross-section areas and corresponding normal vectors thereof; and taking the minimum branch cross-section area as the cross-section area of this segment of branch blood vessel, and determining the included angle between the branch blood vessel and t

Abstract: Implementations described herein relate to filtering content items from a set of eligible content items based on a device filter. A mobile application may be incompatible with one or more devices based on an operating system, an operating system version, hardware configurations of the one or more client devices, etc. To remove incompatible content items, a device filter can be generated by comparing a set of required features for the corresponding mobile application with data from a data structure identifying several known mobile devices and associated sets of features. The set of required features for the mobile application may include a minimum operating system version, one or more eligible countries, and/or one or more features of a mobile device. The device filter can include a set of identifiers for the known mobile devices that are incompatible with the mobile application based on the comparison.