Abstract: According to examples, an apparatus may include a processor and a non-transitory computer readable medium on which is stored instructions that may cause the processor to create a 2D reference mesh for an image of a curved visual mark, establish correspondences between finder pattern points in the curved visual mark and points of the 2D reference mesh, and determine a curved 3D mesh having a radius that results in a minimal reprojection error of a projective transform estimated for correspondences between the 2D reference mesh and the curved 3D mesh while the radius remains below a predefined upper limit. The instructions may also cause the processor to sample components of the curved visual mark in elements of the determined curved 3D mesh to form a 2D planar image of the curved visual mark and analyze the 2D planar image of the curved visual mark to read the curved visual mark.

Abstract: In some examples, a mobile device registers an account of a first service with an account control service, the account control service separate from the first service. In response to the mobile device being authorized with respect to the account control service, the mobile device searches for a target device that is within a communication range of the mobile device. The mobile device transmits, to the target device found in the search, a credential of the account of the first service being accessed by the target device over a network.

Abstract: First and second confidence values are determined. The first confidence value corresponds to a likelihood that, from a position and an orientation of a mobile computing device, the mobile computing device is pointing to a visual code. The second confidence value corresponds to a likelihood that, from an image captured by the mobile computing device, the mobile computing device is pointing to the visual code. Whether the mobile computing device is pointing to the visual code is determined based on the first confidence value and the second confidence value.

Abstract: According to examples, an apparatus may include a processor and a non-transitory computer readable medium on which is stored instructions that may cause the processor to create a 2D reference mesh for an image of a curved visual mark, establish correspondences between finder pattern points in the curved visual mark and points of the 2D reference mesh, and determine a curved 3D mesh having a radius that results in a minimal reprojection error of a projective transform estimated for correspondences between the 2D reference mesh and the curved 3D mesh while the radius remains below a predefined upper limit. The instructions may also cause the processor to sample components of the curved visual mark in elements of the determined curved 3D mesh to form a 2D planar image of the curved visual mark and analyze the 2D planar image of the curved visual mark to read the curved visual mark.

Abstract: In one example, a topographic build plate for an additive manufacturing system. The build plate is to support a 3D object fabricated layer-by-layer, and is divided into plural blocks each having a build surface. In-between fabrication of layers of the object, a first one of the blocks is offset in a Z-direction from a second one of the blocks to position the build surfaces of the first and second blocks at different Z-direction locations to replace at least a portion of a support structure of the 3D object.

Abstract: Techniques are described herein for image recognition and retrieval. A system for image recognition and retrieval includes an imager to capture a plurality of image frames. The system also includes an image eliminator to discard any image frame of the plurality of image frames that does not meet a specified quality threshold. A remaining set of image frames is obtained. An image grouper groups the remaining set of image frames into groups of a specified number. A group of image frames is obtained. The system further includes a feature identifier to identify and describe features of the group of image frames. A requester sends a query to a content-based image retrieval server. The query contains descriptors for the features of the group of image frames.

Abstract: Movement of a mobile computing device can be guided so that a current focal distance of a camera of the mobile computing device is within a focal distance range within which other mobile computing devices of a same model type captured images at a same location and in which the visual code was successfully detected. Movement of the mobile computing device can be guided so that a distance between prominent points within an image captured by the camera is within prominent points distance range calculated from a distance between the prominent points within each image captured by the other mobile computing devices. An exposure of the camera can be adjusted to be within a range of exposures at which the other mobile computing devices captured the images.

Abstract: In some examples, a system receives a request for digital content that is responsive to a capture of an image of a mark, receives information relating to a captured image of a user, and in response to the request, identifies, from a plurality of different digital content items associated with the mark, a first digital content item, the first digital content item identified responsive to a characteristic of the user determined based on the captured image of the user, and the plurality of digital content items associated with respective different characteristics of users. The system communicates the identified first digital content item to output, by an output device, information based on the identified first digital content item.

Abstract: In some examples, a mobile device registers an account of a first service with an account control service, the account control service separate from the first service. In response to the mobile device being authorized with respect to the account control service, the mobile device searches for a target device that is within a communication range of the mobile device. The mobile device transmits, to the target device found in the search, a credential of the account of the first service being accessed by the target device over a network.

Abstract: Movement of a mobile computing device can be guided so that a current focal distance of a camera of the mobile computing device is within a focal distance range within which other mobile computing devices of a same model type captured images at a same location and in which the visual code was successfully detected. Movement of the mobile computing device can be guided so that a distance between prominent points within an image captured by the camera is within prominent points distance range calculated from a distance between the prominent points within each image captured by the other mobile computing devices. An exposure of the camera can be adjusted to be within a range of exposures at which the other mobile computing devices captured the images.

Abstract: First and second confidence values are determined. The first confidence value corresponds to a likelihood that, from a position and an orientation of a mobile computing device, the mobile computing device is pointing to a visual code. The second confidence vlue corresponds to a likelihood that, from an image captured by the mobile computing device, the mobile computing device is pointing to the visual code. Whether the mobile computing device is pointing to the visual code is determined based on the first confidence value and the second confidence value.

Abstract: Techniques are described herein for image recognition and retrieval. A system for image recognition and retrieval includes an imager to capture a plurality of image frames. The system also includes an image eliminator to discard any image frame of the plurality of image frames that does not meet a specified quality threshold. A remaining set of image frames is obtained. An image grouper groups the remaining set of image frames into groups of a specified number. A group of image frames is obtained. The system further includes a feature identifier to identify and describe features of the group of image frames. A requester sends a query to a content-based image retrieval server. The query contains descriptors for the features of the group of image frames.