![]() ![]() The LED flash on the iPhone 5 (top) and 5s (bottom) ![]() IPhone 5s Case, which fits the iPhone 5 just fine. To reduce shadows, use omnidirectional lighting (lighting conditions where light falls on the patterns from all directions.If you’re upgrading from an iPhone 5 to an iPhone 5s, there’s good news: The two phones are identical in size and shape, so most cases for the 5 will fit the 5s, and vice versa. The 'fuzzy' velvet paper available at craft shops also works very well. For example, by gluing black velvet fabric to a white base. To reduce the glare patterns can be made from more non-reflective material. Shadows can be cast across the paper, breaking up white areas in the camera image. Overhead lights may create reflections and glare spots on a paper marker and so make it more difficult to find the marker square. As the markers become more tilted and horizontal, less and less of the center patterns are visible and so the recognition becomes more unreliable.įinally, the tracking results are also affected by lighting conditions. Tracking is also affected by the marker orientation relative to the camera. These markers have a matrix of black and white squares in the interior of the marker, and this barcode can have much lower optical frequency than templates. Replacing the 4.25 inch square pattern used above, with a pattern of the same size but much more complexity, reduced the tracking range from 34 to 15 inches.Īn alternative to using template markers (markers with user-defined tracking patterns in the interior) is available in ARToolKit Professional 2D-barcode markers. low frequency patterns) are the most effective. Patterns with large black and white regions (i.e. In order to increase the usable range, choosing patterns with lower complexity will help. Table 1: Tracking range for different sized patterns. These results were gathered by making maker patterns of a range of different sizes (length on a side), placing them perpendicular to the camera and moving the camera back until the virtual objects on the squares disappeared. Table 1 shows some typical maximum ranges for square markers of different sizes. ![]() The larger the physical pattern the further away the pattern can be detected and so the great volume the user can be tracked in. ![]() There are also range issues in optical tracking, since as marker move further away from the camera, they occupy fewer pixels in the camera display, and there may be insufficient detail for the tracking to correctly identify the pattern. Also, if the marker borders move outside the camera frame, the marker will be clipped at the edge of the camera frame, and having more than 4 corners will fail to be recognised. It also means that if users cover up part of the pattern with their hands or other objects the virtual object will disappear. This may limit the size or movement of the virtual objects. Naturally the virtual objects will only appear when the tracking marks are in view. While vision-based tracking is exciting in enabling so many applications, there are limitations which affect ARToolKit and other vision based systems. ARToolKit is able to perform this camera tracking in real time, ensuring that the virtual objects always appear overlaid on the tracking markers.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |