Hyperfocal distance

Abstract: Light field rendering has been proposed to render novel images from a collection of captured images without explicit geometry information. In this report, we present an optical analysis of light field rendering. In particular, a light field rendering system can be considered as a virtual imaging system with a discrete synthetic aperture (e.g., [10]. We define the key elements of the virtual imaging system including the aperture, the circle of confusion, the depth of field, the hyperfocal distance and the imaging law of the constant depth rendering, with analogy to a conventional optical imaging system. Based on the optical analysis of the virtual imaging system, we describe the relationship among the depth variation of the scene (depth of field), the constant depth(perfectly focused plane), the spacing of cameras (aperture) and the rendering resolution (circle of confusion). Specifically, the hyperfocal distance of the virtual optical system, as a key parameter for light field rendering, determines the relationship between the spacing of cameras and rendering resolution. Given the minimum and maximum depths of the scene, the optimal constant depth and the hyperfocal distance are derived to achieve the best rendering quality or minimum number of images. The minimum number of images required for anti-aliasing rendering (i.e., the rendering error is smaller than the circle of confusion) can be further reduced by segmenting the depth into multiple depth layers. A quantitative relationship between hyperfocal distance, number of layers, and depth variation of the scene is described.

Abstract: The invention provides a mobile terminal picture shooting method and system. The method includes responding to a shooting command, determining the closest focusing distance and the hyperfocal distance of shot scenery, increasing the focusing distance with the preset focusing distance increment as a shooting interval from the closest focusing distance of the shot scenery to the hyperfocal distance, shooting pictures with different focuses of identical scenery and then pushing and displaying the pictures obtained through shooting. At the moment, a user can directly check pictures with different focuses of the identical scenery on a mobile terminal, and the user can select the picture with a proper focus according to self interest. The mobile terminal picture shooting method is simple, enables the user to select the picture with the proper focus freely, meets difference requirements of the user and brings good use experience.

Abstract: PROBLEM TO BE SOLVED: To shorten a photographing time lag and obtain a focused image in a wide distance range in a multi-viewpoint imaging apparatus SOLUTION: Respective focus positions of focus lenses in a plurality of imaging optical systems to which two or more pieces of identification information n (n=1, 2, 3) that do not overlap each other are given are set to lens positions corresponding to a subject distance L of H/(2n-1) or more (H is hyperfocal distance) By performing simultaneous imaging in which subject images with received light of respective imaging optical systems are simultaneously converted into image data by corresponding imaging devices according to imaging instructions, the focused image is obtained in the wider distance range in proportion to the number of the imaging optical systems COPYRIGHT: (C)2010,JPO&INPIT

Abstract: The resolution performance of mobile phone camera optics was previously checked only near an infinite point. However, near-field performance is required because of reduced camera pixel sizes. Traditional optics are measured using a resolution chart located at a hyperfocal distance, which can only measure the resolution at a specific distance but not at close distances. We designed a new collimator system that can change the virtual image of the resolution chart from infinity to a short distance. Hence, some lenses inside the collimator systems must be moved. Currently, if the focusing lens is moved, chromatic aberration and field curvature occur. Additional lenses are required to correct this problem. However, the added lens must not change the characteristics of the proposed collimator. Therefore, an equivalent-lens conversion method was designed to maintain the first-order and Seidel aberrations. The collimator system proposed in this study does not move or change the resolution chart.