Digital camera

About: Digital camera is a research topic. Over the lifetime, 12169 publications have been published within this topic receiving 137431 citations. The topic is also known as: digicam & digital still camera.

Digital camera self-calibration

Abstract: Over the 25 years since the introduction of analytical camera self-calibration there has been a revolution in close-range photogrammetric image acquisition systems. High-resolution, large-area ‘digital’ CCD sensors have all but replaced film cameras. Throughout the period of this transition, self-calibration models have remained essentially unchanged. This paper reviews the application of analytical self-calibration to digital cameras. Computer vision perspectives are touched upon, the quality of self-calibration is discussed, and an overview is given of each of the four main sources of departures from collinearity in CCD cameras. Practical issues are also addressed and experimental results are used to highlight important characteristics of digital camera self-calibration.

Digital camera calibration methods: Considerations and comparisons

Abstract: Camera calibration has always been an essential component of photogrammetric measurement, with self-calibration nowadays being an integral and routinely applied operation within photogrammetric triangulation, especially in high-accuracy close-range measurement. With the very rapid growth in adoption of off-the-shelf digital cameras for a host of new 3D measurement applications, however, there are many situations where the geometry of the image network will not support robust recovery of camera parameters via on-the-job calibration. For this reason, stand-alone camera calibration has again emerged as an important issue in close-range photogrammetry, and it also remains a topic of research interest in computer vision. This paper overviews the current approaches adopted for camera calibration in close-range photogrammetry and computer vision, and discusses operational aspects for self-calibration. Also, the results of camera calibrations using different algorithms are summarized. Finally, the impact of chromatic aberration on modelled radial distortion is touched upon to highlight the fact that there are still issues of research interest in the photogrammetric calibration of consumer-grade digital cameras.

Digital light field photography

Abstract: Focusing images well has been difficult since the beginnings of photography in 1839. Three manifestations of the problem are: the chore of having to choose what to focus on before clicking the shutter, the awkward coupling between aperture size and depth of field, and the high optical complexity of lenses required to produce aberration-free images. These problems arise because conventional cameras record only the sum of all light rays striking each pixel on the image plane. This dissertation presents a unified solution to these focus problems by instead recording the light field inside the camera: not just the position but also the direction of light rays striking the image plane. I describe the design, prototyping and performance of a digital camera that records this light field in a single photographic exposure. The basic idea is to use an array of microlenses in front of the photosensor in a regular digital camera. The main price behind this new kind of photography is the sacrifice of some image resolution to collect directional ray information. However, it is possible to smoothly vary the optical configuration from the light field camera back to a conventional camera by reducing the separation between the microlenses and photosensor. This allows a selectable trade-off between image resolution and refocusing power. More importantly, current semiconductor technology is already capable of producing sensors with an order of magnitude more resolution than we need in final images. The extra ray directional information enables unprecedented capabilities after exposure. For example, it is possible to compute final photographs that are refocused at different depths, or that have extended depth of field, by re-sorting the recorded light rays appropriately. Theory predicts, and experiments corroborate, that blur due to incorrect focus can be reduced by a factor approximately equal to the directional resolution of the recorded light rays. Similarly, digital correction of lens aberrations re-sorts aberrant light rays to where they should ideally have converged, improving image contrast and resolution. Future cameras based on these principles will be physically simpler, capture light more quickly, and provide greater flexibility in finishing photographs.