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Calibration targets for use with digital cameras comprise black
and white target areas to which digital cameras are exposed simultaneously
to provide proper settings for highlight and shadow sensitivity
prior to making a digital photograph. In addition a white or gray
neutral target area, without color bias, is provided, to which the
digital cameras are exposed to provide desired settings for color
balance prior to making digital photographs. In one embodiment of
the calibration target, the black and white target areas are on
one side of a panel and the white or gray neutral target area is
on the other side of the panel. In accordance with methods of calibrating
digital cameras and to methods of photography, the image of the
black and white target areas is adjusted by viewing a histogram
display thereof and adjusting exposure settings until spikes in
the histogram representing black and white detection are equally
balanced between boundaries with no lateral offset.
An apparatus and method for detecting and correcting for physical
misalignments of a pair of digital cameras creating a composite,
three dimensional (3D) image of a target. The method involves using
the distances from each of a pair of digital cameras to a target
and determining correction offset values for one or the other of
the images produced in the digital cameras to achieve pixel-to-pixel
coincidence of the two images. The correction offset values are
calculated and performed in real time and eliminate the need to
physically remove a common platform on which the cameras are mounted
from a mobile platform or other support structure, and to transport
same to a laboratory environment for the needed calibration. Advantageously,
the correction values are generated electronically and applied in
real time as any misalignment between the cameras is sensed.
A multifocal lens system to be used for digital cameras for setting
any one of a plurality of lenses in a picture taking (image capturing)
position comprising a wide-angle lens (shorter focal length lens)
mounted in front of an image sensor in a picture taking (image capturing)
position, a telephoto lens (longer focal length lens) mounted alongside
the wide-angle lens, a parallelogram prism (rhombic prism) or a
pair of triangular prisms removably arranged between the two lenses
at the rear of them. When the wide-angle lens is to be used, the
parallelogram prism or one of the two triangular prisms is to be
removed from the rear of wide-angle lens so that the wide-angle
lens can be focused on the sensor enabling light to pass therethrough.
The telephoto lens is so positioned that it may be focused on the
image sensor through the parallelogram prism or being reflected
by the triangular prisms enabling light to pass therethrough when
a part of the parallelogram prism or one of the two triangular prisms
is placed in front of the image sensor to cover the imaging area
of the sensor and to shut the light through the wide-angle lens
to the sensor. By moving the prism from the rear of each lens, one
of the two lenses can be positioned for picture taking (image capturing).
A system of linked digital cameras for an image capture system
is disclosed. A first and second digital camera can be linked to
capture a first images and a second image that are used to form
a stereo image. A first data port on the first digital camera and
a second data port on the second digital camera intercommunicate
data between each other when the cameras are linked. The data can
include the first and second image data, camera control data, and
camera synchronization data. After capturing the first and second
images, the image from one of the cameras can be transferred to
the other camera so that both the first and second images reside
in the other camera. The system allows a user who wishes to capture
stereo images the ability to do so with out having to purchase two
digital cameras. A compatible digital camera can be borrowed from
another user for the purpose of stereo image capture. After the
stereo image is captured, the user transfers both images to his
camera and returns the borrowed camera. The cameras can be equipped
with viewfinders that allow a user of the cameras to view the image
being captured in stereo. The viewfinders can be adjustable to accommodate
variations in user interpupillary distance. A digital camera operating
system (OS) can be customized to enable stereo image capture, image
data handling, image processing, and camera control for the linked
digital cameras.
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