Technology for manufacturing 360-degree panoramas
Often I hear the question from people who are interested - and this is done, you need to do to have and to know that? For a long time I resisted, he would not write this article, the network and so plenty of information and actually I myself have received all information from the network and forums. But then I realized that probably would not be fair to send intetesuyuschihsya the vast expanses of the Internet in a free keyword search, make a list of links, it has become a very extensive search for a short time. Was thought to just build a lot of information, combine or skopipastit pieces, but it will not be fair to those people who unknowingly helped me to master the technology.
So what does it take to remove the panorama? First of all desire. The desire to push beyond the visible space, landscape can be very beautiful fragments, but all it is much more beautiful, and the feeling of freedom observer, never had any desire to look beyond the edge of the photo to see something that does not fit into the picture? And our perception is such that we see the world and unconsciously analyze what is on the identity of harmony, even if we take the golden section and build a number of aspect ratio images - all this will have panoramic images. Even vertical panoramas sometimes give not just the ability to see and feel the depth or height. When I first saw the spherical panorama, I experienced a feeling of delight, now we have everything 100% coverage of the space, we are freed from the scope and formats, limiting the visible space, have incredible effects when you can see all the space, unscrew it, compress, deform on request.
Ever since I got the first digital camera, it became clear that the key role played by permission. Raise it I could just folding panoramas, shot with the hands. Hours of melee with the parallax and a bunch of recycled material provided invaluable experience, both in methods of recording and processing of the received material.
Panoramic image can be obtained in two ways, crop the image, cutting off the unnecessary, or adding multiple pictures into one. It is clear that the first method reduces the resolution, but sometimes mediocre picture into a conventional format reprezentabelnuyu panoramic photo. And with the addition of pictures there of some of the optimum number of personnel, it is sometimes quite a pair of shots to get a wonderful panorama.
Below we will focus on the technology of spherical or cubic 3D-panoramas.
Choice of equipment
Panorama can be photographed and a cheap entry level camera, but it is preferable SLR camera with interchangeable lenses - it will give choice and preference in photography. Quality also plays an important role, as a rule professional and semi-professional digital SLR cameras allow you to receive much less noisy frame under the same conditions, and have a much wider range of settings needed for a photographer. Now there is a wide choice of cameras on the market, but the preference is generally used by two well-known manufacturers - Canon and Nikon. Disputes about the preferences and functional advantages of modern timber SLR cameras - is merrymaking sellers, and a separate theme of survival and success in a world where marketers have won engineers. The end result is not so strongly dependent on the crazy price tag or the presence of a dozen allegedly unique features that can achieve excellent results and with the budget, entry-level cameras. Any photographer with a solid veteran has their own preferences, and knows what he wants from the camera, but if you are new, no one interferes with reading forums to gather information or to ask for those who do not color the camera body makes the camera attractive!
One of the most authoritative among the photographers website where you can get comparative information: www.dpreview.com
We will not consider the class of automatic panoramic camera, or specialized units for panoramic photography, such equipment is extremely expensive and designed for special tasks. If there is interest here are a few producers of such complexes: Panoscan, Roundshot
The main criterion for choosing the lens - it's his angle, usually a panorama shot wide-angle lenses. The wider the viewing angle, the smaller the skills necessary for stitching panoramas. Wide-angle lenses are a focal length less than 28mm * 16mm ultra wide-angle less. Lenses can be both a fixed focal length and zumami, with the ability to change focal length within a certain range, which allows the same lens to shoot panoramas with different resolution.
Shaped by the resulting figure by the lenses can be divided into aspherical and spherical. Our eye is arranged in such a way that we see things not as they are formed on the retina, correcting the image occurs in the processing of his brain, but there is a possibility, and optical alignment of the spherical distortion. Aspheric lenses can be universal, they provide a very interesting perspective effect, which allows them to apply not only in everyday life, but the architectural and artistic photography.
Type lenses fisheye, one of the most popular in panoramic photography. Due to the fact that such lenses is covered by an angle of 180 °, number of frames for a panorama greatly reduced, which allows you to receive "fast sphere. " There are two basic types of lenses fisheye: circular fisheye - received frame contains a circle with a viewing angle of ~ 180 ° in either direction (the focal length - 6-8mm, for the crop matrix - 4.5 mm) diagonal fisheye - 180 ° angle of view corresponds to the diagonals of the frame And the image fills the frame (focal length - 14-16mm, for the crop matrix - 8-10,5 mm).
The base lens for panoramic photography: www.vrwave.com
* Matrix of different SLR cameras are not the same physical dimensions, the size of the count is taken, Crop 1 - Full frame 24x36mm, matrix of smaller dimensions: Crop 1.3 - APS-H (Canon); Crop 1.5 - APS-C (Nikon DX, Pentax, Sony) ; Crop 1.6 - APS-C (Canon). This means that the focal length of 24mm, a camera-equipped Nikon DX-matrix will correspond to 16mm.
An important piece of equipment to produce spherical panoramas. Why need a panoramic head and how it differs from a simple tripod head? The thing is that if you try to make a sequence of frames rotating the camera around, let's axis, which coincides with the place of attachment, or an arbitrary axis, you see that the same objects that are closer to the camera move when you turn the relatively remote objects. This phenomenon is called parallax (Greek παραλλάξ, from παραλλαγή, «change, alternation) change in the apparent position of the object relative to background removal, depending on the observer's position. Based on the phenomenon of parallax binocular vision. But if in geodesy and astronomy - the phenomenon used to measure distances to remote objects, the panoramic photo is non interference.
Circumvent the effect of parallax can rotate the camera with the lens around the "point of no parallax" (no-parallax point, NPP). NPP - it's usually a point of convergence of optical axes of the lens and it is located in the center of the entrance pupil of the lens, an imaginary hole in it. Entrance pupil of the lens - the image of the aperture diaphragm, visible through the front of the lens. This visible image can be distorted lens located in front of him, in addition, it is shifted from the place where in fact there is a diaphragm. Just the center of this visible image and a point around which to rotate the camera to avoid parallax. Interestingly, the entrance pupil is also important friend: f-number lens, in fact - is the ratio of focal length to the diameter of the entrance pupil, and not to the physical diameter diaragmy inside the lens. Often, even among professionals, the "point of no parallax," called the "nodal point" - this is not true, but in fact NPP has nothing to do with these nodal points of the lens. These nodal points - it's the other point on the lens axis. You can call the NPP "center prospects," but this term is not universally accepted and does not reflect the importance of the NPP. Some lenses, including those commonly used in panoramic photography lenses Fisheye, have no single point of lack of parallax. Such lenses have a number of so-called "points of the smallest parallax, the position of which depends on the angle to the optical axis of the lens. These lenses are easily recognized by the typical course of the pupil back and forth as the deflection angle from the optical axis when viewed from the lens front. With these lenses, you can choose the optimum angle at which the panorama stitching gives the smallest difference (RMS) and rotate the camera around a point that does not give the parallax at that angle value.
So, what is needed panoramic head, we found out, now let's see what they look like. As a rule - a set of railings, which are connected rotators or held at an angle of conjugation, to ensure rotation of the whole structure around the "point of no parallax. The heads come in to shoot single-row, a simpler design, or multi-row panoramas. Single-row heads consist of horizontal railing (plate), which placed the camera mount that can adjust the location of the camera (to combine the horizontal axis of rotation with the NPP). To capture multi-row panoramas in the design adds an additional vertical and longitudinal rails and angularity rotator that allows you to change the vertical angle of rotation of the camera (provided by rotation around the NPP it only horizontally but also vertically). Despite the simple design principle there are many requirements to parameters of the head, accuracy, stiffness, weight capacity, net weight, the possibility of using non-standard cameras and devices, ease of rotators and retainers, durability and so on.
// To be continued.....