Please describe the actual system.

A scaffold stands in front of the subject, encircling her. This scaffold is fitted with 20 digital SLR cameras and 41 lighting devices. Since we particularly wanted the cameras to be equidistant from the subject, the apparatus is hemispherical. No camera on the system is below the eye level of the person being photographed. Although cameras could be positioned below eye level, we thought that people have a strong psychological resistance to being photographed from below. Even so, there are lighting devices positioned below eye level.

One novel idea at the design stage was to build a special booth in which all the cameras and light sources would be shrouded. The plan was that the subject would enter the booth and be photographed. Although it would have been easier to design the camera set-up that way, it is probably psychologically easier for the subject if the cameras and light sources are visible to a certain extent. It is disconcerting to know that you are being photographed without being able to see any of the equipment. There are also problems relating to personal information and image rights. When you photograph ordinary people, you must make clear the kind of photograph that you are taking and what you will use it for. Thus, we constructed the system in this manner, in the belief that having everything out in the open gives people a sense of security.

Since there have been considerable advances in digital image processing, there was no question that digital photography would be employed. As regards data resolution, high-resolution data makes processing demanding, due to its high volume. However, reducing image resolution would be problematic when viewing part of the data afterwards. When evaluating cosmetics, we can only get a picture of a woman's skin at the time it is being photographed. If there is a break between photographs, the condition of the skin changes—the condition of the skin may even change within a single shoot. A standard macro lens is used. After trying lenses of several different focal lengths and checking the results, we finally selected the Micro Nikkor lens.

How did you calculate the number of cameras that would be used?

As we wanted to photograph a person's face, we thought that a lateral angle of 180 degrees would be just right. For angular analysis, a 90-degree optical angle is often divided into two (at the 45-degree point) and into three (at the 30-degree and 60-degree points). For this reason, 15-degree units (which are applicable to both systems) are often considered. The lens that we are using can properly achieve the desired precision (the ability to photograph a pore) at a range of approximately 1.5 m. Having thus decided on a 3-m-diameter semi-circular configuration, we decided that it was appropriate to space out the light sources and cameras at 15-degree intervals.

Thus, 13 cameras are lined up at face level. There are also three cameras spaced at 15-degree intervals above eye level, facing the subject (these are fewer in number since the subject's hair will somewhat conceal her face when viewed from front above). A further four cameras are positioned diagonally above the subject, two to the right and two to the left, also spaced at 15-degree intervals. Thus, the subject is photographed by a total of 20 cameras. There is also one more camera, located behind the main apparatus to simultaneously record the photographic conditions when the subject is photographed. All 21 cameras can be operated from a computer via a network of USB cables and hubs.

One reason for selecting an SLR camera was that it features the required precision, as mentioned earlier. A second reason is that it is easy to change the lens, so that if some of the cameras are switched to a lens with a long focal length, it is possible to take both ordinary multi-angle images and enlarged full-face photographs in a single photographic shoot, and thus avoid overtaxing the subject. By opting for SLR cameras, we can retain the freedom in future to carry out zoom photography if need be, or to photograph the entire body, if the opportunity arises.

This was also a major factor in our selection of Nikon products. In view of the importance of changing lenses, we needed to pick a reliable camera manufacturer with a comprehensive line-up of lens products from whom we can expect consistent support in the future.

Schematic diagram for multi-angle image capturing system

Serial shooting while modifying illumination conditions is possible.

The architecture of the multi-angle image capturing system

The system connects 21 cameras via USB cables and nine USB hubs, and can be controlled using software on a PC. After the photographs are taken, the data stored on the cameras is automatically transmitted to the server in sequence, and displayed on three monitors (one for the photography log, one for the listing of multi-angle images, and one for the image from the optional camera).