Once you have decided how many photographs you will take and where you will take them from, you can go to your object or your site and take the photographs. Special care should be taken to ensure good exposure and good focus.
Note: The photography requirements for a SmartPoints project are different than those for a regular PhotoModeler project. See DSM Photo Requirements and SmartPoints Photo Requirements for more information on photography for SmartMatch projects.
It is a good idea to take more photographs than you strictly need for the Measurement Project. Some of the photographs may have bad exposure or bad focus, or perhaps later you may wish to measure more points than originally planned.
Note: When taking photographs, you should also measure the distance between at least two points on the object. This distance will be used to add scale to your end-product, the 3D model. Additional measured distances can be used to check the accuracy of the result.
This section deals mostly with multiple-photograph projects. The requirements for single photograph control-based projects are not as strict and are described at the end of this section.
For best results some guidelines should be followed when positioning the camera during photography. The following is a summary of some guidelines for how photographs should be taken. These guidelines are each discussed in detail in this chapter.
Photography guidelines:
• try to get the angles between the shots as close to right angles (90 degrees) as possible,
• take at least three photographs but it is a good idea taking more than you think you’ll need to avoid having to return to the site to take more,
• try to get all important points on at least three photographs,
• try to get as much overlap between adjacent photographs as possible,
• try to get photographs from both above and below the object, if possible,
• take many photographs of the object but use at most four at the start until you determine you need others, and accurately measure the distance between two clearly visible points in the scene for later use as scale in your project.
While these guidelines refer mostly to multiple photo point-based projects they apply to shape-based projects too. They do not apply that much to single photo projects but there is a sub-section below addressing that topic.