Photogrammetry In Filmmaking

What is Photogrammetry?

Photogrammetry is the science of making measurements from photographs.

The output of photogrammetry is typically a map, drawing or a 3d model of some real-world object or scene. Many of the maps we use today are created with photogrammetry and photographs taken from aircraft.

Digital photogrammetry is an art which is used to obtain the measurements of objects in a photograph by using computers.It typically involves analyzing one or more photographs with photogrammetry software to determine spatial relationship.

It is useful for a photogrammetrist to know information about the camera, such as what type of camera took the photograph, the focal length of the lens, or the distance of the camera to the object of interest. A special type of camera, called a metric camera, is used to take these photographs because it is calibrated to take precision photographs with little lens distortion.

A second variable to consider in digital photogrammetry is the desired dimensions of the measurements. Some projects require only two dimensional (2D) measurements, such as the height of a building or the width of a river. These measurements can be made from a single photograph but if the measurements need to be three dimensional (3D), the process will then involve creating a 3D model from two or more photographs.This process of creating a 3D model is usually called digital stereophotogrammetry.

Digital Stereophotogrammetry

Stereophotogrammetrists usually analyze two or more photographs of the same object, taken from different angles. They typically use the space where the photographs overlap or common points of reference shared by the photographs to create a digital 3D model. The images may then be mapped, pixels by pixel within the model to create measurable space in three dimensions.

Types of Photogrammetry

A Google map 3d building created using Photogrammetry

Photogrammetry can be classified a number of ways but one standard method is to split the field based on camera location during photography. On this basis we have Aerial Photogrammetry, and Close-Range Photogrammetry.

Aerial digital photogrammetry

Aerial digital photogrammetry, often used in topographical mapping, begins with digital photographs or video taken from a camera mounted on the bottom of an airplane. The plane often flies over the area in a meandering flight path so it can take overlapping photographs or video of the entire area to get complete coverage.

Close-range digital photogrammetry

Close-range, or terrestrial, digital photogrammetry often uses photographs taken from close proximity by hand held cameras or those mounted to a tripod. Close-range photographs can be used to create 3D models, but they are not usually used in topographical mapping.This type of photogrammetry is useful for the 3D modeling of many objects or areas such as buildings,automobile,movie sets or even characters.Photogrammetry is a great tool for filmmakers to recreate real world sets and characters exactly the way they are in real.

The use of this technique can be seen in the film "The Matrix",the movie which gave new heights to vissual effects in films.

Here's a video where Leah D'Emilio learns about a whole new approach to visual effects in film from Dr. Paul Debevec, innovator of HDR photography and creator of Photogrammetry takes us through USC's Institute for Creative Technologies.Enjoy ☺

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