Capture the moment

The recently redesigned and reopened Museum of Modern Art in New York City is a greatly expanded and fascinating place to see all sorts of art dating from the mid-19th Century to today.

Feb 1st, 2005

The recently redesigned and reopened Museum of ­Modern Art in New York City is a greatly expanded and fascinating place to see all sorts of art dating from the mid-19th Century to today. One of the advantages of the redesign is expanded space for photography, especially of images dating back to its early days. You can see the startling images by Eugène Atget (1857-1927) of the streets and parks of Paris, frozen in time, devoid of any implication of movement. French Impressionist artists would commission him for photographic studies from which they would paint.

Then there are the photographs by Etienne-Jules ­Marey (1830-1904), a Frenchman who loved physics, ­engineering, and the human body in motion. Marey’s photo of a man running captures six successive strides as the figure seems to hurtle across a single image. It was inspired by the work of Eadweard Muybridge (1830-1904), an English-born American who used a battery of cameras in taking a sequence of separate frames to capture motion, most famously of a galloping horse. In contrast, Marey recorded the successive phases of motion on a single plate, providing an image that at once analyzes motion and presents a virtual image of its course.

Those very still pictures of Paris by Atget were printed on paper impregnated with whipped and salted egg white, which he had soaked in a bath of silver nitrate before putting in a printing frame with a glass negative and exposing it to sunlight until an image appeared, then fixing and toning it with a gold salt. The resulting images are exceptionally sharp and detailed. Muybridge developed a novel timing mechanism and an electromagnetic latch to release the shutters on his batteries of 12 cameras. And Marey went on to develop the “chronophotograph,” from which the motion picture camera was developed. One of Marey’s cameras could capture images at a rate of 700 per second.

No time like the present

This excursion into the history of photography simply reinforces to me how modern scientific and industrial digital imaging is part of a continuum well-explored within the limits of technology for more than 160 years. The search to capture motion has continued to today’s high-speed ­digital ­cameras that can freeze time in an image at upward of 100,000 frames/s, depending on the number of pixels used. It seems a ridiculously fast rate, but very useful for some military, R&D, and industrial applications.

Until recently, the lack of standard off-the-shelf components meant that high-speed camera makers had to offer fully integrated, proprietary systems that were limited in terms of ­image-capture speed, length of image sequences captured, and image-processing capability. The use of standard interfaces such as Camera Link, FireWire, and USB, and improvements in off-the-shelf components such as frame grabbers, DSPs, software, and CMOS imaging sensors have broadened the number of high-speed products available and lowered costs considerably. The increase in on-board or interfaced memory means that these new high-speed camera systems feature extended recording times, which is critical for many testing applications.

The list of proven and potential industrial uses for high-speed imaging keeps growing, and includes particle-­image-velocimetry applications such as fuel-spray ­analysis, ­production-line diagnostics, and mechanical component testing. A novel high-speed camera from Analogic Computers (Budapest, Hungary) that I wrote about over a year ago is now part of manufacturing systems deployed by Jakob Müller (Schwelm, Germany) to produce and inspect woven clothing labels (see Laser Focus World, January 2004, p. 62). Other relative newcomers such as Fastec Imaging (San Diego, CA) and Photonfocus (Lachen, Switzerland) join established high-speed camera makers such as Basler ­Vision Components (Ahrensburg, Germany), Dalsa (Waterloo, Canada), PCO ( Kelheim, Germany), Photron (San Diego, CA), and Redlake (San Diego, CA) in what is becoming an increasingly competitive and varied market.

Using new processes and technologies, these specialized high-speed cameras have continued what Atget, Marey, and Muybridge had begun. As French critic and ­novelist Alphonse Karr (1808-1890) wrote just about the time the first photographic images were being taken, “The more things change, the more they remain the same.” But he said it in French, of course.

CONARD HOLTONis editor in chief of Vision Systems Design; e-mail: cholton@pennwell.com.

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