micro-chips Technology

Let’s take a snapshot of photogrammetry

We’re all always taking photographs. But did you know that they all have 3D potential?

There is something to be said about how deep digital photo-technology has penetrated our daily lives. We feel incomplete the second our phones aren’t at the ready to document yet another inconsequential moment. While digital photography has been used in conservation, architecture, and urban planning for years now, it is continuing to grow phenomenally. Enter photogrammetry (photo = light; gram = drawing; metry = measurement).

Simply put, this is the process of converting a set of plain, old 2D photographs into a virtual 3D model. “We use overlapping images that capture all the details of an object. A software then stitches the data up to generate a light, usable, and incredibly detailed 3D model,” explains Ayaz Basrai, co-founder of Goa-based The Busride Design Studio. These are then used in gaming, movie-set design, 3D printing, and conservation and archival efforts.

Think, for example, of rare sculptures that museums have made accessible to world audiences by uploading a 3D, digital image — you can rotate this image, zoom in and out, and even turn it upside down to get a closer look at its details. You’re able to do this because of photogrammetry.

Beyond prints

“As tech goes, it’s one of the simplest and most versatile,” says Basrai. To start off the process, you’ll take a series of photographs. What is important, regardless of the camera you use, is a ‘good’ photographic sequence. This means, your camera’s aperture ought to remain constant through the entire shoot, while also keeping the ISO low, so as to avoid any digital noise in the resulting images. Next, think of how your eyes function, and take photos from all angles of the object. While doing this, keep your shooting distance to the subject constant. Additionally, make sure you’re not using a zoom lens — a prime lens keeps the focal length consistent.

There is a slew of software now to help with the rest. ReCap Photo, labelled an educational tool, is one of the simplest to use: open the software, input your images, and select the option to create your 3D image. This will render a basic model in under half an hour. Another popular option is the award-winning software PhotoModeler. This one even helped produce a full sequence in the 2012 film, The Impossible. Both of these are good starting points.

Basrai, along with a team of exhibition-design students working on an experimental VR film, had used a combination of phone pictures and drone-footage to generate a 3D model of objects in a stepwell in Gujarat. These were things they couldn’t even see from where they were standing.

Photogrammetry, in its early days, was used to produce topographical maps — you may remember a very stripped-down version of these from your Class X board-exam days. But as VR content grows, and consequently its applicability in multiple fields, Basrai thinks photogrammetry “will soon become one of the many tools to port hyper-realistic real-world experiences into experienced virtual realities”.

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Printable version | Apr 4, 2020 6:23:35 PM | https://www.thehindu.com/sci-tech/technology/microchips-lets-take-a-snapshot-photogrammetry/article26303342.ece

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