While Arri isn’t the first camera company to come to mind for most of us, it’s one of the oldest and most successful. For nearly a century, it has been the leading provider of movie cameras to the feature film industry. For most of that time it has sold film cameras, but its digital Alexa camera has dominated the Oscars for Best Cinematography since its introduction nearly a decade ago. Looking for diversification, the company is hoping to break in to the lucrative surgical microscope market with its Arriscope, which is built around the Alexa sensor.
Surgical microscopes are way more than just microscopes
The core functionality of a surgical microscope isn’t that different from the ones we all peered through in science class. The surgeon looks through a binocular eye piece that provides a magnified view of the operation they are performing. For obvious reasons, it’s important the optics are of the highest quality. But that’s just the beginning of what make the business of building surgical microscopes difficult. The first challenge is providing a view of the surgery on one or more displays, for the rest of the surgical team in the operating room. That means a camera that either needs to siphon off some of the light from the optical path, or that sits alongside the eyepiece. If the camera is separate from the eyepiece, its view won’t be accurately aligned with that of the surgeon.
Arriscope: A fully-digital surgical microscope
Arri is addressing these needs by using its award-winning Alexa sensor as the heart of an all-digital solution. The Alexa sensor is widely celebrated for its industry-leading dynamic range and low noise. In the Arriscope, binocular optics are replaced by micro LCDs (much like the EVFs of a mirrorless camera), and the same sensor can drive both those displays and larger displays for use in the OR. The same video can even be piped to classrooms or used later for education. Arri started by approaching makers of existing surgical microscopes on a potential partnership, but when none of them were interested, it decided to create its own product.
After the initial mechanical, optical, and digital system was designed, Arri then needed to address the unique color matching issues associated with highly accurate rendering of living human tissue. Hans Kiening, General Manager of Arri’s Medical subsidiary, explained to us that blood was particularly tricky. Initially the prototype scopes were tested using cadavers, but that didn’t provide a good-enough test bed for use in actual surgeries. So they needed to use the prototype as a research tool in surgery to finish tuning their color calibration software.
Ensuring low latency is another challenge when replacing a real-time optical system with a digital image pipeline. Arri is aiming to get its latency below 30ms, but surgeons so far are working successfully with its current 40ms to 50ms lag.
One important note about this type of external scope is that it is very different from the tiny endoscopes that need to operate inside the patient. Those scopes have to operate with extra-small lenses and short working distances. So they can’t use the same technology that the Arriscope uses. As a result, the Arriscope is aimed at externally-directed operations — initially certain types of Ear, Nose, and Throat (ENT) operations. It’s already in use at several clinics in Arri’s native Germany, and has been used in over 100 operations. The company’s next step is to expand into the US market, once it receives needed FDA approvals.
Here, 3D really matters
Since the surgeon is using the view through the microscope to guide their hands, the view not only needs to be high quality, but it has to be 3D. Arri has taken a unique approach to doing this, capturing both left and right views on a single Alexa sensor, through a clever manipulation of the optical path.
Ironically, it was Hollywood’s failed love affair with 3D film making that helped propel Arri into digital. After the success of Avatar 3D, demand for digital 3D cameras for use on feature films skyrocketed, while sales of traditional film models plunged. That drove a rapid innovation cycle at Arri, and resulted in the Alexa sensor. By the time the movie industry realized 3D wasn’t going to be “the next big thing” the shift to digital was a fait accompli. Now, while some film makers still use analog cameras, new sales of film cameras for the movie industry are almost non-existent.
Hands-on with the Arriscope
The Arri team brought an Arriscope to Stanford, where I was able to use it (on the mock up of an ear). The quality of the image through the eyepieces was far beyond anything I’ve seen in a commercial EVF, and it’s truly 3D — with each eye receiving its own view from the appropriate perspective. The scope couples its 6MP sensor with a 3x optical zoom. At this point it doesn’t incorporate a digital zoom, although Arri executives told us it might in future versions as they increase the sensor’s native resolution.
Impressively, the calibrated 3D LCD that is also attached to the scope showed essentially the identical image (when used with cheap 3D glasses). So everyone in the OR can see exactly what the surgeon is seeing. The scope’s mechanical design makes it easy to move the eyepiece around, although the overall unit is far from portable — it arrived at Stanford in a 1,000-pound crate.
Going beyond the visible
Perhaps the largest advantage of a purely digital system is the ability to enhance the surgeon’s view. For example, cancerous tissues can be painted in false color, based on image analysis that can identify particular types of tissue by their reflectivity. This way, a surgeon would know when they had removed an entire tumor, reducing the risk that any cells are left behind to cause a remission. Another capability is accurate measurements. For example, the system can provide interior ear measurements to allow selecting the proper size implant without trial and error.
There is no doubt in my mind that digital microscopes will be the future for surgery. For now, it seems like Arri is out in front of the rest of the industry. But don’t be surprised if we start to hear from other high-end camera companies like RED, or traditional microscopy vendors like Nikon and Olympus.