Application and Scalability of Panoramic Cameras is Key
Editor / Provider: a&s International | Updated: 5/9/2012 | Article type: Tech Corner
- Good 360-degree video surveillance is about intelligently integrating the whole process and turning it into a scalable solution.
- People need to start looking at where the market is heading and how 360-degree solutions are going to be incorporated into their business model.
- The market is growing for solutions that require fewer cameras and provide superior image quality.
Panoramic cameras and 360-degree cameras are fairly new to the surveillance party. While the technology is mature, application and user expectation are areas that need to be improved for the newcomers to take foothold in the highly competitive video surveillance market.
The multiple-sensor, composite approach to ultra-wide angle imaging has the advantage of delivering an undistorted panoramic view of the field of interest, said Ellen Cargill, Director of Product Development for Scallop Imaging (a division of Tenebraex). “However, multisensor cameras require sophisticated electronic hardware to synchronize the image sensors, acquire all of the data and put it together into a continuous whole.”
With 360-degree cameras, image processing algorithms and speedy signal processors to remap the data to a rectilinear image, it makes it easier to interpret the image than in its original distorted form. However, this comes at the cost of resolution, as the remapping algorithms tend to fill in nonexistent pixels, Cargill said. “The optical performance of typical fisheye lenses diminishes near the edges of the field, due to sharpness degradation and aberrations such as lateral color.”
Panoramic cameras, which may use multiple lenses and sensors, cost more and are more susceptible to failure due to the added hardware. Another drawback is if the stitching between each view is not seamless, blind spots can occur, said William Ku, Director of Brand Business for Vivotek.
In addition, multiple sensors and lenses require stitching images together that overlap. A single fisheye lens provides one image to see from every angle, using dewarping technology, said Richard Pineau, CTO at Oncam Global. “This is much easier than having to stitch a bunch of images together.”
One imaging challenge for camera manufacturers is illumination. With cameras with fixed focal lenses, the cameras are generally installed so that they point away from direct sources of light or reflective surfaces. For 360-degree cameras, light comes from every direction and saturates, or overexposes, the image if the camera does not have good dynamic range, explained Joel Schaffer, PM of Video Surveillance Applications at Immervision.
In comparison, the lenses in multisensor cameras can have large apertures, thereby delivering great low-light performance, said Ellen Cargill, Director of Product Development for Scallop Imaging (a division of Tenebraex). “Fisheye cameras are constrained to a single exposure for the entire field of view, which may lead to poorly exposed areas within the wide field of view.”
Furthermore, multisensory cameras can employ sophisticated auto-exposure algorithms that allow individual sensors to optimize the exposure, thereby resulting in a properly exposed image over the entire field of view, Cargill continued.
Lighting is a challenge for 360-degree cameras, since the scene may contain both light and dark areas, Ku agreed. “However, well-designed cameras with WDR will perform well even in environments with challenging lighting.” This is less of an issue for controlled environments.
On- or Off-Board Processing
Vendors differ on whether a camera processes the stitching of panoramic images or dewarping of hemispheric images on the camera or via additional software. It depends on what users want and what they are trying to achieve with their video surveillance system.
“We focus on an approach that optimizes the live image with onboard camera software. That way, the user's PC does not experience additional strain as a result of the process, as image correction and generation of the desired images takes place on the camera itself,” said Steve Gorski, GM for the Americas, Mobotix.
Onboard processing combined with a simple recorder is easier on the video surveillance system, as opposed to sending out individual streams that require the use of a powerful computer at the receiving end; it also reduces bandwidth consumption, Cargill said. However, whether processing is done at the edge or in a server is irrelevant to end users, as their key concern is that the system works, Lim said.
“What exactly does the customer want?” said Dallmeier Electronic in a prepared statement. The customer is not particularly concerned with technical specifications, but rather if the goals of their video surveillance system can be achieved effectively.
Good 360-degree video surveillance is about intelligently integrating the whole process and turning it into a scalable solution, said Ahmed Jawad, Chairman of Oncam Global. “That's the big difference. Having it and doing something with it, rather than just having a panoramic or fisheye camera in place for the sake of saying you've got one.”
Over the last five years, advances in processor speed, compression standards and network speeds have improved the performance of the technologies behind panoramic and 360-degree cameras. Functionality in client integration and usability has improved, as has the end-to-end solution. But ultimately it is about what customers do with it that matters, Pineau said.
“The technology is an enabler to allow a process to be deployed — people need to start looking at where the market is heading and how 360-degree solutions are going to be incorporated into their business model,” Jawad said.
The market is growing for solutions that require fewer cameras and provide superior image quality. The potential for growth is large, as end-user awareness of panoramic and 360-degree imaging grows, Cargill said.
However, expectation management is crucial for panoramic and 360-degree cameras to flourish in the video surveillance market, Schaffer said. “The user should understand that panoramic and 360-degree cameras add value to their video surveillance system. They are not magical cameras that will replace fixed cameras, PTZ cameras and mini domes. You still need those cameras, but now you have a complete overview of the scene in question.”