How to choose the right camera for your Automotive Application
By: Photron USA, Inc.
Automotive engineers are continually faced with new vehicle safety requirements and highway emissions standards. The ever-changing automotive industry therefore requires the most advanced imaging systems to analyze video of everything from onboard and offboard vehicle safety tests to static airbag deployments to combustion events. Utilizing high-speed cameras allows engineers to record and examine both dramatic and subtle motion details by capturing anywhere from 1,000 to 20,000 frames per second (fps) at full resolution (generally 1-4 megapixels), with the highest performance cameras capturing in excess of 2M fps at reduced resolution.
Frame rate, pixel resolution, light sensitivity, physical size and weight, mechanical durability, internal battery backup and fast image transfer to nonvolatile memory are the most important high-speed camera features for automotive crash testing. Frame rate, pixel resolution and light sensitivity are the most critical features for combustion studies. Combustions studies often require a much higher level of camera performance than is needed for automotive crash testing.
Frame rate. For automotive crash testing, cameras are typically run at frame rates between 1,000 and 4,000 fps to meet automotive safety compliance standards. Combustion studies, on the other hand, often require frame rates of 20,000 fps or higher to capture the extremely rapid expansion of burning fuels.
Pixel resolution. The size of the field of view of the camera greatly influences the resolution requirements in any application. For instance, it is desirable to capture two-megapixel (1080 HD) images with an offboard camera in an automotive crash test because the field of view is typically quite large. One-megapixel (or smaller) images are often adequate for onboard cameras because of the smaller field of view.
Light sensitivity. In any high-speed application the camera’s light sensitivity impacts a great many things including the ability to use a short exposure time to eliminate motion blur, the ability to focus on objects that are varying distances from the lens, and overall image quality. Light sensitivity is especially critical in combustion studies where high frame rates and extremely short exposures are required, and where it is sometimes necessary to identify subtle changes in color.
Size/weight and mechanical durability. Onboard crash testing requires a small and lightweight camera that can fit into confined spaces. A small camera can be self-contained (i.e. all of the electronics are in a single housing) or tethered to a separate processor that can support multiple extremely small camera heads. The camera (and processor) must be extremely durable and capable of withstanding very substantial G-forces.
Internal battery backup and fast image transfer to nonvolatile memory. Onboard crash testing involves violent accelerations, decelerations and collisions that have the potential to disrupt power to the camera. Therefore, a built-in battery providing sufficient power to allow the rapid transfer of captured images to internal nonvolatile memory is essential.
Automotive testing environments can be very challenging for high-speed camera suppliers. To guarantee the successful implementation of high-speed cameras within such environments it is important to select an experienced supplier who can provide a broad range of highly-reliable cameras along with exceptional customer support.