With the development of technology, the pixel pitch of the detector is getting smaller and smaller, and the pixel pitch has been reduced from the original 30 μm to 15 μm, or even 10 μm. The combination of a small pixel detector and a long focal length lens provides hardware guarantee for obtaining high-resolution images from a long distance.
Small pixel detectors are difficult to achieve high-speed imaging of targets while providing higher spatial resolution. In high-speed imaging, the integration time is very short, so the camera needs to capture as much light as possible as quickly as possible, which requires larger pixels. However, most applications for long-distance imaging do not require high speed, and objects moving at a distance will not move on the detector as quickly as near objects. Therefore, a smaller pixel size is generally acceptable.
Temporal and Spatial Position Information (TSPI)
The focal length of the lens is a key factor for long-distance imaging. When detecting and identifying targets of different types and different distances, the focal length of the equipment required is also different. If the size of the target has been determined, the user can calculate the distance of the target through the known focal length. When an object is moving, such as an airplane moving toward or away from the observer, the advantage of using a continuous zoom lens with excellent parfocality is very obvious.
In this way, the target can be tracked at every point in time, and this information can be saved as part of the source data of the image, thereby providing a key TSPI for the target. The effective focus output can tell the user the distance of the target, and the user can even judge the size of the target according to the percentage of the field of view it occupies.
For TSPI time information, users can connect the camera to a device that provides IRIG-B time code, and the IRIG device provides a reference for time synchronization. For example, IRIG-B provides signals at a rate of 100 pulses per second. By bundling IRIG-B with a camera with a continuous zoom lens, users can know the distance of their target at any given time.