| 摘要 |
Apparatus and method suitable for reducing the data compression and data transmission processing in a moving object imaging system as employed in an aircraft flyover ISR (intelligence surveillance and reconnaissance) system 100. This involves transmitting 109 a portion (figures 3) of the captured image pixel data (figure 2) within a frame, whereby the portion represents the pixels (130, 132, 134, 136 figure 3) which differ from that of a previous set of frames (T1-T2 figure 3). Each sensor pixel is identified with a given area on the underlying ground (surface) or surface resolution cell (L1,W1 figure 2). In one embodiment the controller 105 controls either the velocity or the distance of the image sensing system 102 relative to the surface S1 and/or regulates the rate of recording of the pixel frames (frame rate). The controller signal may be based on the requirement that each recording time interval is substantially equal to or an integral multiple (1 <=m< M) of the time it takes for the imaging system to move along the distance L1 associated with the surface resolution cell, in the direction of travel D. Here m is less than the effective number of pixels M in a row identified as being aligned in the direction of travel. In this case, by synchronising the frame rate with the stepwise extension of the pixels 118a-d, pixel redundancy is identified in the image captured in adjacent pixel cells of consecutive image frames (figure 4), thus lessening the burden of post imaging data compression and transmission. In other embodiments the method may include generating control signals to control a velocity of an image sensing system based on a rate of recording pixel frames (frame rate) in the image sensing system. In addition or alternatively the control signal may control the pixel frame rate based on the velocity of the sensing system, and may further control the distance of the sensor from the surface. The method may involve prior determination of the vehicle velocity and altitude by means of a satellite navigation system (GPS). The imaging vehicle may also be a drone, UAV or a satellite platform. |
