Observation apparatus

Claim 2

Observation apparatus comprising: an array (40) of detectors positioned to receive radiation from successive predetermined sized portions of a scene during a plurality of exposure periods, wherein there is relative motion between the array and the scene, the detectors producing signals of magnitude dependent upon the intensity of radiation from the scene and the length of each exposure period during which the detectors are exposed to the radiation; characterized by first sensing means (74) responsive to the relative speed of the array and the scene, connected to the array to begin each exposure period at a time such that each successive portion of the scene to which the array is exposed substantially abuts the previous portion; and second sensing means (64) responsive to the intensity of radiation from each successive portion of the scene, connected to the array to end each exposure period at a time such that the signals produced by the detectors are below a predetermined limit.

Claim 3

Apparatus according to claim 1, characterized by transfer means (44, 46) connected to the array (40) and operable to transfer the signals from the detectors to output means (60).

Claim 4

Apparatus according to claim 2, characterized in that the transfer means includes a transfer gate (44) and a shift register (46) connected to the first (74) and second (64) sensing means to cause the transfer of signals to the output means (60) after the exposure period.

Claim 5

Apparatus according to claim 2 or 3, characterized in that subsequent to each exposure period a no exposure period occurs during which period any signals generated by the detectors (40) are discarded so as not to reach the output means .(60), the duration of the no exposure period varying with the relative speed of the scene and array and with the exposure period.

Claim 6

Apparatus according to one of the preceeding claims, characterized in that the first and second sensing means (74, 64) includes first signal generating means (86) connected to the transfer gate (44) to cause a first transfer of signals to the shift register (46) after the exposure period and to cause a second transfer of signals to the shift register at the end of the no exposure period.

Claim 7

Apparatus according to claim 5, characterized by second signal generating means (52, 56) connected to the shift register (46) to cause the transfer of signals from the shift register to the output means (60).

Claim 8

Apparatus according to one of the preceeding claims, characterized by selector means (56) connected between the shift register (46) and the output means (60) and connected to the first and second sensing means (74, 64) and operable to cause any signals produced by the detectors (40) during the no exposure period to be directed, by the selector (56), from the shift register (46) away from the output means (60) and to cause any signals generated by the detectors during an exposure period to be directed, by the selector (56), to the output means (60).

Claim 9

Apparatus according to one of the preceeding claims comprising a camera having an array (40) of CCD elements each of which operate to produce a charge of magnitude dependent upon the exposure time and intensity of radiation thereby, and the array transferring the charges on the CCD elements periodically to output means (60) so that the output means receives signals indicative of the radiation from successive portions of the scene, characterized by : radiation transmitting means (38) operable between a time T and a time T b to expose the array to radiation from a first portion of the scene; timing means (70, 86) operable subsequent to time T b to transfer the charge on the CCD array to output means; adjusting means (74, 70) responsive to the relative speed of the camera and the scene connected to the radiation transmitting means (38) and operable between a time T c and a time T d to expose the array to radiation from a second portion of the scene, the period between T b and T c being adjusted in accordance with the relative speed so that the first and second portions of the scene are substantially adjacent; and sensing means (64, 70) responsive to the intensity of radiation from the scene and connected to the radiation transmitting means (38) to adjust the period between time T a and T b and the period between time T and time T d in accordance with changes in the intensity of radiation from the scene so as to maintain the charge transferred to the output means proximate the predetermined average level.

Claim 10

Apparatus according to one of the preceeding claims, characterized by a CCD array (40); optical means (34) for directing radiation from the scene to the CCD array; a first clock (86); a second clock (88); a first shift register (46); a transfer gate (44) connected to the array (40), to the first clock (86) and to the first shift register (46) to transfer signals from the array to the first shift register upon receipt of a clock signal from the first clock, the shift register producing an output signal indicative of the transferred signals from the array upon receipt of a clock signal from the second clock (88); selector means (56) connected to receive the output from the first shift register (46) and operable upon receipt of an input signal to transfer the output from the first shift register to a resultant output (60) and to discard the output from the first shift register in the absence of an input signal; computer means (70); speed sensing means (74) connected to the computer means (70) to supply a signal thereto indicative of the relative speed of the camera and the scene; and intensity sensing means (64) connected to the computer means (70) to supply a signal thereto indicative of the intensity of radiation from the scene, the computer means having a first output (80) connected to the first clock (86) to vary the times of transfer of signals from the array (40) to the first shift register (46) in accordance with the signals from the speed sensing means (74) and the intensity sensing means (64), the computer means having a second output (58) connected to the selector means (56) to supply the input signal to the selector means in accordance with the signals from the speed and intensity sensing means.