1. A method for thermal control of a digital imaging system comprising:
measuring a first dark current of the photo detector at a known temperature;
measuring a second dark current of the photo detector; and
calculating the temperature of the digital imaging system based on the first and second dark currents; and
reducing the temperature of at least one component in the digital imaging system if the calculated temperature is greater than a preselected value.
2. The method of claim 1, wherein the photo detector is a CCD.
3. A method of operating a digital imaging device, said method comprising:
measuring a first dark current of at least one photo detector associated with said digital imaging device;
measuring a second dark current when said at least one photo detector is at a preselected temperature;
calculating the temperature of said at least one photo detector based on said first dark current and said second dark current; and
altering the performance of at least one device associated with said digital imaging device based on said temperature.
4. The method of claim 3 and further comprising first photo detector of said at least one photo detector that is situated within said digital imaging device so as not to receive light, and wherein said measuring comprises measuring a first dark current of said first photo detector.
5. The method of claim 3, wherein said digital imaging device comprises a shutter, wherein said shutter controls the light received by said at least one photo detector, and wherein said measuring comprises dosing said shutter and measuring a first dark current of said at least one photo detector.
6. The method of claim 3, wherein said first dark current changes a preselected amount for a preselected change in temperature, and wherein said calculating comprises calculating the temperature of said at least one photo detector by measuring the difference between said first current and said second current, wherein said temperature of said at least one photo detector is proportional to said difference.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Articulated train rake, comprising:
a plurality of longitudinally aligned cars, each having leading and trailing longitudinal ends,
for each car a ball joint between the leading end of said car and the trailing end of the preceding car in the row,
each car comprising a body, at least a bogie on which the body rests, and pivot joint means for connecting the body to the bogie, characterised in that the ball joints are disposed at a vertical level lower than or equal to the pivot joint means relative to the rolling plane of the rake.
2. A rake according to claim 1, wherein the pivot joins means are such that the body is pivotally mounted on the bogie about an axis perpendicular to the rolling plane of the rake.
3. A rake according to claim 1, wherein each car comprises a single bogie supporting the leading end of said car, the trailing end of the car being supported by the leading end of the following car in the row via the ball joint.
4. A rake according to claim 3, and comprising, for each car, a walkway which causes an internal volume of the body of said car to communicate with an internal volume of the body of the preceding car, the ball joint between the two cars being disposed below the walkway.
5. A rake according to claim 4, wherein each body has a stepped bottom comprising leading and trailing bottoms located vertically relatively higher, relative to the rolling plane of the rake, and a relatively lower central bottom.
6. A rake according to claim 5, wherein the pivot joint means are disposed below the leading bottom.
7. A rake according to claim 5, wherein the bogie extends partially below the leading bottom and partially below the walkway, the ball joint being interposed vertically between the bogie and the walkway.
8. A rake according to claim 7, wherein the bogie of each car extends partially below the trailing bottom of the body of the preceding car.
9. A rake according to claim 4, wherein the internal volume of each body and the walkway causing this internal volume to communicate with the internal volume of the preceding body are delimited on one lower side by respective floors extending substantially at the same level vertically relative to the rake rolling plane.
10. A rake according to claim 1, wherein each bogie comprises two longitudinally spaced parallel transverse axles, the ball joint being disposed longitudinally between the two axles.
11. A rake according to claim 1, wherein the ball joint for connecting each car to the preceding car is disposed longitudinally at a distance of less than 2 metres from the pivot joint means between the body and the bogie of the car.
12. A rake according to claim. 1, wherein it comprises a pantograph capable of sliding along a catenary and disposed above one of the cars, vertically in line with the pivot joint means of this car.
13. Train car capable of forming part of an articulated rake comprising a plurality of longitudinally aligned cars, the car comprising a body, at least a bogie on which the body rests, pivot joint means for connecting the body to the bogie and ball joint means capable of co-operating with complementary ball joint means of the preceding car in the row in such a way that the cars are joined by a ball joint, characterised in that the ball joint means are disposed at a vertical level lower than or equal to the pivot joint means relative to the car rolling plane.
14. Car according to claim 13, and comprising, at a leading end, a walkway portion capable of co-operating with a complementary passage portion of the preceding car so as to create a passage which causes the respective internal volumes of the bodies of the two cars to communicate, the ball joint means of the car being disposed below the walkway.
15. Car according to claim 14, wherein the body has a stepped bottom comprising leading and trailing bottoms located vertically relatively higher, relative to the rolling plane of the rake, and a relatively lower central bottom, the pivot joint means being disposed below the leading bottom.
16. Car according to claim 15, wherein the internal volume of the body and the walkway portion are delimited on a lower side by respective floors extending substantially at the same level.