CV-A11
6. Functions and Operations
Apart from the standard continuous operation, the
In addition, the
6.1. Basic functions
Some of the primary camera functions need a general introduction before the operation modes are described. The list below shows the primary functions from the command list.
SM | Shutter Mode | Normal shutter, Programmable Exposure |
SH | Shutter Speed | Off to 1/100,000 second |
PE | Programmable Exposure | 1.5 H to 1023.5 H |
SC | Scanning Format | Full frame, 1/2 partial, 1/3, 1/6 partial |
TR | Trigger Mode | Normal, Edge, PWC, frame delay readout |
|
| Long time exposure, |
HC | HD Accumulation | H Synchronous, H Asynchronous. |
The shutter SM can be set to normal (SM=0), where the exposure time is selected from 15 fixed step with the command SH, or programmable exposure (SM=1). Here the command PE allows 1023 step with 1 line period resolution (63.5 ∝s) in triggered mode. For normal mode, PE can be up to 523 for full, 275 for 1/2, 195 for 1/3 and 115 for 1/6 partial scan.
The CCD scanning format SC can be selected between full or partial scanning. With partial scanning, only the vertical central part of the CCD sensor is read out with a higher frame rate. The partial scan is done by a fast dump read out of the lines in the vertical ccd register down to the top of the partial image. The partial part of the image is read out with normal speed. The lines below the partial image are read out and dumped with a high speed.
Imaged scene |
| 648 pixels |
240 pixels | 160 pixels | 80 pixels |
1/2 PS, | 1/3 PS, | 1/6 PS, |
Partial scanning.
Aspect ratio correct
Fig. 8. Partial scanning.
The accumulation mode HC is H synchronous (HC=0). For PWC mode (TR =2) and Frame Delay readout (TR=3) it can also be set to asynchronous accumulation (HC=1).
In H synchronous mode, the exposure in will start at the first HD pulse after the trigger falling edge. In H asynchronous mode the exposure will start immediately at the leading edge of the trigger pulse without waiting for the HD. Fig. 9 and fig. 10 shows the details.
HD
Trigger 
Accum
X b
Fig. 9. PWC H synchronous accumulation.
HD
Trigger 
Accum
X b
Fig 10. PWC asynchronous accumulation.
In normal continuous mode (TR=0) shutter speed up to 1/100,000 second can be used. In triggered shutter modes, the shortest shutter time is limited to ≥1,5 H or 1/10,000. In triggered shutter modes with full and partial scan, the exposure time is not limited to the frame read out time. It can be longer.
- 6 -
