Time lapse video capture information
I used a Sharp VHS camcorder altered for time lapse capture and control from a datalogger by Chris Ellis at St. Anthony Falls Lab. For runs 1 and 2, the video shot through rainfall. For subsequent runs, I installed a datalogger-controlled solenoid valve on the rainfall water supply to shut of rain for a few seconds prior to video recording for a clearer shot of the basin surface. After each run, the analog VHS signal was converted to a digital signal with Adobe Premier, subsampled, and compiled into Cinepak format video clips. Original frame size is 640 x 480 pixels. I reduced frame size for run 6 to 320 x 240 to decrease clip size.
| run # |
capture rate (seconds of runtime / frame)
|
vertical erosion/frame (cm/frame)
|
| 1 |
162
|
0.035
|
| 2 |
983
|
0.28
|
| 3 |
139
|
0.08
|
| 4 |
3563
|
0.20
|
| 5 |
1860
|
0.27
|
| 5(knicks) |
620
|
0.091
|
| 6 |
380
|
0.036
|
page last modified June 5, 2001 by Les Hasbargen