Digital Camera Features      VideoCamera Features

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Long Exposures:  Up to 15 second exposures can be programmed for night time imaging or for cntrolled lighting situations.  For example, during the exposure, strobe lights (LEDs) can be triggered at variaous sequences.

Seek Exposure:  Regions of the image can be selected for which the average brightness can be computed.  By using seek exposure, the camera will take an image, compute the brightness in the selected region and adjust the exposure accordingly to obtain the desired level of exposure.  This is an interative process, but is very effective and accurate in low light scenes.  Image stacking can be enabled by which multiple 15 second exposures are taken and summed (stacked) in such a way that the colors are perceived correctly.  This is a technique developed in the astronomy field.

Burst Sampling:  Five images taken in about 1.5 seconds can taken, downloaded to the computer, and archived to disk.  This process can be repeated every 8-15 seconds depending on the capture resulution, which impacts how long it takes to process and write the images to the media card.  Optionally, this set of 'burst' images can be formed into an averaged image and a variance image.

Continuous Shooting To Media Card:  The Olympus cameras (SP350 and SP500) can be setup to shoot continuously to the media card. Using a 1 Gigabyte card, the camera can shoot approximately 2500 high quality JPEG images at 1024x768 at an interval of 1 image every 3.4 seconds.  At the end of the burst, the images are transferred to the computer, optionally labeled amd archived to disk.  Optionally the average and variance image can be computed, labeled and archived also.  A wmv movie can also be created from the images captured at selectable resolution and quality. 

Continuous Shooting to Disk:  A disadvantage of shooting to media card is that you have to stop shooting every so often and download the images to the computer for archiving.  This can take from 4-15 seconds per image, so if you shoot 300 shots over 20 minutes, the program will have to spend about 20 minutes downloading the images to the computer.  The alternative is to shoot continuously to hard disk.  The speed obtainable here is from one image every 10 seconds for 1024 x 768 to one every 30 seconds for the highest resolution.

Averaged and Variance Images:  Any sequence of images can be averaged together, and the variance image computed.  The sequences can be chosen from any scene and cove any interval of time up to the present.

Fastest Averaging Possible:  Coastal Study projects often want an 'averaged' image, 10-20 minutes long, of near shore conditions in order to help identify shoreline position and also get an indication of where the submerged sandbars are, and where rip currents are most likely to be found.  The faster images can be taken, the better the average comes out.  Unlike video cameras, capturing from digital camera is slow, but the spatial resolution can be up to 20 times greater.  The fastest speeds obtainable are about 1 image every 3-4 seconds for a resolution of 1024x768, and one image every 4-5 seconds for the highest resolutions (2816x2112 for the SP500).  Averaged images formed this way por periods of 10 minutes or more appear very similar to those obtained using a video camera and faster sampling.

High Resolution Time Lapse (wmf file) Creation: Timelapse videos can be made automatically on schedule from any sequence of images.  The sequences can be chosen from any scene and cove any interval of time up to the present.  Selecting images at various intervals during the time period is also possible. For example, if you have images taken every 5 minutes for the past 6 months, you can make a video of hourly values (or whatever) covering the last 60 days (or whatever) of work.

Continuous Shooting to Disk AND High Resolution Time Lapse (wmf file) Creation:  Since making the wmv video can be time consuming (up to a few hours), it may be desirable to shoot images while at the same time preparing a video of the past few hours.  This can be easily done by running 2 instances of VM95 from different directories.  One instance just snaps pictures and archives them to disk.  The other instance, setup for the same archive, runs the operations pertaining to making the wmv videos and uploading them to a web site.  In this manner, your imagery will be up to date online, and you can be posting the time lapse movies to the web, and still shoot continously to disk so there will not be any gaps in the image collection due to scheduled post processing and uploading activity.