SPOT 4.1 Basic and Advanced Software Manual for SPOT Insight ...

Ch. 5 – Preparing to Take a PictureTable 5- 1: Gain SettingsNote: If you select 36 bpp as the pixel bit depth, Gain values/Gain Limits of 16 are not available.Gain Limit Possible Auto –Gain SettingsExposure Time(dim images)Background Noise(dim images)1 1 Longest Lowest2 1, 2 4 1, 2, 4 8 1, 2, 4, 8 16 1, 2, 4, 8, 16 Shortest HighestTable 5- 2: Relationship Between Gain, Exposure Time and Background NoiseTo set the Gain Limit, follow these steps:1. Ensure that the camera is set to use the Auto-Exposure option.2. Click on the Gain Limit select list, and select the number that you want to limit the gain to.For more information on the concept of gain, refer to Appendix A: Electronic Imaging Theory and theSPOT Insight Camera.Minimum ExposureAlthough the auto-exposure feature will selectthe best-calculated exposure time for you, youmay find it preferable to set a minimum exposuretime to allow certain areas of the image to bebrought out. In those cases, the user can selectthe Minimum Exposure checkbox in the Autoexposurewindow. The value box next to thecheckbox must then be filled in with a value inthe range from 0 to 1000 milliseconds.Exposure Limits - MinimumBecause SPOT Insight cameras are capable ofextremely short exposure times, light sourceswith intensities that vary with the waveform ofthe 60 Hz line supply (e.g., fluorescent lamps,120 volt incandescent bulbs, and 6 volt 20 watthalogen lamps) can cause the Live Image windowto flicker and result in incorrect brightness andcolor balance readings in captured images. The Minimum Exposureoption allows you to correct for these problems by limiting the camerato a minimum exposure time that is greater than the pulse interval ofthe light source. Consider the illustration to the right. In this case, thepulse interval of the fluorescent light source is 8.3 ms. Entering aFigure 5- 3: Setting a Minimum Exposure to AccommodateVaried Light Sources (Advanced Mode)Note: For countries with 50 Mhzpower line frequency, a minimumexposure of 30 ms is recommended.User Guide to the SPOT Insight Camera 97