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

Ch. 6 – Using Live ImagesLive Image Controls – Auto Exposure OptionsWhen you have selected auto-exposure in your image set-up, the Live Image Controls window will featurethe following options.BrightnessEnter a Brightness value between .25 and 32.A brightness value of 1, the default value, givesyou the correct image brightness for mostimages. The Brightness Adjustment controlallows you to overexpose or underexpose(darken or lighten) the image area. In manycases, an image has varying levels ofbrightness; to see a specific area better youmight want to lighten or darken the image.When using the Brightness control, the SPOTcamera uses an algorithm that combines gainand exposure time to provide the fastestpossible image update rate (shutter speed) inlive preview mode:• When overexposing images to make them brighter (i.e., entering values greater than one), the camerafirst selects the highest possible gain before lengthening the exposure time. Because gain alsobrightens an image, less exposure time is needed.• When underexposing images to make them darker (i.e., entering values less then one) the camera usesthe lowest possible exposure time before lowering the gain.Quality/SpeedUse the slider to balance speed and quality when previewing dim images.• Moving the slider toward the Quality side increases image quality and decreases frame rates.• Moving the slider toward the Speed side increases frame rates and decreases image quality.The Quality/Speed measurement corresponds to the Gain limit setting (see Ch. 5) on the Image Setupwindow, which allows you to set an upper limit on the gain options that will be available during the Auto-Exposure process.• When the slider is at the left-most point, the Gain Limit is 1, which restricts the camera to a gain of 1,giving you higher quality pictures, but lengthier exposure times.• When the slider is at the right-most point, the Gain Limit is 16, which allows the camera to select fromthe six gain options available in Live Image Mode. This shortens exposure times, but decreases imagequality.Note that the highest gain option, 16, is not an option on the Image Setup window, which featuresonly four gain levels, 1, 2, 4, and 8. While a gain of 16 might be too grainy for captured images, itcan be helpful in speeding the display of dim images in live image mode.For more details on setting a Gain Limit, refer to Ch. 5 –Preparing to Take a Picture. For more informationon the concept of gain, refer to Appendix A: Electronic Imaging Theory and SPOT Cameras.Auto-BrightnessAvailable only when you are using Auto exposure, the Auto-Brightness option enables you to maintain aconsistent brightness level for changing specimens.User Guide to the SPOT Insight Camera 119