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

Ch. 5 – Preparing to Take a PictureBits per PixelBits per pixel (or Pixel Bit Depth) is the number of bits per pixel (bpp) that the camera uses to create animage. The SPOT program provides different options, depending on which Insight camera model you areusing.• Insight Color - 24 bpp and 36 bpp.• Insight B/W - 8 bpp and 12 bpp.• Insight 3-Shot – 8 bpp, 12 bpp, 24 bpp, and 36 bpp.Note: Insight Color users can use the Change Pixel Bit Depth option to convert the pixel bitdepth for a captured image to a monochrome setting.For Insight Color and 3-Shot users, the 24 bpp RGB color setting is the most common selection because itis an industry standard color format that is used by Windows and most printers. Most monitors cannotdisplay more than 24 bpp. Select a Pixel Bit Depth by clicking on the Bits per Pixel drop-down box. Inaddition to specifying the bits per pixel of the image, your selection determines the Gain and Gain Limitchoices (see appropriate sections in this chapter) as illustrated in the table below:Bits Per Pixel Camera Available Gain/Gain Limit Options8 B/W,3-Shot12 B/W3-Shot24 Color,3-Shot1, 2, 4, 8, 161, 2, 4, 81, 2, 4, 8, 1636 Color3-Shot1,2, 4, 8Note: When you select 8 or 24 bit, your options for saving a captured image include Bitmap,JPEG, JPEG 2000, Pict (Mac), TIFF (uncompressed) and TIFF-JPEG. When you select 12or 36 bit, your options are limited to TIFF(12 or 16 bit uncompressed and JPEG 2000.The following table lists the available image depth options and describes some of the potential uses,advantages, and disadvantages associated with each setting.Pixel Bit Depth Settings8 bpp (monochrome)Insight B/WInsight 3-ShotCharacteristicsThe 8 bit setting is often used in cases where 256 gray levels are adequate. Thelower number of bits per pixel results in smaller, more manageable file sizes.A typical 8 bpp image is…1.83 Mb12 bpp (monochrome)Insight B/WInsight 3-Shot24 bpp (RGB color)Insight ColorInsight 3-Shot36 bpp (RGB color)Insight ColorInsight 3-ShotThe greater number of bits per pixel in the 12 bit setting provides users with 4096gray levels. This provides a more accurate means of measuring brightness in amonochrome image, and helps to reduce banding problems that often appear whenan image is modified.A typical 12 bpp image is…2.75 MbThe 24 bit setting provides 8 bits per color, per pixel (i.e., 8 x 3 = 24). As noted, 24bpp is the most common choice because it is an industry standard in terms ofprinting, the Windows operating system, and monitor display.A typical 24 bpp image is…5.49 MbThe 36 bit setting provides 12 bits per color, per pixel (i.e., 12 x 3 = 36). 36 bpp isused in cases where images are heavily modified. The 36 bit setting provides userswith 4096 brightness levels per color and thereby reduces banding problems whenimages are stretched.A typical 36 bpp image is… 8.24 MbUser Guide to the SPOT Insight Camera 91