The CAM menu of the Digital Sight camera system can be accessed by pressing the menu button on the camera control unit or by right-clicking with the mouse in the upper third of the display screen. If another menu is currently activated, switching is accomplished by selecting the CAM tab in the menu. Selection of the Easy tab provides a simplified method for capture of images by simply choosing an imaging mode appropriate to the specimen, and allowing the control system to determine optimum settings based on its programmed expertise. The advanced (Advn.) CAM menu provides all of the capabilities of the simpler menu, and also allows the user to individually adjust the camera settings for more precise image control.

Four display modes are provided that utilize different combinations of resolution, camera gain (sensitivity), frame rate, and color balance to suit varied specimen types and illumination conditions. Other variables that may be fine-tuned to optimize image quality through this menu include color balance and image contrast, as well as the mode of exposure determination and the photometry mode and area. Many of the operations in the system control menus are both right- and left-click sensitive, simplifying the setting of specific choices by allowing changing of the selection in the forward or reverse direction. For functions requiring value adjustment, such as the camera GAIN setting, left-clicking increases the value, while right-clicking reduces the value. In the case of the shutter speed setting, left-clicking reduces the shutter speed to increase exposure, and right-clicking increases shutter speed to reduce exposure. Mode selection buttons simply step through the mode choices in opposite directions with left- and right-clicking.

The Focus display located at the lower edge of the CAM menu (illustrated in Figure 1) indicates the relative quality of image focus (sharpness), represented by the number of segments displayed in the graphical bar. A numerical value for the focus rating is displayed to the right of the graphical indicator. Higher numerical focus ratings indicate better microscope focus for the specimen being viewed. In order to adjust the focus, and maximize the focus rating, the microscopist must raise or lower the microscope stage (or the nosepiece in some earlier models) using the coarse and fine focus knobs. The area immediately above the focus indicator serves as an Info Box for the display of information such as the selected scene mode or descriptive text saved when setting up a custom mode.

Figures 2 and 3 illustrate the two versions of the CAM menu that may be displayed when the Easy tab is selected. At start-up, the system will display either a Biological (Figure 2) or an Industrial (Figure 3) version of the menu, depending upon which is chosen for Cam OSD in the Power On Settings screen of the SETUP menu. The unique feature of either Easy menu is the inclusion of scene mode buttons that allow the microscopist to quickly set the camera control unit to a combination of image resolution, sensitivity, frame rate, and color balance that are appropriate to the specimen and illumination mode. The provided scene mode buttons in the biological display version are, from left to right, darkfield/fluorescence, brightfield, and differential interference contrast/phase contrast. In the industrial specimen interface, the selectable modes are, from left to right, wafer/IC chip, metal/ceramic, and circuit board. A brief description of the characteristics and general specimen types appropriate for each scene mode are listed below:

Biological Specimen Scene Modes

• Darkfield/Fluorescence: This mode is utilized for photographing specimens that have predominately dark backgrounds. A rapid frame rate is maintained to minimize time lag when focusing and positioning the specimen. High-resolution digital images may be acquired in this mode.
• Brightfield: This imaging mode is intended for conventional specimens that exhibit some contrast and that appear on a bright background. Most common specimens, such as stained biological materials, are suitable for viewing and image capture using this scene mode.
• Differential Interference Contrast/Phase Contrast: The image contrast is increased in this mode, making it advantageous for many contrast-enhancement techniques that do not rely on staining.

Industrial Specimen Scene Modes

• Wafer/IC Chip: This is an appropriate scene mode for general imaging of semiconductor wafer materials and integrated circuits (such as computer chips).
• Metal/Ceramic: Metal specimens examined in this mode will be rendered with bright areas as white and dark regions as transparent. The settings are also suitable for use with ceramic or plastic specimens.
• Circuit Board: This mode is intended to optimize images of component-fitted circuit boards when inspecting for mounting defects. Saturation, or clipping, of highlights in component leads and solder joints are suppressed by gamma (tone) modification in order to make defects detectable in such areas. The mode is appropriate for any specimen displaying excessive contrast when viewed in reflected light, such as metal gears and other highly reflective components.

The Exposure Mode button (Figure 1) toggles in sequence through the exposure modes provided by the camera system, enabling the desired mode to be selected. Each of the four available exposure modes is described in the Exposure and Camera Sensitivity section. The settings controlled in each of the modes accessible from the CAM menu are summarized below:

• PROG (program AE mode) - In the program auto exposure mode, the control unit adjusts both the shutter speed and camera gain to achieve proper exposure. The CMP. button (Compensation; see Figure 4) can be used to modify the nominal exposure over a range of -2.0 EV to +2.0 EV in 0.3 EV steps.

• S_AE (shutter speed priority AE mode) - The Shutter Speed button (Figure 5) is utilized in shutter speed priority mode to set the shutter speed within the range of 1/1000 second to 4 seconds. The CMP. button can be employed in this exposure mode to adjust exposure compensation over a range of -2.0 EV to +2.0 EV in 0.3 EV steps.

• MANU (manual exposure mode) - In the manual exposure mode, the Shutter Speed button (see Figure 6) can be used to set the electronically controlled shutter within a range of 1/1000 second to 60 seconds. The Camera Gain (C_gn.) button (also illustrated in Figure 6) becomes active (replacing the CMP. button) and may be used to set the camera gain to values ranging from x1 (C_gn. value of 100) to x46 (C_gn. value of 4600).

• F_AE (focus priority exposure mode) - The CMP. button (Figure 7) can be used in focus priority mode to change the exposure compensation over the range of -2.0 EV to +2.0 EV in 0.3 EV steps.

When set to any exposure mode other than manual, the Digital Sight camera control unit will automatically adjust the CCD exposure variables that are appropriate in the selected mode to maintain proper exposure of the specimen image. If movement or other specimen changes cause problematic exposure fluctuations, the exposure setting can be temporarily locked by use of the Auto Exposure Lock button (AE_L). When this feature is enabled, the camera control unit locks the current exposure settings, and the text on the AE_L button surface becomes red to designate that the exposure is being held fixed.

In addition to exposure mode controls, the CAM menu encompasses a number of features that are useful for performing digital image correction functions. Routine functions of the image correction controls accessible through the CAM menu (refer to Figure 1) are outlined briefly as follows:

• Gain Adjustment - The Y### button (where # represents the value of the Y, or luminance, component of the displayed image) controls the gain (brightness) of the displayed image and will be applied to captured images. The gain is referenced to a value of Y100 equal to 100 percent, and is variable in increments of 5 percent. Gain adjustments made through this control are effected at the digital output stage, and therefore the correction can be applied to frozen images as well as to the live display. The mechanism by which the gain control affects digital image appearance is discussed in the Image Correction Features section.
• White Balance Setting - Clicking the WB button will execute white balance adjustment for the current image field. Optimum color balancing of the CCD detector requires adjustment for correct exposure prior to setting the white balance on a uniform transparent or white area of a specimen, or with the specimen removed from the light path. White balance effects on digital image appearance are discussed in the White Balance Calibration section.
• Tone Setting - The TON# button (where # represents the tone setting number) will toggle through the seven available tone (gamma) settings. The various tone settings represent a range of gamma adjustments that may be applied to the digital image to control the image contrast, and facilitate obtaining optimum image quality from a wide variety of specimen types. A description of the individual tone controls and how they affect the appearance of the displayed image is discussed in the Image Correction Features section.
• Effects Setting - Clicking the Color button toggles through the five available color effects settings: Color, B & W (black and white), Nega, Blue Back, and Sepia. The color effects settings and their uses are discussed more thoroughly in the Image Correction Features section.
• Color Balance Adjustment - Two buttons, R### and B### (where ### represents the color value for the designated channel), corresponding to red chrominance and blue chrominance, can be used to adjust color balance of the displayed image. The 100-percent levels for the channels are referenced to R100 and B100, respectively. When these controls are used in combination with the gain button (Y), the image level and color balance may be adjusted to ideal levels prior to capture. The R and B color balance adjustments may also be employed to apply fine corrections to white balance following automatic setting. The effects of color balance modification on the appearance of the displayed image is discussed in the Image Correction Features section.
• Sharpness Adjustment - Left or right clicking on the SHP # button (where # represents the sharpness setting number) will toggle through the six available image sharpness settings, SHP0 to SHP5. The visual sharpness of the displayed image is increased by enhancing edges or contours of the image features, ranging in effect from 0 (off or no effect) to 5 (strong). Image sharpening is discussed in greater detail in the Image Correction Features section.
• Clear Button - The CLSet button clears changes made to CAM menu settings and restores the values previously saved in the active configuration.

The full spectrum of operational functions of the Digital Sight camera system are easily accessed through the CAM menu. By selecting the Easy tab, preprogrammed image modes are available that enable capture of excellent images with minimal input from the user. When full control of imaging variables is desired, the Advn. menu allows access to individual camera settings, and to real-time image enhancement features that take full advantage of the capabilities of the camera system.