The Digital Sight camera system is equipped with a selection of tools that enables the microscopist to utilize an overlay function to place text and other annotation information, and to make measurements, on a photographed image. The capability of superimposing images for comparison is also provided, and overlaid information can be pasted onto and saved with the image. Additionally, a remote user may annotate an image through the Digital Sight's Internet browser interface, allowing for simultaneous interaction among multiple users of the system.

The tool functions of the Digital Sight camera system are displayed by selecting the TOOL tag from any menu. The various functions that are accessible from the menu are described below, and the control buttons referenced are illustrated in Figure 1. A mouse is required for almost all operations performed from this menu, and each function relies on a basic sequence for creating an overlay, which can be thought of as a transparent sheet placed over the image. Overlays are created by choosing the function (such as pen or text), drawing or entering text, followed by pasting to fix the overlay to the image. Corrections or redrawing require clearing the current entries before redoing either function. The Clear All button is pressed to erase information created in an overlay, and when pressed, requires selecting Y (yes) or N (no) to confirm the selection. Information added to an overlay through any of the provided tool functions is held in temporary memory until it is fixed to the image by pasting. Once the overlay is fixed, it can be displayed or hidden by pressing the Overlay ON/OFF button. Overlay ON enables display of the overlay on top of the image; Overlay OFF disables display of the overlay. An overlay cannot be partially erased, and using the Clear All feature will erase all text, markers, and superimposed objects.

The annotation tools provided by the Digital Sight system allow text, drawing, or counting markers to be entered for display as an image overlay. The pen function enables free-form drawing on the image, and is selected from the tool menu by clicking the Pen button. Figure 2 illustrates the function being employed to encircle several features on a digital photomicrograph with green lines. When the pen function is active, a small tool bar is displayed within the image window (Figure 2). The red, green, and blue button icons allow selection of the pen color, and drawing is performed by holding down the mouse button while dragging the pen pointer. Clicking the Clear button erases any lines drawn that have not been pasted into the image. When drawing is complete, the Paste button is clicked to fix the drawn information. Once the information entered on the overlay is pasted, erasing cannot be done without erasing the entire overlay. Selecting the return arrow icon closes the tool bar and returns to the previous menu, erasing any drawing that was not pasted.

The text function allows entry of text comments into an image overlay. Clicking on the TEXT button will display a tool bar for entering characters that are to be positioned on the image. Figure 3 illustrates these controls and an example text overlay on a specimen image. On the tool bar, three color buttons allow choosing the text color, and clicking inside the text entry field will display a keyboard on the screen for character entry. Following text entry from the keyboard screen, the Ent key must be clicked to confirm the entry. To position the entered text in the desired location on the image, the Position control is selected to display a text embedding area, which is then positioned by dragging with the mouse. Once the position has been determined, pressing the Paste button inserts the text in the chosen position (see Figure 3). Clicking on the return arrow closes the text tool bar and returns to the previous menu.

A count marker function, accessible through the TOOL menu, provides the microscopist with a convenient mechanism for marking and counting specific features of an image. When the Marker button is selected, a tool bar is displayed, as illustrated in Figure 4. After pressing one of the color buttons to select red, blue, or green markers, clicking any position on the image screen places a numbered marker of the selected color on the image overlay. Numbers are incremented sequentially from 1-99 as markers are placed, and the count for each color is displayed on the markers and also next to the corresponding color selection button. The marker color can be changed during counting by selecting a different color icon, and the count for each color will be maintained, and resumed at the previous count when returning to a color. The Undo and Redo buttons can be used to cancel or redo the most recent action. Up to 10 previous actions are retrievable. The Clear button will erase all markers that have been entered without activating the paste function. To save the entered markers as valid data, the PASTE button should be pressed. The return arrow serves to close the tool bar and return to the previous menu.

The Digital Sight camera system provides the ability to save seven length calibration reference values for use in measuring feature sizes on the displayed image. Once they are saved, the calibration values are recalled by selection of the corresponding menu button, numbered s1-s7 in the TOOL menu. This feature allows values to be saved for seven measurement conditions, such as the use of different objectives or microscope imaging configurations. The calibration and measurement procedures are separate processes, and are accessed utilizing the Calib. and Measure buttons in the TOOL menu. Measurements cannot be performed unless the calibration process is completed using a known size reference specimen.

To begin the calibration procedure, one of the custom calibration buttons (s1-s7) is selected, into which the reference value will be saved. Pressing the Calib. button displays a calibration screen similar to the one illustrated in Figure 5. A calibration line should be drawn corresponding to the length of an object of known length to be used as a reference. This is done by clicking one end of the object, and while holding the mouse button, dragging the line to the end point, then releasing the mouse button. The Clear button is used to erase a line just drawn. The next step is to click the number input box on the left end of the calibration tool bar, followed by entering the numerical length of the reference line just drawn using the numeric keypad. After clicking Ent., select the unit of measure by clicking the appropriate checkbox. Information about the calibration, such as a magnification value, can be entered by clicking the description box and entering the desired information. After verifying that the calibration memory number is correct, the Save button can be pressed to store the calibration value for future use in making measurements. Pressing the return arrow closes the tool bar and returns to the previous menu. Calibration values will be lost at this point unless they have been saved by pasting.

Measurements may be performed on a displayed image by recalling one of the saved calibration values, chosen by clicking on one of the custom calibration setting buttons (s1-s7) in the TOOL menu. As the mouse pointer is positioned over the custom buttons, information saved with that value is displayed in the Info: area at the lower edge of the menu. To display the measurement function tool bar, the Measure button is pressed. Figure 6 presents an example of the tool bar and a measurement line overlaid on the image. On the tool bar, three color buttons are provided for choosing the color of the measurement line to be drawn. Lines are drawn spanning features to be measured utilizing the same mouse-dragging procedure described above for the calibration step. Nine measurement lines may be drawn for each of the three color choices, and a number from 1-9 is assigned to each line. The calculated measurement for each line is displayed adjacent to it (determined using the calibration value chosen in the first step). The Undo, Redo, and Clear buttons have the same functions as previously described for the calibration function. Measurement lines can be saved to the image overlay by selecting Paste after the lines are drawn. If the return arrow is selected to return to the previous menu before pasting, the measurement lines will be lost.

A crosshair, or crossline, can be displayed on the image screen as an aid in adjusting the horizontal and vertical position of a specimen. Pressing the Cross button toggles between OFF and ON states of the crosshair display. When ON is selected, the crosshair is displayed in a fixed position at the display center, and can be displayed in two styles - across the full dimensions of the image or restricted to the central area. The color and style are changed by clicking the Color button, which cycles through a sequence of seven colors for each of the two styles.

The Scale ON/OFF button enables or disables the display of a reference scale on the image screen to allow determination of approximate feature sizes. After selecting a saved calibration setting (s1-s7), clicking the Scale ON button displays a scale based on the chosen calibration value. Selecting Scale OFF by clicking with the mouse turns off the scale display. In the system default state, the scale is not written in the saved or printed image. If the user wants the scale to be saved with the image data, the Scale check box should be selected on the REC menu.

The Digital Sight Tool menu provides an image superimposition feature, which allows creating a translucent overlay from any image displayed on the screen to be viewed superimposed over the live microscope image for comparison. The size range over which the image superimposition feature can be employed is one-half the display screen size. To initiate the process, the Create button in the Superimposition area of the menu is pressed, displaying a tool bar and a yellow-bordered area on the screen (illustrated in Figure 7). Clicking the mouse pointer inside the bordered area allows it to be dragged to the desired region for creation of the translucent image overlay. Pressing the Create button on the tool bar starts creation of the superimposed image, which takes a few moments. If the image created does not have sufficient contrast for easy recognition, the Clear button will erase it, and the level of opacity may be changed by increasing the Lev: value (Lev:1 - Lev:3), followed by using Create to re-create the image. When the desired contrast of the translucent image has been obtained, pressing Save will save the image in the system's internal memory and return to the TOOL menu. The Disp. button causes the saved translucent image to appear in the overlay with a menu bar providing the option of pasting the image into the overlay.