Canon N656U, N1220U, N650U manual Adjusting the Threshold Value, To Set the Threshold Value

Page 48

S T E P 3

Adjusting the Threshold Value

When the scan mode is set to black and white, the image brightness can be adjusted. The threshold value setting determines whether a halftone will be expressed as a black or a white data point. The possible threshold values range between 0 and 255. Below a given threshold value, all data is converted to black. Likewise, all data with a value above the threshold is converted to white. Accordingly, higher threshold values produce darker images while lower threshold values result in brighter images.

Threshold Value = 128 (Standard)

Threshold Value = 180

Threshold Value = 70

To Set the Threshold Value

When the scan mode is set to black and white, click the [Tone Adjustment] button or pull down the Image menu and select [Tone Adjustment].

Drag the slidebar left or right to adjust the threshold setting.

Click the up or down arrow to increase or decrease the entry in the text box, or enter the value (0~255) directly from the keyboard.

After adjusting the threshold value, you can save the setting to a file under a file name and load the file again whenever you want to use the setting.

To restore the threshold setting to its default value, click this button.

Click the [OK] button.

The preview image will change to reflect the new settings.

48

Image 48
Contents Users Guide How to Make Best Use of the Manuals When you open the boxHow to Use this Guide Where to LookAbout the Conventions Used in this Guide Table of Contents Adjusting Scanned Images Installing Plug-in Module CS-U Operating EnvironmentControl Panel Features Image Size ppScanning Procedures E PPlug-in Module CS-U Special Features See the Results of Adjustments Immediately Dynamic PreviewGamma Curve Adjusts Image Brightness ColorSync Ver 2.0 + Compatible for Auto Tone CorrectionInstall Plug-in Module CS-U Quick Start InstructionsStart Plug-in Module CS-U Position materials for scanning and preview themVerify Image Quality with the Browser Function before Specify the Area of the Image to be ScannedClick on the Browser button Selection frame will appear Select the area to be scanned by clicking and draggingScan the Image p Save the Scanned Image pE P Displaying the Plug-in Module CS-U Control Panel RGB ValuesOperating Procedures Procedures Positioning OriginalsPlace the original on the scanners document glass Previewing Click on the Preview buttonSelecting the Output Device Setting the Resolution and Magnification Output Device Resolution= 720 dpi, Magnification= 100%To Set the Magnification Factor Set the desired magnification factor on the control panelSetting the Scan Mode Black and WhiteGrayscale Color DocumentsClick the arrow beside Scan Mode Select a scan mode from the pop-up menuVerifying the Image before Scanning To Verify the ImageRotating the Image Use these buttons to rotate the imageSetting Preferences Output DeviceAspect Ratio Unit Preview WindowReset Default Settings CalibrationClose Plug-in After Scan Operating Procedures Scanning Setting the Scan Area Position the pointer in the preview windowProcedures to Zoom ZoomingSelect the area you want to enlarge with the zoom function Click on the Zoom In button Scanning To Initiate the ScanSpecify the Scan Area Click on the Scan buttonSaving Scanned Images Enter a name for the file and click the Save buttonGrayscale, Color Photos and Color Documents Black & WhiteColor Photos and Color Documents Tone Adjustment Tone Adjustment DialogHistogram Settings How to Interpret HistogramsTo Adjust a Histogram How to Adjust HistogramsClick on the OK button Shadow MarkTone Curve Settings Manipulating the GraphTo Edit the Tone Curve Click the OK buttonRelationship Between the Tone Curve Image Brightness Value =Brightness and Contrast Settings ContrastBrightness To Adjust the Brightness and Contrast Adjusting the Color Balance Operating ProcedureGamma Value Settings Matching the Gamma Value to the Display CharacteristicsGamma value To Change the Gamma Value Settings Adjusting the Threshold Value To Set the Threshold ValueAuto Tone Correction To Set the Auto Tone CorrectionStandard ColorSyncUnsharp Mask Open the Image menu and select Unsharp MaskDescreen Open the Image menu and select DescreenSaving/Recalling Settings To Save Settings in a Settings FileClick the Save button To Recall a Settings File Matching Scan Resolution to Purpose Optical and Enhanced ResolutionsScanning Techniques Appendices Troubleshooting Problem Scan button cannot be selected Error Messages Error MessageCause ResponseGlossary Auto Tone CorrectionBits/Bit Numbers Black Eyedropper ToolColor Channel DotHistogram Image FileMagnification Optical Resolution ResolutionMoiré PixelScan Mode ShadowsThreshold Value Tone CurveIndex Output device 7, 11, 18, 25Page Canon Customer Support Help Desk Canon Computer SYSTEMS, INCOE-040AA 052000 CDS Canon Inc