The Brightness/Contrast Adjustment option applies to color images only. The brightness and contrast of images are analyzed and corrected, based on contrast of objects and background consistency.
Contrast Limit
|
Option |
Description |
|---|---|
|
Dark |
Sets the maximum contrast change for dark pixels. Range 0-255. |
|
Middle |
Sets the maximum contrast change for middle-range pixels. Range 0-255. |
|
Light |
Sets the maximum contrast change for light pixels. Range 0-255. |
|
Option |
Description |
|---|---|
|
Target Brightness |
Sets the target brightness level for background of adjusted image. Range 0-255. |
|
Target Contrast |
Sets the target contrast between foreground and background for the adjusted image. Range 1-255. |
|
Target Variance |
Sets the largest allowable variance in brightness across the image. Range 0-255 |
|
Min. Percentile |
Sets the lowest brightness percentile pixels to target for adjustment. Range -1 to Max. Percentile. Default 0. This value sets the percentile brightness to be used for the contrast enhancement. For typical document images, the text color will be at or below the 1st percentile, so a value of 1 would push the text color to pure black. The value 0 means to use the darkest pixel found, and a value of -1 means that the brightness will not be decreased. |
|
Max. Percentile |
Sets the highest brightness percentile pixels to target for adjustment. Range Min. Percentile to 101. Default 100. This value sets the percentile brightness to be used for the contrast enhancement. For typical document images, the background color will be near the 50th percentile, so a value of 50 would push the background color to full brightness. The value 100 means to use the brightest pixel found, and a value of 101 means that the brightness will not be increased. |