Color Page

At the top of the tool page is the Image preview


Histogram

The histogram represents the distribution of the colors of the current image.

The value 0 is on the left side of the histogram and each vertical line is a range of 50 values for an image 3 x 8 bits.

For a colored image the grey curve represents the intensity histogram.

When the current image is transformated the new histogram is displayed.

histogramToolBox.png

Contrast - Brightness

The contrast and the brightness of the image can be adjusted with this tool.

To avoid under-exposing the dark zones of the image, a minimal value can be fixed in the entry Lower and the same parameter can be set for the hight value with the entry Upper. That's means if you fix a lower value of 50 and an upper value of 200 the filter will be applied only for the value into the range of 50 to 200. Into the histogram these values are represented by the first and the last vertical lines.

Enter the values of the contrast and the brightness with the sliders or the button + or - and click on the button Apply.

You can see a preview of the filter with the eye_red.png button.

You can reverse the transformation with the button Cancel.

The change appears into the Historic tool box.

contrastBrightnessToolBox.png

Contrast stretching

This is an other approach for the contrast adjustment.

This Filter is based on the work of IPOL

© 2009-2014, IPOL Image Processing On Line & the authors

Enter the lower and upper values into the entries. Use low values for the first test.

Due to the calculation mode this filter cannot be applied gradually, you have to cancel the effect before to try with other values.

You can see a preview of the filter with the eye_red.png button.

contraststretchingToolBox.png
stretchingSample.png

Example: The original image, on the left side, has been enhanced with 2 % for Lower value and 2 % for Upper value.

You can reverse the transformation with the button Cancel.

The change appears into the Historic tool box.



Denoising

New in version 2.1.

This filter is used to remove the noise of an image, this color defect is especially present into the image digitallized with a scanner.

Select the option Black & White if the image is a grey map.

The most important parameters are Template and Sample.

The value of Template is always odd and provide the best result if it is between in range 3 to 9.

The value of Sample is always higger than the Template value and provide the best result if it is between in range 6 to 12.

You can see a preview of the filter with the eye_red.png button.

Click on the Apply button to apply the filter on the image.

denoisingToolBox.png
denoisingSample.png

Example: The original image, on the left side, has been denoised with the value 7 for Template and the value 12 for Sample.

You can reverse the transformation with the button Cancel.

The change appears into the Historic tool box.



At the bottom of the tool page is the Historic tool box.