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Main Dialog Window for PTShift


R, G, B checkboxes - These 3 checkboxes will allow you to select which color channels (Red, Green, Blue) are allowed to be shifted and which are not. When you press the 'Save dR' or 'Delete dR' buttons, only the selected color channels will be saved or deleted.

x, y, R - shown at the bottom of the PTShift dialog. When you draw a rectangular selection box on your image (say a 20 x 20 pixel box) and then start up PTShift, you will see the x,y location of the center of that box on your image. x is the horizontal, and y is the vertical. Both coordinates are in units of pixels. An x,y coordinate of 0,0 corresponds to the upper-left corner of your image. R is the distance of x,y from the center of the image (in units of pixels)

dR - dR is the amount that a color channel has been shifted at x,y in order to reduce the tCA. dR[User] is the dR value specified by the user. dR[PT] is the dR value calculated by PTShift to give the best fit curve that will satisfy all the dR[User] values specified at all the different control points.
  The dR[PT] value will only be displayed when the 'PanoTools Corrected Image' checkbox is selected.

< , > Buttons - Pressing these buttons will shift a color channel (Red, Green, or Blue) radially inwards or outwards by 0.1 pixels at x,y. The goal is to get the shifted channel to line up perfectly with the other 2 color channels at a given point x,y to reduce the CA at that point x,y.
  Pressing the  >  button will cause the chosen channel to be shifted radially outwards at x,y from the image center, and dR will increment by 0.1 pixels. Pressing the  <  button will cause the channel to be shifted radially inwards at x,y towards the image center, and dR will decrease by 0.1 pixels.
 
<< , >> Buttons - These buttons will shift a chosen color channel by 0.5 pixels. The  >>  button will shift a color channel radially outwards at x,y by 0.5 pixels. The  <<  button will shift a color channel radially inwards at x,y by 0.5 pixels.

  The 4 channel shift buttons ( <<  < > >> ), will not immediately give you an accurate view of how well your dR[User] removes tCA. When you press the '>' button, for example, the dR will increase by 0.1 pixels yet you will not see any apparent change in your image. The reason for this is that adjacent pixels in your image are apart by a distance of ~1 pixel, and PTShift is therefore only capable of shifting a channel in 1 pixel increments. So, using the 4 channel shift buttons to achieve a 0.1 pixel change in dR[User] is only a theoretical construct at this point rather than an accurate visual result.
  Fortunately, when you press 'Save dR' and select the 'PanoTools Corrected Image' checkbox, PTShift will then show you an accurate view of how well your chosen dR removes tCA at x,y.

Pref Button - Will open up the PREFERENCES window, which allows you to change the user preferences.

Zoom- Button - Zoom out from the rectangular selection box.

Zoom+ Button - Zoom in on the rectangular selection box.

Zoom+/- Button - Press the button once, and you get a zoomed in view of the selection box. Press it again, and you get a full view of the entire image. This button allows you to toggle between a zoomed in and a zoomed out view.

Toggle dR Button - toggles the dR values. If dR = 2 and you press the button, then you will get dR = 0. Press the button once more and you get dR = 2 again. This button lets you easily undo and redo a channel shift at x,y so you can see the difference in the image between your chosen shift dR and no shift at all.

Save dR Button - Will save the dR value for the selected color channels (chosen by the RGB checkboxes) and stores it in a text file in the same folder as your image. A box will be drawn around the control point on a separate 'Control Points' layer by PTShift. If you attempt to save a control point at x,y when a control point has already been saved at x,y then the new control point will replace the old control point.
   If you press the Save dR button while the PanoTools Corrected Image checkbox is selected, then the PanoTools Correction plugin will automatically run on your image using your saved dR.

Delete dR Button - Delete the dR values for the selected color channels for any control points within the selection box (drawn by the Photoshop Marquee Tool).

Find x,y Button - Find any control point located within the selection box, and display the dR channel shift for that control point. If there are no control points found within the box, then find a control point anywhere in the image.

Show Boxes / Hide Boxes Button - Each control point at x,y that you save will have a corresponding box drawn around x,y on the 'Control Points' layer. This button will make the boxes visible or invisible.

Info Button - Will open up the CONTROL POINT INFO window, which displays information on all of the control points for a given color channel (Red,Green,or Blue). This window also allows you to navigate to other saved control points.

SAVE abcd Button - Save the abcd values for all 3 color channels into a file. This file can be loaded by the PanoTools Correction plugin and run on your image to remove Chromatic Aberration.

PanoTools Corrected Image checkbox - When you select this checkbox, PTShift will calculate the best fit abcd for all 3 color channels. Then it will run the PanoTools Correction plugin on your image using the abcd values. If you now repeatedly press the 'TOGGLE dR' button, you can see the difference between your uncorrected image and the PanoTools corrected image.

[Note for Windows users: the very first time in a Photoshop session that you select this checkbox, the PanoTools Correction plugin gui will pop up on your screen. Simply press the 'OK' button and the plugin will run.
  Also, using this checkbox will cause the PTShift abcd values to be saved in the PanoTools plugin. When you exit PTShift, you can start up the PanoTools Correction plugin and verify that the abcd values are indeed stored in the plugin.
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X Button - Exit the script. ESC key will also exit.

Note: you can use multiple images in the same folder to specify control points, and those points will all be stored in the same data file in that folder. So if you load another image (with the same image width, height, CA, fstop, etc...) from that folder into photoshop, the 'SHOW BOXES' button will draw all the boxes representing control points, even if those points were specified in a different image in that folder.


Preferences Dialog Window


This window appears when you press the 'PREF' button in the main PTShift window.

Size of Control Point Boxes - Every time you save a control point, a colored box will be drawn around that point (on the 'control points layer'). This option will allow you to adjust the size of the boxes that are drawn on the control points layer.

Image Baseline abcd - In most cases, you will leave this checkbox unchecked. This will mean a default baseline abcd = 0 0 0 1 for your image. What is the baseline abcd? It is the abcd values that will be given to the color channels that are not shifted.

  For example, let us say you only shift the Red channel (so the Green and Blue remain stationary). Let us also say that you choose baseline abcd = (0 -0.03 0.0002 1.0298). This means that when PTShift tries to line up the Red channel with the Green,Blue channels (to remove tCA), it will apply the abcd=(0 -0.03 0.0002 1.0298) to the Green, Blue channels and then try to find the abcd for the Red such that all three channels line up.


Control Point Info Window


This window appears when you press the 'INFO' button in the main PTShift window.

Note that any buttons in the CONTROL POINT INFO window will not edit any control points or their dR shift data. This window is mainly just for viewing control point data and calculating the final a,b,c,d parameters.

The central area of this window will list all the CONTROL POINTS, their X,Y locations, DISTANCE FROM CENTER (distance of each control point from the image center), channel shift amounts specified by the user ( dR[Us] ), channel shift amounts calculated by PTShift ( dR[PT] ), and the DISTANCE ERROR ( dR[PT] - dR[Us] ).

RGB radio buttons - allow you to choose which color channel data to display in the table (Red, Green, or Blue).

Zoom+ Button - Zoom in on the rectangular selection box.

Zoom- Button - Zoom out

Show Boxes / Hide Boxes Button - Each control point at x,y that you save will have a corresponding box drawn around x,y on the 'Control Points' layer. This button will make the boxes visible or invisible.

Toggle dR Button - Toggle the channel shift between dR and 0. Let us say that dR = 2. When you press the button, then dR will go to 0. Press it again, and dR will go back to 2.

Goto Point # Button - You can type in the control point # in the adjacent text field, and then this button will cause that control point to be displayed. The dR at that x,y, location will be applied so that you can see what the channel shift will look like at that point. If there are control points for different color channels at the same x,y location, then the dR channel shift is displayed for ALL channels at that x,y point.

Prev Button - Display the previous control point listed in the data table of the INFO window.

Next Button - Display the next control point listed in the data table of the INFO window.

PanoTools Corrected Image checkbox - When you select this checkbox, PTShift will calculate the best fit abcd for all 3 color channels, and then run the PanoTools Correction plugin on your image using those abcd values.

SAVE abcd Button - Save the abcd values for all 3 color channels into a file. This file can be loaded by the PanoTools Correction plugin and run on your image to remove Chromatic Aberration.

Control Point Button - Sort the list of control points from 0 to N.

Distance from Center button - Sort the list by distance R from the image center.

Distance Error Button - Sort the list by distance error ( dR[PT] - dR[Us] ).

Delete All Button - Delete ALL control points for the given color channel