Changes between Version 23 and Version 24 of Tutorial/ImageDisplay

Sep 19, 2013, 5:50:56 PM (10 years ago)



  • Tutorial/ImageDisplay

    v23 v24  
     1= [wiki:Titorial] / Image Display =
    2 = Opening an image =
     3== Opening an image ==
    35First download and unzip the folder UVMAT_DEMO01_pair containing the demo files (accessible on
    1416The box '''[!NomType]''' indicates the convention for indexing, here using a separator '_'. It shows the first term in the series, which is '_1', while '''[!FileIndex]''' is incremented when we move to frame_2 or beyond.   
    16 = Brightness and contrast =
     19== Brightness and contrast ==
    1721The frame '''[Scalar]''' on the right hand side indicates the number of pixels (1008, 301) ('''[npx, y]''') along the x and y directions, as well as the min and max brightness of the image (0 and 255). It is possible to change the brightness and contrast of the image display by setting values for these extrema. Pixels with brightness larger than the maximum will appear in white while pixels with brightness lower than the minimum will appear in black. The image histogram (number of pixels for each brigthness value A), is given in the lower left graph.
    19 = Zooming =
     24== Zooming ==
    2026When '''[zoom on]''' is selected (tag='''[!CheckZoom]'''), zoom in by pressing the left side button of the mouse on the image and zoom out by pressing the right button. Use the key board directional arrows to adjust the field of view. It is also possible to manually write the coordinate limits by editing the boxes '''[MinX][MaxX]''' and '''[MinY][MaxY]''' in the frame [Coordinates]. To come back to the whole image, unselect the check box fix ('''[!CheckFixLimits]''').
    2632Edit boxes in the GUI can be also zoomed by right hand mouse button selection: a new window appears with the tag name and content. This is convenient when a text box content exceeds its frame limits (for instance !RootPath).
    28 = Extracting data =
     35== Extracting data ==
    2937The current mouse coordinates in the image, as well as the local image intensity ('A'), are displayed in the upper right text window. The local image matrix  indices 'i' and 'j' are also displayed. By default the coordinates are expressed in pixel units, with origin (0,0) at the lower left of the image (the lower left pixel centre is at (0.5,0.5)). The x coordinate is equal to i-0.5 while the y coordinate is npy-(j-0.5), since the  image index j runs from top to bottom unlike the coordinate y. In case of low screen resolution, it is possible to duplicate this display in a bigger window, by right mouse button selection (after zoom has been desactivated). When the mouse is over an edit box or press button, its tag is displayed with a short explanation (tooltip). The tag and box string can be also displayed by selection with the right hand mouse button.