The Pick Points tool is used to create lists of points. Multiple lists may be created for each wavelength and time point.
Window Picking mode Wave Time List Npts Coordinates Name Color Marker Show all waves Show 3D points Check point Search method Box Range Load Save File format Copy Grid Key bindings
PickToModel | Clouds | Priism
Use this field to enter the number of the image window to be used for picking points.
This option menu controls what happens when the left mouse button is clicked in the image window. The options are:
Displays the index of the wavelength for the current list. When the image window is in pseudocolor mode, any change to the current wavelength will cause the current list and the Wave field to be changed; changing the Wave field in this case will cause the image window to display that wavelength. If the image window is in RGB mode, the current list and Wave field are not changed as wavelengths are mapped or unmapped; in this case, changing the value in the Wave field is necessary to switch between the lists in different wavelengths.
Displays the index of the time point for the current list. When the current time point displayed in the image window is changed, this field and the current list will be changed as well. You may change this value to change to the current list in a different time point and to cause the image window to display that time point.
The point lists for each combination of wavelength and time point (i.e. each x, y, z volume) are numbered from zero. This field shows the number for the current list. You may change this value to change to another one of the lists at the current wavelength and current time point or to create a new list.
The number of points in the current list is reported in this field.
The x, y, and z coordinates for the last point chosen are shown in the fields labeled X, Y, and Z, respectively.
Each point has an additional number, referred to as the name, assigned to it. This may be of interest if you want to distinguish classes of points within the same list: for instance if you choose to have Pick Points color points by their names. The value shown in this field is the name that will be assigned to the next point added by clicking in the image window.
When points are displayed in the image window, they are either colored according to the wavelength they are in or by the name assigned to each point. Use the Color option menu to choose between these two alternatives. If you color points by name, there are twelve colors available so the color of a point is the nth color where n is the point's name modulo 12.
All points in the same list are drawn using the same marker to identify a point's position. The marker for the current list is shown on the list marker option menu and may be changed using that menu.
If this toggle is on, points in all wavelengths are show and not just the wavelengths whose images are currently shown in the image window.
If this toggle is on, the z coordinate for a point is ignored for display purposes and the point is shown in all sections in the same wavelength and time point.
If this toggle is on, then when selecting points interactively, a new point will not be added if its coordinates match those of another point in the same list.
When points are added interactively, a local search and average is done to refine the coordinates of the point selected with the mouse. This refinement is not done if the search ranges are zero and the box size for averaging is one. For the local search, the Search Method option menu selects whether a search for a minimum or a maximum in the intensity (density) is done.
When selecting points interactively, a two step refinement of the selected position is performed which involves a search (see the topics Search method and Range) and a first moment calculation using the image intensities as the weighting factors. The moment calculation is done over a region nx by ny by nz pixels where nx is the value shown in the XBox field, ny is the value shown in the YBox field, and nz is one-half of the value show in the ZRange field.
When selecting points interactively, a two step refinement of the selected position is performed which involves a search and a first moment calculation using the image intensities as the weighting factors. The range of the search covers a volume nxy by nxy by nz pixels where nxy is one plus two times the value shown in the XYRange field and nz is one plus two times the value shown in the ZRange field.
Pressing the Load Points button will open a dialog for selecting a previously created points list file. The file must be in the old pick points format. If you already have point lists, you have the option to either keep or delete them when loading another points list file.
Pressing the Save Points button will open a dialog to enter the file name and file format to use. If the old pick points format is used, then if the sort by z toggle is on the points in each list will be sorted in order of increasing z coordinate before it is saved; otherwise, the order of the points is not modified.
Pick Points works with two file formats. One, referred to as the old pick points format, can be read and written by Pick Points and is also used in many other applications. The other, referred to as the new object library format, can be written by Pick Points and is used in Clouds.
Pressing the Copy... button will open a dialog to specify how to copy points which fall within a subset of the data set to another subset of the data set. The source and destination are specified as ranges in z and time and a set of selected wavelengths; the ranges appear in the dialog as the minimum value, maximum value, and step size. For the source, minimum and maximum values for the x and y coordinate are also specified; points that fall outside those bounds are not copied.
The number of z sections, wavelengths, and time points in the source region must either match the respective value for the destination region or must be one (in which case it is replicated to fill the destination region). As an example, if the source region is as follows:
and the destination region is
all the points in the first z section of the first wavelength and time point will be copied to the second through sixteenth sections in that wavelength and time point.
As another example, if the source region is
and a destination region defined as
the points that fall in the first section of the first wave will be copied to sections two through sixteen of the first wave, the points that fall in the first section of the second wave will be copied to sections two through sixteen of the second wave, and so on.
The copy operation does not check if it generates points at the same locations. The copy operation does preserve the ordering of points in a list (i.e. each destination list generated will contain the points, in order, which fall within the x, y, and z bounds for the source region from a single source list).
Occasionally, it is useful to generate points on a rectangular grid (for instance, if you use FixBadPixel to correct for bad lines in an image). Pressing the Grid... button opens a dialog where you enter the parameters for a grid of points and have them added to the current list when the Generate button in the dialog is pressed. If the number of points would overflow the current list, new lists are created as necessary. No checking is done to see if the points on the grid have the same coordinates as points already present in the list.
The following keys may be used while the mouse pointer is in the image window to change certain Pick Points parameters: