CImage:Class Description

CImage Class

The CImage class encapsulates functionality for working with images. Included in this huge class are tools for working with image files, doing image math operations, changing image geometry, making measurements, and working with header data. Additional methods for combining and merging images are found in the CImCombine class.

Executing Scripts from Image Windows

The Execute Script menu command may be used to open and execute a script directly from a Mira Image Window. When a script is executed from the Execute Script command, it is automatically sent a CImageView object named ParentImageView and a CImage object namedParentImage . The ParentImageView is a CImageView object that provides access to the CImageView CImageSet member and others. The ParentImage is a CImage object attached to the current image in the Image Window. You can use these names directly in the script or you can rename them, like V = ParentImageView and I = ParentImage. You can also get the individual CImage objects from the window's Image Set using CImageView:GetImage. A sample script call to be called from an Image Window is provided named Execute from Image Window test.lua.

Usage

Construction

Object = new_image()

Object = attachlist_image()

Object = CImage:new()

Object = CImage:AttachFromList()

Destruction

Object:delete()

Creation Functions	Non-class functions that create a new CImage object.
Construction and Destruction	Methods that create, copy, and delete CImage objects
Array Operations	Methods that work directly with image colums, rows, and regions, such as setting pixel values in a row or region.
Coordinates	Methods that work with pixel and world coordinates, distances, and measurements.
Filtering	Methods that perform filtering operations such as smoothing and enhancing.
General Methods	Methods that open files, create, save, and attach images.
Calibration	Methods that perform high level operations for calibrating CCD images.
Geometry	Methods that perform geometric operations such as scaling, rotating, expanding, etc.
Properties	Methods that retrieve image properties such as name, number of columns, exposure time, filter, image type, etc.
Keyword Operations	Methods that work with image headers and retrieve and set header keywords.
Math	Methods that perform mathematical operations between images and image values, including multiplication, exponentiation, etc.
Measurements	Methods that measure features in images including distance, angle, luminance, etc.
Math Operators	Syntax for using CImage objects as variables to simplify the syntax of complex operations, likeI2=I4+5.2 , or I2=I3*I4-17.14
Pixel Operations	Methods that work directly with image pixel values.

Creation - Non-class Functions

These functions are normally used to create and attach a new CImage object as an alternative to the class-based construction methods. A new CImage object is also returned by the GetImage method of the CImageView class.

attachlist_image	Creates a new CImage object attached to an image selected from an image window on the Mira desktop. This is equivalent to the AttachFromList class method.
new_image	Global function that creates a new CImage object.

Construction and Destruction - Class Methods

new	Creates a new instance of the CImage class. Various constructors are available.
delete	Deletes the instance of the CImage object and deletes its image from memory.
Copy	Copies the image to a new image.
AttachFromList	Creates a new CImage and attaches an image selected from the list of images in a CImageView.

General Methods

Close	Closes the image and deletes it from memory.
Create	Creates a new image of specified size and pixel type.
Display	Displays an image in a new image view window.
Open	Opens an image from a file.
Save	Saves the image to its file.
SaveAs	Saves the image to a new file name by prompting the user.
SaveTo	Saves the image to a new file name without prompting.
SaveUndo	Saves an "undo" copy of the image before making changes.
Undo	Restores the "undo" copy of the image.

Image Properties

Axes	Returns the number of image axes.
Bytes	Returns the number of bytes in the image pixel data.
Cols	Returns the number of image columns.
Darktime	Returns the dark integration time for the image.
Date	Returns the date the image was acquired, in days.
DateStr	Returns the date of image acquisition as a string.
DatatypeStr (obsolete)	Returns the image pixel type as a string. The name DatatypeStr is obsolete and should not be used going forward.
Datatype (obsolete)	Returns the image pixel type as a numeric index. The name Datatype is obsolete and should not be used going forward.
Exptime	Returns the image exposure time in seconds.
Filter	Returns the name of the filter used for image acquisition.
Gain	Returns the inverse gain in electrons per ADU.
ImageType	Returns the type of image, usually the value of the IMAGETYP keyword.
IsColor	Returns true if the image is a color pixel type.
IsInteger	Returns true if the image is an integer pixel type.
IsNumeric	Returns true if the image is a numeric pixel type.
IsReal	Returns true if the image is a real (floating point) pixel type.
Object	Returns the object description.
Path	Returns the image file path.
PixelBytes	Returns the number of bytes per pixel.
Pixels	Returns the number of pixels in the image.
PixelType	Returns the image pixel type as a numeric index.
PixelTypeStr	Returns the image pixel type as a string.
Rows	Returns the number of image rows.
Time	Returns the time of image acquisition as a number of seconds.
TimeStr	Returns the time of image acquisition as a string.

Measurements

Angle	Returns the angle formed by the line between 2 pixel coordinates.
AngleWcs	Returns the angle formed by the line between 2 world coordinates.
AreaUnits	Returns the world coordinate units for area measurements.
DistanceWcs	Returns the distance between 2 world coordinates.
Distance	Returns the distance between 2 pixel coordinates.
DistanceUnits	Returns the world coordinate units for distance measurements.
DistanceWcsStr	Returns as a string the distance between 2 world coordinates.

Coordinates

CoordUnits	Returns the coordinate units for an image axis.
GetAxisLabel	Returns the coordinate label for an image axis.
GetImageScale	Returns the image scale in world coordinates per pixel.
GetImageScaleXy	Returns the x and y axis image scale of the x and y axis in world coordinates per pixel.
PtInside	Returns true if a pixel coordinate is inside the image.
GetWcsProj	Returns an integer code for the world coordinate system ("WCS") projection used by the image.
GetWcsType	Returns an integer code for the type of world coordinate system ("WCS") calibration used by the image.
WcsIsEq	Returns true if the image has an equatorial world coordinate calibration.
WcsToXy	Returns the pixel coordinates for world coordinates specified in decimal degrees.
WcsStrToXy	Returns the pixel coordinates for world coordinates specified as strings in units of "HH:MM:SS.SSS" and "-DD:MM:SS.SSS".
XyToWcs	Returns the world coordinate in degrees for pixel coordinates.
XyToWcsStr	Returns the world coordinate as strings in units of "HH:MM:SS.SSS" and "-DD:MM:SS.SSS" for pixel coordinates.

Pixel Operations

PixGE	Returns the coordinate of the first pixel with value >= target value.
PixGELE	Returns the coordinate of the first pixel with value >= value or <= value 2.
GetVal	Returns the pixel value at a pixel coordinate in the form of a number.
GetValStr	Returns the image value at a pixel coordinate in the form of a string.
SetVal	Sets the pixel value at a pixel coordinate.
SetRegionVal	Sets the pixels inside a rectangular region to a specified value andnoise.
SetRegionValExclude	Sets the pixels outside a rectangular region to a specified value and noise.

Array Operations

ColToTable	Returns the data from an image column as a 1-dimensional array.
RowToTable	Returns the data from an image row as a 1-dimensional array.
RectToTable	Returns the data from an image rectangle as a 1-dimensional array.
ToTable	Returns the image data as a 1-dimensional array.
TableToCol	Replaces an image column with values in a 1-d 1-dimensional array.
TableToRow	Replaces an image row with values in a 1-d 1-dimensional array.
TableToRect	Replaces a rectangular image region with values in a 2-d 1-dimensional array.
ExtractByte	Extracts an image consisting of a specific byte plane.
ExtractChan	Creates an image consisting of a color channel from an RGB image.

Math Operations

Abs	Computes the absolute value of the image pixels.
Add	Adds an operand image.
AddNoise	Adds Gaussian random noise to a region.
Addx	Adds a numeric value.
Blend	Blends the values of the image with an operand image.
Blendx	Blends the image values with a numeric value.
Byteswap	Swaps the byte order of the pixels.
Chs	Changes the sign of the image values.
Div	Divides by an operand image.
Divx	Divides by a numeric value.
Exp	Raises base e to powers specified by the image pixels.
ExtractByte	Extracts an image consisting of a specific byte plane.
Log	Computes the base-e logarithm of the pixel values.
Log10	Computes the base-10 logarithm of the pixel values.
Mod	Calculates the remainder of division by an operand image.
Modx	Computes the remainder of division by a numeric value.
Mul	Multiplies by an operand image.
Mulx	Multiplies by a numeric value.
PixGE	Returns the coordinate of the first pixel with value >= target value.
PixGELE	Returns the coordinate of the first pixel with value >= value or <= value 2.
PolyFitSub	Fits and subtracts a polynomial from the image.
PolyFitDiv	Fits and divides a polynomial into the image.
PolyFitImage	Fit a polynomial and evaluate it in the image.
Pow	Raises the image values to a power.
Powa	Raises a base value to powers specified by the image pixels.
Powab	Raises the image pixels to the power defined by the pixels of an operand image.
Recip	Computes the reciprocal of the pixel values.
ExtractChan	Creates an image consisting of a color channel from an RGB image.
ScaleLinVal	Applies a linear scaling to the pixel values.
ScalePolyVal	Applies a polynomial intensity correction.
SetPixelType	Changes the image Pixel Type.
Sqrt	Computes the square root of the image values.
Sub	Subtracts an operand image.
Subx	Subtracts a numeric value.
Xdiv	Divides the image values into a numeric value.
Xsub	Subtracts the image values from a numeric value.

Image Geometry

Affine	Applies an affine transformation of shift, scale, and rotation.
BlockAvg	Averages pixel values into m x n super-pixels.
BlockSum	Sums pixel values into m x n super-pixels.
Crop	Crops a smaller piece from the image.
DimEq	Tests whether 2 images have the same dimensions.
Expand	Expands the image into a larger canvas with specified border value and optional random noise.
Hflip	Flips the image horizontally.
Imbed	Imbed the image at a specific location in another image.
Reorient	Reorients the image in various quadrant transformations.
Rot180	Rotates the image 180 degrees.
Rot270	Rotates the image 270 degrees.
Rot90	Rotates the image 90 degrees.
Rotate	Rotates the image by an angle about its center.
RotatePt	Rotates the image by an angle about a point.
Scale	Scales the image by a magnification factor.
ScaleXy	Scales the image independently by magnification factors in the x and y directions.
Shift	Shifts the image horizontally and vertically.
Transpose	Flips the image about its main diagonal.
Vflip	Flips the image vertically.

Header Keyword Operations

KwdDelete	Deletes a keyword from the image header.
KwdExists	Returns true if the named keyword exists in the image header.
KwdGetDMS	Returns a properly formatted angle string for a keyword value given in degrees, minutes, and seconds. Use this for keywords not in the standard format using : as a field delimiter.
KwdGetDmsEx	Returns a DMS angle for a string keyword plus a boolean flag indicating that the keyword is in the image header.
KwdGetHMS	Returns a MHS time string for a string keyword value given in hours, minutes, and seconds. Use this for keywords not in the standard format using : as a field delimiter.
KwdGetHmsEx	Returns an HMS time for a string keyword plus a boolean flag indicating that the keyword is in the image header.
KwdGetNum	Returns a numeric value keyword.
KwdGetNumEx	Returns a numeric value keyword plus a boolean flag indicating that the keyword is in the image header.
KwdGetSect	Returns the 4 column and row limits stored in a region section keyword, like BIASSEC.
KwdGetSectEx	Returns the 4 column and row limits stored in a region section keyword (e.g., BIASSEC), plus a boolean flag indicating that the keyword is in the image header.
KwdGetStr	Returns a string value keyword.
KwdGetStrEx	Returns a string value keyword plus a boolean flag indicating that the keyword is in the image header.
KwdGetVal	Returns the value of a keyword in any format (string, number, etc.) as a string.
KwdGetValEx	Returns the value of a keyword in any format (string, number, etc.) as a string and also a boolean flag indicating that the keyword is in the header.
KwdSetBlank	Adds a blank keyword to the image header.
KwdSetBlankStr	Adds a blank keyword with string value to the image header.
KwdSetBool	Sets the value of a boolean T/F keyword or adds the keyword to the image header.
KwdSetComment	Adds a comment keyword to the image header.
KwdSetDate	Sets the value of a date keyword or adds the keyword to the image header.
KwdSetHistory	Adds a history keyword to the image header.
KwdSetNum	Sets the value of a numeric keyword or adds the keyword to the image header.
KwdSetSect	Sets a region section keyword (e.g., BIASSEC) using the 4 column and row limits passed as numbers
KwdSetStr	Sets the value of a string keyword or adds the keyword to the image header.
KwdSetTime	Sets the value of a time keyword or adds the keyword to the image header.
KwdSetVal	Sets the value of a keyword or adds the keyword to the image header.

Image Calibration

ApplyPixelMask	Applies a pixel mask to repair image blemishes.
CreatePixelMask	Creates a mask file for pixels above or below threshold values.
CreatePixelMaskHigh	Creates a mask file for pixels above a threshold value.
CreatePixelMaskLow	Creates a mask file for pixels below a threshold value.
SetMaskedValue	Sets pixel values at coordinates identified in a pixel mask.
SubBiasFrame	Subtract a bias frame from the image.
SubBiasVal	Subtract a bias value from the image.
SubBiasRef	Subtract a reference bias value stored in a header keyword.
SubBiasCol	Compute and apply a column bias correction.
SubBiasRow	Compute and apply a row bias correction.
SubDarkFrame	Subtracts a dark frame from the image.
SubDarkScaled	Subtracts a time-scaled dark frame from the image.
SubDarkOpt	Subtracts a statistically optimized dark frame from the image.
DivFlatFrame	Divides the image by a flat field frame.
DivFlatNorm	Divides the image by a flat field frame while normalizing the flat during the calculation.

Filtering Methods

FiltBinomial	Smooths the image using a binomial weight rectangular kernel.
FiltBlockAvg	Block averages pixels in m x n rectangle groups, similar to binning a digital detector.
FiltBlockSum	Block sums pixels in m x n rectangle groups, similar to binning a digital detector.
FiltClipHigh	Replaces pixel values above a threshold value.
FiltClipLow	Replaces pixel values below a threshold value.
FiltEllips	Smooths the image using an equal weight elliptical kernel.
FiltGaussian	Smooths the image using a Gaussian weight elliptical kernel.
FiltGradient	Applies a directional derivative gradient filter.
FiltKernel	Applies a user-defined kernel.
FiltLaplacian	Applies a Laplacian filter, usually for edge detection.
FiltLine	Applies a directional line selection kernel.
FiltMax	Applies a maximum value filter.
FiltMedian	Applies a median filter.
FiltMin	Applies a minimum value filter.
FiltPrewitt	Applies a Prewitt directional gradient mask.
FiltRank	Applies a rank value filter.
FiltRect	Smooths the image using an equal weight rectangular kernel.
FiltRotGrad	Applies a rotational gradient filter to enhance rotational or "spoked" features.
FiltSharpen	Sharpens the image using a crispening filter.
FiltSobel	Applies a Sobel edge filter.
FiltUnsharpMask	Sharpens the image using unsharp masking.