IPA::Global - methods that produce images where every pixel is a function of all pixels in the source image
Contains methods that produce images, where every pixel is a function of all pixels in the source image. The process can be described with the mapping function
s = M(R)
where s
is the pixel value in the output images, and R is the source image.
Closes edges of shapes on IMAGE, according to specified gradient
image. The unclosed shapes converted to the closed if the gradient spot between the suspected dents falls under maxlen
maximal length increment, mingradient
the minimal gradient value and the edge is longer than minedgelen
.
Supported types: Byte
Parameters:
Specifies the gradient image
Maximal edge length
Minimal edge length
Minimal gradient value
Fills closed shapes to eliminate the contours with holes in IMAGE.
Supported types: Byte
Parameters:
If true, the original image is changed
The edge breadth that is not touched by the algorithm
The pixel value used for determination whether a pixel belongs to the background.
The pixel value used for hole filling.
Must be either 4 or 8. Selects whether the algorithm must assume 4- or 8- pixel connection.
Identifies the objects on IMAGE and filters out these that have their area less than minArea
and more than maxArea
. The other parameters are identical to those passed to fill_holes.
Identifies the objects on IMAGE and returns the contours as array of anonymous arrays of 4- or 8- connected pixel coordinates.
The parameters are identical to those passed to fill_holes.
Supported types: Byte
See also IPA::Region.
Same as identify_contours
but returns a set of scan lines.
Returns coordinates of all pixels that match (if eq
is 1) or not match (eq
is 0) color match
.
Performs direct and inverse ( governed by inverse
boolean flag ) fast Fourier transform. IMAGE must have dimensions of power of 2. The resulted image is always of DComplex type.
Supported types: all
Performs direct and inverse ( governed by inverse
boolean flag ) fast Fourier transform. If IMAGE dimensions not of power of 2, then IMAGE is scaled up to the closest power of 2, and the result is scaled back to the original dimensions.
The resulted image is always of DComplex type.
Supported types: all
Performs band filtering of IMAGE in frequency domain. IMAGE must have dimensions of power of 2. The resulted image is always of DComplex type.
Supported types: all
Parameters:
Boolean flag, indicates whether the low-pass or the high-pass is to be performed.
Boolean flag, indicates if IMAGE must be treated as if it is in the spatial domain, and therefore conversion to the frequency domain must be performed first.
Boolean flag, indicates if the homomorph ( exponential ) equalization must be performed. Cannot be set to true if the image is in frequency domain ( if spatial
parameter set to true ).
Power operator applied to the input frequency.
Threshold value of the filter.
Multiplication factor used in homomorph equalization.
Performs band filtering of IMAGE in frequency domain. If IMAGE dimensions not of power of 2, then IMAGE is scaled up to the closest power of 2, and the result is scaled back to the original dimensions.
The resulted image is always of DComplex type.
Supported types: all
The parameters are same as those passed to band_filter.
Realizes Hough transform. If type is "line", linear transform is performed. With direct transform, resolution
is width of the resulted image.
Note: Returns a 8-bit grayscale image, which means that for all practical purposes the image shouldn't possibly contain more than 256 line candidates.
Supported types: all
Takes a Hough-transformed image, where each pixel is a line. For each non-zero pixel a line projection on a rectangle with given width and height is calculated. Returns array of quad values in format [x0,y0,x1,y2] where the coordinates stand for the start and the end of a line.
So, if the direct transform was called as
$h = hough( $i );
then plotting lines back (after $h was filtered) would be
$i-> line(@$_) for @{ hough2lines( $h, width => $i-> width, height => $i-> height ) };
Supported types: 8-bit (expects result from hough
function).
The following functions can draw lines on images, and are optimized for speed, because Prima doesn't support drawing on images outside begin_paint
/end_paint
scope.
Fill the given rectangular area with COLOR.
Draws set of horizontal lines as defined by LINES with COLOR. LINES is an array of triplet integers, where each contains [X1, X2, Y] coordinates - beginning of hline, end of hline, and vline.
Draws a single line from X1,Y1 to X2,Y2 .