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196 <h1>Module effect Methods</h1>
197 <p class="navigation-index">[<a href="#AdaptiveBlurImage">AdaptiveBlurImage</a> • <a href="#AdaptiveSharpenImage">AdaptiveSharpenImage</a> • <a href="#BlurImage">BlurImage</a> • <a href="#ConvolveImage">ConvolveImage</a> • <a href="#DespeckleImage">DespeckleImage</a> • <a href="#EdgeImage">EdgeImage</a> • <a href="#EmbossImage">EmbossImage</a> • <a href="#FilterImage">FilterImage</a> • <a href="#GaussianBlurImage">GaussianBlurImage</a> • <a href="#MedianFilterImage">MedianFilterImage</a> • <a href="#MotionBlurImage">MotionBlurImage</a> • <a href="#PreviewImage">PreviewImage</a> • <a href="#RadialBlurImage">RadialBlurImage</a> • <a href="#ReduceNoiseImage">ReduceNoiseImage</a> • <a href="#SelectiveBlurImage">SelectiveBlurImage</a> • <a href="#ShadeImage">ShadeImage</a> • <a href="#SharpenImage">SharpenImage</a> • <a href="#SpreadImage">SpreadImage</a> • <a href="#UnsharpMaskImage">UnsharpMaskImage</a>]</p>
199 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="AdaptiveBlurImage">AdaptiveBlurImage</a></h2>
200 <div class="doc-section">
202 <p>AdaptiveBlurImage() adaptively blurs the image by blurring less intensely near image edges and more intensely far from edges. We blur the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and AdaptiveBlurImage() selects a suitable radius for you.</p>
204 <p>The format of the AdaptiveBlurImage method is:</p>
207 Image *AdaptiveBlurImage(const Image *image,const double radius,
208 const double sigma,ExceptionInfo *exception)
209 Image *AdaptiveBlurImageChannel(const Image *image,
210 const ChannelType channel,double radius,const double sigma,
211 ExceptionInfo *exception)
214 <p>A description of each parameter follows:</p>
220 <p>the channel type.</p>
223 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
226 <p>the standard deviation of the Laplacian, in pixels.</p>
229 <p>return any errors or warnings in this structure.</p>
232 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="AdaptiveSharpenImage">AdaptiveSharpenImage</a></h2>
233 <div class="doc-section">
235 <p>AdaptiveSharpenImage() adaptively sharpens the image by sharpening more intensely near image edges and less intensely far from edges. We sharpen the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and AdaptiveSharpenImage() selects a suitable radius for you.</p>
237 <p>The format of the AdaptiveSharpenImage method is:</p>
240 Image *AdaptiveSharpenImage(const Image *image,const double radius,
241 const double sigma,ExceptionInfo *exception)
242 Image *AdaptiveSharpenImageChannel(const Image *image,
243 const ChannelType channel,double radius,const double sigma,
244 ExceptionInfo *exception)
247 <p>A description of each parameter follows:</p>
253 <p>the channel type.</p>
256 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
259 <p>the standard deviation of the Laplacian, in pixels.</p>
262 <p>return any errors or warnings in this structure.</p>
265 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="BlurImage">BlurImage</a></h2>
266 <div class="doc-section">
268 <p>BlurImage() blurs an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, the radius should be larger than sigma. Use a radius of 0 and BlurImage() selects a suitable radius for you.</p>
270 <p>BlurImage() differs from GaussianBlurImage() in that it uses a separable kernel which is faster but mathematically equivalent to the non-separable kernel.</p>
272 <p>The format of the BlurImage method is:</p>
275 Image *BlurImage(const Image *image,const double radius,
276 const double sigma,ExceptionInfo *exception)
277 Image *BlurImageChannel(const Image *image,const ChannelType channel,
278 const double radius,const double sigma,ExceptionInfo *exception)
281 <p>A description of each parameter follows:</p>
287 <p>the channel type.</p>
290 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
293 <p>the standard deviation of the Gaussian, in pixels.</p>
296 <p>return any errors or warnings in this structure.</p>
299 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="ConvolveImage">ConvolveImage</a></h2>
300 <div class="doc-section">
302 <p>ConvolveImage() applies a custom convolution kernel to the image.</p>
304 <p>The format of the ConvolveImage method is:</p>
307 Image *ConvolveImage(const Image *image,const size_t order,
308 const double *kernel,ExceptionInfo *exception)
309 Image *ConvolveImageChannel(const Image *image,const ChannelType channel,
310 const size_t order,const double *kernel,ExceptionInfo *exception)
313 <p>A description of each parameter follows:</p>
319 <p>the channel type.</p>
322 <p>the number of columns and rows in the filter kernel.</p>
325 <p>An array of double representing the convolution kernel.</p>
328 <p>return any errors or warnings in this structure.</p>
331 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="DespeckleImage">DespeckleImage</a></h2>
332 <div class="doc-section">
334 <p>DespeckleImage() reduces the speckle noise in an image while perserving the edges of the original image.</p>
336 <p>The format of the DespeckleImage method is:</p>
339 Image *DespeckleImage(const Image *image,ExceptionInfo *exception)
342 <p>A description of each parameter follows:</p>
348 <p>return any errors or warnings in this structure.</p>
351 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="EdgeImage">EdgeImage</a></h2>
352 <div class="doc-section">
354 <p>EdgeImage() finds edges in an image. Radius defines the radius of the convolution filter. Use a radius of 0 and EdgeImage() selects a suitable radius for you.</p>
356 <p>The format of the EdgeImage method is:</p>
359 Image *EdgeImage(const Image *image,const double radius,
360 ExceptionInfo *exception)
363 <p>A description of each parameter follows:</p>
369 <p>the radius of the pixel neighborhood.</p>
372 <p>return any errors or warnings in this structure.</p>
375 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="EmbossImage">EmbossImage</a></h2>
376 <div class="doc-section">
378 <p>EmbossImage() returns a grayscale image with a three-dimensional effect. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and Emboss() selects a suitable radius for you.</p>
380 <p>The format of the EmbossImage method is:</p>
383 Image *EmbossImage(const Image *image,const double radius,
384 const double sigma,ExceptionInfo *exception)
387 <p>A description of each parameter follows:</p>
393 <p>the radius of the pixel neighborhood.</p>
396 <p>the standard deviation of the Gaussian, in pixels.</p>
399 <p>return any errors or warnings in this structure.</p>
402 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="FilterImage">FilterImage</a></h2>
403 <div class="doc-section">
405 <p>FilterImage() applies a custom convolution kernel to the image.</p>
407 <p>The format of the FilterImage method is:</p>
410 Image *FilterImage(const Image *image,const KernelInfo *kernel,
411 ExceptionInfo *exception)
412 Image *FilterImageChannel(const Image *image,const ChannelType channel,
413 const KernelInfo *kernel,ExceptionInfo *exception)
416 <p>A description of each parameter follows:</p>
422 <p>the channel type.</p>
425 <p>the filtering kernel.</p>
428 <p>return any errors or warnings in this structure.</p>
431 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="GaussianBlurImage">GaussianBlurImage</a></h2>
432 <div class="doc-section">
434 <p>GaussianBlurImage() blurs an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, the radius should be larger than sigma. Use a radius of 0 and GaussianBlurImage() selects a suitable radius for you</p>
436 <p>The format of the GaussianBlurImage method is:</p>
439 Image *GaussianBlurImage(const Image *image,onst double radius,
440 const double sigma,ExceptionInfo *exception)
441 Image *GaussianBlurImageChannel(const Image *image,
442 const ChannelType channel,const double radius,const double sigma,
443 ExceptionInfo *exception)
446 <p>A description of each parameter follows:</p>
452 <p>the channel type.</p>
455 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
458 <p>the standard deviation of the Gaussian, in pixels.</p>
461 <p>return any errors or warnings in this structure.</p>
464 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="MedianFilterImage">MedianFilterImage</a></h2>
465 <div class="doc-section">
467 <p>MedianFilterImage() applies a digital filter that improves the quality of a noisy image. Each pixel is replaced by the median in a set of neighboring pixels as defined by radius.</p>
469 <p>The algorithm was contributed by Mike Edmonds and implements an insertion sort for selecting median color-channel values. For more on this algorithm see "Skip Lists: A probabilistic Alternative to Balanced Trees" by William Pugh in the June 1990 of Communications of the ACM.</p>
471 <p>The format of the MedianFilterImage method is:</p>
474 Image *MedianFilterImage(const Image *image,const double radius,
475 ExceptionInfo *exception)
478 <p>A description of each parameter follows:</p>
484 <p>the radius of the pixel neighborhood.</p>
487 <p>return any errors or warnings in this structure.</p>
490 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="MotionBlurImage">MotionBlurImage</a></h2>
491 <div class="doc-section">
493 <p>MotionBlurImage() simulates motion blur. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and MotionBlurImage() selects a suitable radius for you. Angle gives the angle of the blurring motion.</p>
495 <p>Andrew Protano contributed this effect.</p>
497 <p>The format of the MotionBlurImage method is:</p>
500 Image *MotionBlurImage(const Image *image,const double radius,
501 const double sigma,const double angle,ExceptionInfo *exception)
502 Image *MotionBlurImageChannel(const Image *image,const ChannelType channel,
503 const double radius,const double sigma,const double angle,
504 ExceptionInfo *exception)
507 <p>A description of each parameter follows:</p>
513 <p>the channel type.</p>
516 <p>the radius of the Gaussian, in pixels, not counting the center</p>
518 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
521 <p>the standard deviation of the Gaussian, in pixels.</p>
524 <p>Apply the effect along this angle.</p>
527 <p>return any errors or warnings in this structure.</p>
530 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="PreviewImage">PreviewImage</a></h2>
531 <div class="doc-section">
533 <p>PreviewImage() tiles 9 thumbnails of the specified image with an image processing operation applied with varying parameters. This may be helpful pin-pointing an appropriate parameter for a particular image processing operation.</p>
535 <p>The format of the PreviewImages method is:</p>
538 Image *PreviewImages(const Image *image,const PreviewType preview,
539 ExceptionInfo *exception)
542 <p>A description of each parameter follows:</p>
548 <p>the image processing operation.</p>
551 <p>return any errors or warnings in this structure.</p>
554 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="RadialBlurImage">RadialBlurImage</a></h2>
555 <div class="doc-section">
557 <p>RadialBlurImage() applies a radial blur to the image.</p>
559 <p>Andrew Protano contributed this effect.</p>
561 <p>The format of the RadialBlurImage method is:</p>
564 Image *RadialBlurImage(const Image *image,const double angle,
565 ExceptionInfo *exception)
566 Image *RadialBlurImageChannel(const Image *image,const ChannelType channel,
567 const double angle,ExceptionInfo *exception)
570 <p>A description of each parameter follows:</p>
576 <p>the channel type.</p>
579 <p>the angle of the radial blur.</p>
582 <p>return any errors or warnings in this structure.</p>
585 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="ReduceNoiseImage">ReduceNoiseImage</a></h2>
586 <div class="doc-section">
588 <p>ReduceNoiseImage() smooths the contours of an image while still preserving edge information. The algorithm works by replacing each pixel with its neighbor closest in value. A neighbor is defined by radius. Use a radius of 0 and ReduceNoise() selects a suitable radius for you.</p>
590 <p>The format of the ReduceNoiseImage method is:</p>
593 Image *ReduceNoiseImage(const Image *image,const double radius,
594 ExceptionInfo *exception)
597 <p>A description of each parameter follows:</p>
603 <p>the radius of the pixel neighborhood.</p>
606 <p>return any errors or warnings in this structure.</p>
609 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="SelectiveBlurImage">SelectiveBlurImage</a></h2>
610 <div class="doc-section">
612 <p>SelectiveBlurImage() selectively blur pixels within a contrast threshold. It is similar to the unsharpen mask that sharpens everything with contrast above a certain threshold.</p>
614 <p>The format of the SelectiveBlurImage method is:</p>
617 Image *SelectiveBlurImage(const Image *image,const double radius,
618 const double sigma,const double threshold,ExceptionInfo *exception)
619 Image *SelectiveBlurImageChannel(const Image *image,
620 const ChannelType channel,const double radius,const double sigma,
621 const double threshold,ExceptionInfo *exception)
624 <p>A description of each parameter follows:</p>
630 <p>the channel type.</p>
633 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
636 <p>the standard deviation of the Gaussian, in pixels.</p>
639 <p>only pixels within this contrast threshold are included in the blur operation.</p>
642 <p>return any errors or warnings in this structure.</p>
645 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="ShadeImage">ShadeImage</a></h2>
646 <div class="doc-section">
648 <p>ShadeImage() shines a distant light on an image to create a three-dimensional effect. You control the positioning of the light with azimuth and elevation; azimuth is measured in degrees off the x axis and elevation is measured in pixels above the Z axis.</p>
650 <p>The format of the ShadeImage method is:</p>
653 Image *ShadeImage(const Image *image,const MagickBooleanType gray,
654 const double azimuth,const double elevation,ExceptionInfo *exception)
657 <p>A description of each parameter follows:</p>
663 <p>A value other than zero shades the intensity of each pixel.</p>
665 <h5>azimuth, elevation</h5>
666 <p>Define the light source direction.</p>
669 <p>return any errors or warnings in this structure.</p>
672 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="SharpenImage">SharpenImage</a></h2>
673 <div class="doc-section">
675 <p>SharpenImage() sharpens the image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and SharpenImage() selects a suitable radius for you.</p>
677 <p>Using a separable kernel would be faster, but the negative weights cancel out on the corners of the kernel producing often undesirable ringing in the filtered result; this can be avoided by using a 2D gaussian shaped image sharpening kernel instead.</p>
679 <p>The format of the SharpenImage method is:</p>
682 Image *SharpenImage(const Image *image,const double radius,
683 const double sigma,ExceptionInfo *exception)
684 Image *SharpenImageChannel(const Image *image,const ChannelType channel,
685 const double radius,const double sigma,ExceptionInfo *exception)
688 <p>A description of each parameter follows:</p>
694 <p>the channel type.</p>
697 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
700 <p>the standard deviation of the Laplacian, in pixels.</p>
703 <p>return any errors or warnings in this structure.</p>
706 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="SpreadImage">SpreadImage</a></h2>
707 <div class="doc-section">
709 <p>SpreadImage() is a special effects method that randomly displaces each pixel in a block defined by the radius parameter.</p>
711 <p>The format of the SpreadImage method is:</p>
714 Image *SpreadImage(const Image *image,const double radius,
715 ExceptionInfo *exception)
718 <p>A description of each parameter follows:</p>
724 <p>Choose a random pixel in a neighborhood of this extent.</p>
727 <p>return any errors or warnings in this structure.</p>
730 <h2><a href="http://www.imagemagick.org/api/MagickCore/effect_8c.html" id="UnsharpMaskImage">UnsharpMaskImage</a></h2>
731 <div class="doc-section">
733 <p>UnsharpMaskImage() sharpens one or more image channels. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and UnsharpMaskImage() selects a suitable radius for you.</p>
735 <p>The format of the UnsharpMaskImage method is:</p>
738 Image *UnsharpMaskImage(const Image *image,const double radius,
739 const double sigma,const double amount,const double threshold,
740 ExceptionInfo *exception)
741 Image *UnsharpMaskImageChannel(const Image *image,
742 const ChannelType channel,const double radius,const double sigma,
743 const double amount,const double threshold,ExceptionInfo *exception)
746 <p>A description of each parameter follows:</p>
752 <p>the channel type.</p>
755 <p>the radius of the Gaussian, in pixels, not counting the center pixel.</p>
758 <p>the standard deviation of the Gaussian, in pixels.</p>
761 <p>the percentage of the difference between the original and the blur image that is added back into the original.</p>
764 <p>the threshold in pixels needed to apply the diffence amount.</p>
767 <p>return any errors or warnings in this structure.</p>
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