highpass_imagehighpass_imageHighpassImageHighpassImagehighpass_image (算子名称)

名称

highpass_imagehighpass_imageHighpassImageHighpassImagehighpass_image — Extract high frequency components from an image.

参数签名

描述

highpass_imagehighpass_imageHighpassImageHighpassImageHighpassImagehighpass_image extracts high frequency components in an image by applying a linear filter with the following matrix (in case of a 7x5 matrix): 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -35 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 This corresponds to applying a mean operator (mean_imagemean_imageMeanImageMeanImageMeanImagemean_image), and then subtracting the original gray value. For byte images, a value of 128 is added to the result, i.e., zero crossings occur for 128. Correspondingly for uint2 images, 32767 is added.

This filter emphasizes high frequency components (edges and corners). The cutoff frequency is determined by the size (Height x Width) of the filter matrix: the larger the matrix, the smaller the cutoff frequency is.

At the image borders the pixels' gray values are mirrored. In case of over- or underflow the gray values are clipped (255 and 0, resp.).

注意

If even values are passed for HeightHeightHeightHeightheightheight or WidthWidthWidthWidthwidthwidth, 该算子 uses the next larger odd value instead. Thus, the center of the filter mask is always uniquely determined.

highpass_imagehighpass_imageHighpassImageHighpassImageHighpassImagehighpass_image can be executed on OpenCL devices. The same limitations as for mean_imagemean_imageMeanImageMeanImageMeanImagemean_image and sub_imagesub_imageSubImageSubImageSubImagesub_image apply.

Note that filter operators may return unexpected results if an image with a reduced domain is used as input. Please refer to the chapter 过滤器.

运行信息

• 支持OpenCL计算设备。
• 多线程类型:可重入(与非独占操作符并行运行)。
• 多线程作用域:全局(可以从任何线程调用)。
• 在元组级别自动并行化。
• 在图像通道级别自动并行化。
• Automatically parallelized on domain level.

参数表

例程 (C)

highpass_image(Image,&Highpass,7,5);
threshold(Highpass,&Region,60.0,255.0);
skeleton(Region,&Skeleton);

结果

highpass_imagehighpass_imageHighpassImageHighpassImageHighpassImagehighpass_image returns 2 ( H_MSG_TRUE) if all parameters are correct. If the input is empty the behavior can be set via set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>). If necessary, an exception is raised.

可能的后置算子

thresholdthresholdThresholdThresholdThresholdthreshold, skeletonskeletonSkeletonSkeletonSkeletonskeleton

可替代算子

mean_imagemean_imageMeanImageMeanImageMeanImagemean_image, sub_imagesub_imageSubImageSubImageSubImagesub_image, convol_imageconvol_imageConvolImageConvolImageConvolImageconvol_image, bandpass_imagebandpass_imageBandpassImageBandpassImageBandpassImagebandpass_image

参考其它

dyn_thresholddyn_thresholdDynThresholdDynThresholdDynThresholddyn_threshold

模块

Foundation

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