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?????????????????????????????????????Objective-C?????????????????????????????????????????Objective-C?????????
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[ G(x, y) = \frac{1}{\sigma \sqrt{2\pi}} e^{-\frac{(x - x_0)^2 + (y - y_0)^2}{2\sigma^2}} ]???((x_0, y_0))????????(\sigma)??????????????????????????????????????????????
?Objective-C????????????????????
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????????????????????????????????????????Objective-C???????????????
???????????????????????Objective-C?????????????
#import@interface GaussianFilter : NSObject- (NSArray *)applyFilterToImage:(NSData *)imageData;@end
#import#include // ??????Accelerate??@interface GaussianFilter : NSObject- (NSData *)filterImageData:(NSData *)data;@end@implementation GaussianFilter- (NSData *)filterImageData:(NSData *)data { // ??????? double sigma = 1.0; // ???????? int filterSize = (int)(sigma * 2.0 * sqrt(2)); // ????? int halfSize = filterSize / 2; // ???????? double *filter = calloc(filterSize, sizeof(double)); for (int i = 0; i < filterSize; i++) { for (int j = 0; j < filterSize; j++) { int dx = abs(i - halfSize); int dy = abs(j - halfSize); filter[i * filterSize + j] = exp(-sigma * sigma * (dx * dx + dy * dy) / 2); } } // ?????? NSImage *image = (NSImage *)[UIImage dataWithData:data]; NSImage *resultImage = [[UIImage alloc] init]; // ????? NSData *grayData = [image dataWithMappingOption: NSImageMappingGray]; // ????? unsigned char *grayBuffer = (unsigned char *)grayData.data; unsigned char *resultBuffer = (unsigned char *)[resultImage dataWithMappingOption: NSImageMappingGray]; for (int y = 0; y < image.height; y++) { for (int x = 0; x < image.width; x++) { // ???????? double sum = 0.0; for (int fi = 0; fi < filterSize; fi++) { for (int fj = 0; fj < filterSize; fj++) { int srcX = x + fi - halfSize; int srcY = y + fj - halfSize; if (srcX >= 0 && srcX < image.width && srcY >= 0 && srcY < image.height) { sum += grayBuffer[srcY * image.width + srcX] * filter[fi * filterSize + fj]; } } } // ?????? unsigned char *newPixel = (unsigned char *)&resultBuffer[y * resultImage.width + x]; newPixel = (unsigned char)((sum / filterSize) * 255); // ????????????? resultBuffer[y * resultImage.width + x] = newPixel; } } return [resultImage dataWithMappingOption: NSImageMappingGray];}@end
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???????????????(\sigma)?????????????(\sigma)????????????????(\sigma)????????????
?????????????????????????????????????????????Accelerate???????????????????
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???????????????Objective-C??????????????????????????????????????????????????????????????????????????????
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