使用ios查找圖形的峯值

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我必須在ios上找到ECG波形的峯值，因此我首先應用了顏色檢測代碼來檢測黑色波形，然後通過ios找到了該像素的座標使用ios查找圖形的峯值

CGImageRef imgSource = self.ImageView.image.CGImage; 
CFDataRef m_DataRed1 = CGDataProviderCopyData(CGImageGetDataProvider(imgSource)); 
CGFloat myheight; 
CGFloat mywidth; 
myheight= CGImageGetHeight(imgSource); 
mywidth = CGImageGetWidth(imgSource); 
UInt8 *dataOrignal = (UInt8 *)CFDataGetBytePtr(m_DataRed1); 
double lenghtSource = CFDataGetLength(m_DataRed1); 
NSLog(@"lenght : %f",lenghtSource); 

int bytesPerPixel_ = CGImageGetBitsPerPixel(imgSource)/8; 
size_t bytesPerRow = CGImageGetBytesPerRow(imgSource); 
NSLog(@"height = %f, width = %f, bytesperPixel = %d",myheight,mywidth,bytesPerPixel_); 
for(int x = 0; x < mywidth; x++) 
{ 
    for(int y = 0; y < myheight; y++) 
    { 
     int pixelStartIndex = 4*((bytesPerRow*x)+y); 
     if (pixelStartIndex <= lenghtSource) { 
      UInt8 alphaVal = dataOrignal[pixelStartIndex]; 
      UInt8 redVal = dataOrignal[pixelStartIndex + 1]; 
      UInt8 greenVal = dataOrignal[pixelStartIndex + 2]; 
      UInt8 blueVal = dataOrignal[pixelStartIndex + 3]; 

      if(redVal == 236 || blueVal == 236 || greenVal == 236) 
      { 
       dataOrignal[pixelStartIndex + 1] = 205; 
       dataOrignal[pixelStartIndex +2] = 25; 
       dataOrignal[pixelStartIndex+3]= 55; 
       NSLog(@"x %d, y = %d, index = %d", x, y,pixelStartIndex); 
      } 

     } 
    }

}

NSUInteger width = CGImageGetWidth(imgSource); //202 
NSUInteger height = CGImageGetHeight(imgSource);//173 
size_t bitsPerComponent = CGImageGetBitsPerComponent(imgSource); 
size_t bitsPerPixel = CGImageGetBitsPerPixel(imgSource); 




NSLog(@"the width = %u and height=%u of the image is ",width,height); 
NSLog(@"the bits per component is %zd", bitsPerComponent); 
NSLog(@"the bits per pixel is %zd", bitsPerPixel); 
NSLog(@"the bytes per row is %zd" , bytesPerRow); 

CGColorSpaceRef colorspace = CGImageGetColorSpace(imgSource); 
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imgSource); 
CFDataRef newData = CFDataCreate(NULL, dataOrignal, lenghtSource); 
CGDataProviderRef provider = CGDataProviderCreateWithCFData(newData); 

CGContextRef context = CGBitmapContextCreate(newData, width, height, bitsPerComponent, bytesPerRow, colorspace, bitmapInfo); 
CGPoint point = CGContextGetTextPosition(context); 
NSInteger xx = point.x;

// point.y;

NSLog(@"this is the value of x axis %d",xx); 

CGImageRef newImg = CGImageCreate(width, height, bitsPerComponent, bitsPerPixel, bytesPerRow, colorspace, bitmapInfo, provider, NULL, true, kCGRenderingIntentDefault); 





UIImage *newImage1 = [UIImage imageWithCGImage:newImg]; 
self.ImageView.image = newImage1;

現在我想找到峯值的x和y值，所以任何人都可以幫助我，我怎麼能找到它？

來源

2013-05-06 Waleed Ahmed

首先定義你想要治療的高峯。

如果一個簡單的局部極大值，然後在相鄰索引中搜索值序列a，b，c，其中一個< b> c。儘管它們可以很容易地檢測到充滿峯值的靜止段，但它們甚至允許相等。

可能是一種更好的方法在平滑曲線上執行此搜索。

來源

2013-05-06 22:14:57 jmihalicza

感謝您的回覆，您可以查看此圖片http://www.google.com.pk/imgres?imgurl=http://www.cvphysiology.com/Arrhythmias/ECG%2520trace%2520with%2520grid.gif&imgrefurl=http ：//www.cvphysiology.com/Arrhythmias/A009.htm&h=317&w=350&sz=14&tbnid=RVV0Aj8MifiGoM：＆TBNH = 91＆tbnw = 100＆變焦= 1＆USG = __ ytoheH7aeVESI41K3pCezUBpOjI =＆的docID = e7Ao78HjT4zcMM＆SA = X＆EI = sCuIUdy_HaLw4QSU3ICIBw＆VED = 0CDUQ9QEwAQ＆從該圖像DUR = 256 你可以知道我想要得到的結果 – 2013-05-06 22:16:37

另一種方法是以積極和消極部分的形式在一階導數中搜索峯值。你可以微調你想接受的陡峭峯值。 – jmihalicza 2013-05-06 22:21:24

是的，我知道但實際上我沒有找到如何編碼和添加上面的代碼，你可以請爲我做嗎？我會對你很好：| – 2013-05-06 22:24:49

使用ios查找圖形的峯值

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