[英]Dealing with RGB of the image
I am developing one application . 我正在开发一个应用程序。 I have requirement like my application should detect particular color of the image .
我有要求,例如我的应用程序应检测图像的特定颜色。 For eg if i want to detect the red color then i should see only the red areas of the image.
例如,如果我要检测红色,则应该只看到图像的红色区域。 I have tried this by following way :
我已经尝试通过以下方式:
psudocode : 伪码:
First i have got the information of the each pixel of the image in the form of RGB using: 首先,我使用以下方法以RGB的形式获取了图像的每个像素的信息:
for(int i=0; i < width; ++i)
{
for (int j=0; j <height; j++)
{
byteIndex = (bytesPerRow * j) + i * bytesPerPixel;
CGFloat red = (rawData[byteIndex] * 1.0) /255.0;
CGFloat green = (rawData[byteIndex + 1] * 1.0)/255.0 ;
CGFloat blue = (rawData[byteIndex + 2] * 1.0)/255.0 ;
if (red>0.9 && red<1)
{
rgba[byteIndex] =red*255;
rgba[byteIndex+1] =green*0 ;
rgba[byteIndex+2] = blue*0;
count++;
}
}
}
then i am assigning this information to another image with null blue and green section hence i can only see the red areas of the image .It is working fine . 然后我将此信息分配给另一个图像,该图像的蓝色和绿色部分为空,因此我只能看到该图像的红色区域。它工作正常。
But the problem is with the for loop. 但是问题出在for循环上。 I have to iterate for loop depend on the the height and width of the image .
我必须根据图像的高度和宽度迭代循环。 For eg .
例如。 If height of the image is 300 and width is 400 then is have to iterate the for loop for 300 * 400 =120000 times Which i don't think is a better way .So is there any way to do this efficiently ?
如果图像的高度是300而宽度是400,则必须迭代for循环300 * 400 = 120000次,我认为这不是更好的方法。那么有什么方法可以有效地做到这一点? is there any open source library to achieve this ?
有没有开源库可以实现这一目标?
You can begin optimizing your code. 您可以开始优化代码。 There are a lot of unnecessary operations and float/integer conversions there.
那里有很多不必要的操作和浮点/整数转换。
for ( NSUInteger i = 0; i < width * height ; i ++ ) {
NSUInteger red = rawData[i] ;
if ( red > 230 ) {
rawData[i+1] = 0 ;
rawData[i+2] = 0 ;
}
}
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