如何使用iPhone在照片中找到矩形？

OpenCV2.2\\samples\\cpp\\squares.cpp

findContours

approxPolyDP

CIImage *image = // your image
NSDictionary *options = @{CIDetectorAccuracy: CIDetectorAccuracyHigh, CIDetectorAspectRatio: @(1.0)};
CIDetector *rectangleDetector = [CIDetector detectorOfType:CIDetectorTypeRectangle context:nil options:options];

NSArray *rectangleFeatures = [rectangleDetector featuresInImage:image];

for (CIRectangleFeature *rectangleFeature in rectangleFeatures) {
    CGPoint topLeft = rectangleFeature.topLeft;
    CGPoint topRight = rectangleFeature.topRight;
    CGPoint bottomLeft = rectangleFeature.bottomLeft;
    CGPoint bottomRight = rectangleFeature.bottomRight;
}

cv::Canny

cv::cornerHarris

cv::HoughLines

goodFeaturesToTrack()

CornerHarris()