ios - 是否可以在 IOS swift 中从更大的图像中检测到矩形图像？

Question

例如，我在 table 上放了一张名片，我只想扫描出名片。类似于 QR 码扫描仪，我想将名片图像扫描到应用程序中。

我听说过 OpenCV，但不确定如何在 swift 3 中使用它。有什么建议可以指导我朝着正确的方向前进吗？

Answer 1

是的!使用 CoreImage 的 CIDetector 可以检测矩形。这是您很可能正在寻找的代码 (Swift 3)!

func performRectangleDetection(image: CIImage) -> CIImage? {
        var resultImage: CIImage?
        resultImage = image
        let detector = CIDetector(ofType: CIDetectorTypeRectangle, context: nil, options: [CIDetectorAccuracy: CIDetectorAccuracyHigh, CIDetectorAspectRatio: 1.6, CIDetectorMaxFeatureCount: 10] )!

        // Get the detections
        var halfPerimiterValue = 0.0 as Float;
        let features = detector.features(in: image)
        print("feature \(features.count)")
        for feature in features as! [CIRectangleFeature] {

            let p1 = feature.topLeft
            let p2 = feature.topRight
            let width = hypotf(Float(p1.x - p2.x), Float(p1.y - p2.y));
            //NSLog(@"xaxis    %@", @(p1.x));
            //NSLog(@"yaxis    %@", @(p1.y));
            let p3 = feature.topLeft
            let p4 = feature.bottomLeft
            let height = hypotf(Float(p3.x - p4.x), Float(p3.y - p4.y));
            let currentHalfPerimiterValue = height+width;
            if (halfPerimiterValue < currentHalfPerimiterValue)
            {
                halfPerimiterValue = currentHalfPerimiterValue
                resultImage = cropBusinessCardForPoints(image: image, topLeft: feature.topLeft, topRight: feature.topRight,
                                                        bottomLeft: feature.bottomLeft, bottomRight: feature.bottomRight)
                print("perimmeter   \(halfPerimiterValue)")
            }

        }

        return resultImage
    }

    func cropBusinessCardForPoints(image: CIImage, topLeft: CGPoint, topRight: CGPoint, bottomLeft: CGPoint, bottomRight: CGPoint) -> CIImage {

        var businessCard: CIImage
        businessCard = image.applyingFilter(
            "CIPerspectiveTransformWithExtent",
            withInputParameters: [
                "inputExtent": CIVector(cgRect: image.extent),
                "inputTopLeft": CIVector(cgPoint: topLeft),
                "inputTopRight": CIVector(cgPoint: topRight),
                "inputBottomLeft": CIVector(cgPoint: bottomLeft),
                "inputBottomRight": CIVector(cgPoint: bottomRight)])
        businessCard = image.cropping(to: businessCard.extent)

        return businessCard
    }

调用函数performRectangleDetection，这里cropBusinessCardForPoints是助手。

UIImage/CIImage Conversion .

祝你好运!

仅供引用:使用CoreML 是最佳选择之一。