如何更改CIDetector方向？

Question

所以我试图CIDetector在Swift中使用文本检测器.当我将手机指向一段文字时,它没有检测到它.但是,如果我将手机转到一边,它可以正常工作并检测到文本.如何更改它以便以正确的相机方向检测文本？这是我的代码:

准备文本检测功能:

func prepareTextDetector() -> CIDetector {
    let options: [String: AnyObject] = [CIDetectorAccuracy: CIDetectorAccuracyHigh, CIDetectorAspectRatio: 1.0]
    return CIDetector(ofType: CIDetectorTypeText, context: nil, options: options)
}

文字检测功能:

func performTextDetection(image: CIImage) -> CIImage? {
    if let detector = detector {
        // Get the detections
        let features = detector.featuresInImage(image)
        for feature in features as! [CITextFeature] {
            resultImage = drawHighlightOverlayForPoints(image, topLeft: feature.topLeft, topRight: feature.topRight,
                                                        bottomLeft: feature.bottomLeft, bottomRight: feature.bottomRight)                
            imagex = cropBusinessCardForPoints(resultImage!, topLeft: feature.topLeft, topRight: feature.topRight, bottomLeft: feature.bottomLeft, bottomRight: feature.bottomRight)
        }
    }
    return resultImage
}

它的定向方式与左侧相同,但不适用于正确的方向:

Answer 1

CIDetectorImageOrientation正如Apple在其CITextFeature文档中所述,你必须使用它:

[...]使用该CIDetectorImageOrientation选项指定查找直立文本的所需方向.

例如,您需要这样做

let features = detector.featuresInImage(image, options: [CIDetectorImageOrientation : 1]) 

1exif数字在哪里,取决于方向,可以计算如下

func imageOrientationToExif(image: UIImage) -> uint {
    switch image.imageOrientation {
    case UIImageOrientation.Up:
        return 1;
    case UIImageOrientation.Down:
        return 3;
    case UIImageOrientation.Left:
        return 8;
    case UIImageOrientation.Right:
        return 6;
    case UIImageOrientation.UpMirrored:
        return 2;
    case UIImageOrientation.DownMirrored:
        return 4;
    case UIImageOrientation.LeftMirrored:
        return 5;
    case UIImageOrientation.RightMirrored:
        return 7;
    }
}