Peking University

Founder Mobile Media Technology (beijing) Co., Ltd.

Wanyi Che

Zhenhua Liu

Ling Zhang

Chao Guan

Gezhang Liu

Method and system for detecting a correction pattern in a QR code are disclosed. In the detection of a correction pattern, coordinates of the correction pattern is at first roughly estimated according to the detected coordinates of the detection patterns and different QR code versions, then a square region is specified around the coordinates of the correction pattern, in which a search is performed repeatedly. Finally, in conjunction with the characteristic of the correction pattern itself, i.e., having a line segment meeting a predetermined ratio, the correction pattern may be accurately located in the predetermined area, without the need of searching patterns meeting a 1:1:1 ratio line by line in the entire QR code image.

Method and system for detecting a correction pattern in a QR code

Binarization method and system for two dimensional code images is provided. Each block region has a different grayscale threshold. Thus, for each block region, whether a pixel in the block region is determined as black or white restoring process is not solely based on the grayscale value of the pixel itself, but also an average grayscale value of a predetermined area specified for a block region where the pixel locates. That is to say, when the predetermined area in which the block region locates has generally a larger grayscale value, the grayscale threshold corresponding to the block region may become larger, and vice versa. Because the grayscale threshold of a block region is closely related to grayscale values in a background of this block region, external circumstance interference may be prevented from an obtained binary result, producing a clear binary image accordingly.

Method and system for binarization of two dimensional code image

Method and system for detecting detection patterns of a QR code is disclosed, detection is performed in a first direction and then in a second direction based on the first direction detection to detect a line segment having a length ratio of black:white:black:white:black meeting a predetermined ratio to determine the central points of the detection patterns, and thereby find out all detection patterns. Line-by-line traversal detection in a first direction is used to detect the detection patterns. Detection is performed based on the detected central point of the first line segment. Thus, detection steps may be greatly saved to simplify the detection procedure and improve computing speed. Fast detection of detection patterns may be realized for a QR code image.

Method and system for detecting detection patterns of QR code

Method and system for decoding a two dimensional code is disclosed. In the binarization process of a two dimensional code image, through performing a dividing operation on the two dimensional code image, each block region has a different grayscale threshold. For each block region, whether a pixel in the block region is determined as black or white is not solely based on the grayscale value of the pixel itself, but also an average grayscale value of a predetermined area set for the block region where the pixel locates. When the predetermined area in which the block region locates has a larger grayscale value as a whole, the grayscale threshold corresponding to the block region may become larger, and vice versa.

System for decoding two dimensional code and method thereof

A method and system for filtering detection patterns in a QR code is provided in this invention. When multiple detection patterns get into a QR code image due to interference or other reasons, first of all, an side length is determined for each pattern to be detected, and then an average value of the side lengths of multiple patterns to be detected is determined, after which through comparing with a predetermined reference value, patterns to be detected meeting a predetermined condition are determined as detection patterns. An effective solution is provided to fill the gap in the prior art of unable to remove detection patterns caused by interference appropriately when more than three detection patterns are found.

Method and system for filtering detection patterns in a QR code

Method and system for determining QR code binary image is provided. Locating lines on which edges of the QR code locate are determined according to location information of locating points within the QR code image and distances between the locating points to edges of the QR code. Distances may be used to obtain locating lines on which edges of the QR code locate, with relatively smaller errors. When a QR code image is distorted, it generally bulges outward. The position of a determined locating line is within the interior of the QR code image, and an actual edge of the QR code partly overlaps with the locating line and partly locate on external side of locating line. Edge points on external side of a locating line are detected along the direction of the locating line and then are connected to form an edge line of QR code.

Method and system for determining edge line in QR code binary image

Method and system for correcting a QR code image is provided. An initial coordination system and a correction coordination system are determined at first. Conversion coefficients are obtained according to the coordinates of the central point of each detection pattern, the coordinates of the locating point in the initial coordinate system, the correction coordinate system. For each point in the correction coordinate system, its corresponding module in the initial coordinate system is found out, and the grayscale value of that module is assigned to the point to realize the correction of the QR code image. Coordinates of the three detection patterns, the locating point in the initial coordination system, and the correction coordinate system may be readily obtained according to different version numbers. At the same time, shortcomings caused by edge detection may be avoided, and a favorable correction effect may be obtained.

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Beijing, China

Wanyi Che