Absolute coding method and bar code thereof

Abstract

The embodiment of the invention discloses an absolute coding method and a bar code thereof and relates to the field of precise surveying instrument manufacturing. The coding method only needs two to three code elements, is an absolute coding method which is easy to implement and has strong error correcting capability, and is very convenient to depict whether on a scale or on a dial. According to the absolute coding method, an effective bar code represents information of the location thereof, the bar code includes a plurality of code elements with equal width D, and each code element is composed of a black code and two white codes which are respectively located at the two sides of the black code, wherein the center line of each black code and the center line of the corresponding code element overlap, the width d of the black codes is smaller than D, different code elements are formed due to different width d of the black codes, and the width of the white codes are equal to half of the difference between D and d. The absolute coding method and the bar code thereof of the invention are applied to absolute coding of precise surveying instruments.

Description

technical field [0001] The invention relates to the field of manufacturing precision surveying and mapping instruments, in particular to an absolute coding method and a barcode thereof. Background technique [0002] At present, the absolute encoding methods provided by the prior art mainly include correlation method, geometric method and phase method. The Swiss LEICA company once proposed an absolute coding method. A standard code of this method adopts a "black + white (yellow)" code, wherein the code widths of the black code and the white (yellow) code are 1 to 15 times of a certain constant. In this way, 225 different codes can be formed. When this coding method is applied to the bar code of the digital level, the constant = 2.025mm is taken, and 41 codes are selected from the 225 codes for combination. This coding method is called pseudo-random Coding method, decoding method is to align the images of at least 6 consecutive barcodes acquired by the CCD sensor with the ima...

AI Technical Summary

Problems solved by technology

[0003] These companies apply their respective encoding principles to produce digital levels and total stations (electronic theodolites). Although they have obtained products with high measurement accuracy, their encoding methods have obvious defects: there are too many types of barcodes, It brings great difficulty to the description of the scale or dial; the information represented by the barcode is uneven, which makes the accuracy of the measurement results at different positions different; the encoding and decoding operations are complex, the calculation is large, and the measurement speed is slow or the hardware cost is high

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