File size: 3,296 Bytes
be94e5d |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 |
// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
// Copyright (c) 2020-2021 darkliang wangberlinT Certseeds
#include "../precomp.hpp"
#include "ean13_decoder.hpp"
// three digit decode method from https://baike.baidu.com/item/EAN-13
namespace cv {
namespace barcode {
static constexpr size_t EAN13BITS_NUM = 95;
static constexpr size_t EAN13DIGIT_NUM = 13;
// default thought that mat is a matrix after binary-transfer.
/**
* decode EAN-13
* @prama: data: the input array,
* @prama: start: the index of start order, begin at 0, max-value is data.size()-1
* it scan begin at the data[start]
*/
Result Ean13Decoder::decode(const vector<uchar> &data) const
{
string result;
char decode_result[EAN13DIGIT_NUM + 1]{'\0'};
if (data.size() < EAN13BITS_NUM)
{
return Result("Wrong Size", Result::BARCODE_NONE);
}
pair<uint, uint> pattern;
if (!findStartGuardPatterns(data, pattern))
{
return Result("Begin Pattern Not Found", Result::BARCODE_NONE);
}
uint start = pattern.second;
Counter counter(vector<int>{0, 0, 0, 0});
size_t end = data.size();
int first_char_bit = 0;
// [1,6] are left part of EAN, [7,12] are right part, index 0 is calculated by left part
for (int i = 1; i < 7 && start < end; ++i)
{
int bestMatch = decodeDigit(data, counter, start, get_AB_Patterns());
if (bestMatch == -1)
{
return Result("Decode Error", Result::BARCODE_NONE);
}
decode_result[i] = static_cast<char>('0' + bestMatch % 10);
start = counter.sum + start;
first_char_bit += (bestMatch >= 10) << i;
}
decode_result[0] = static_cast<char>(FIRST_CHAR_ARRAY()[first_char_bit >> 2] + '0');
// why there need >> 2?
// first, the i in for-cycle is begin in 1
// second, the first i = 1 is always
Counter middle_counter(vector<int>(MIDDLE_PATTERN().size()));
if (!findGuardPatterns(data, start, true, MIDDLE_PATTERN(), middle_counter, pattern))
{
return Result("Middle Pattern Not Found", Result::BARCODE_NONE);
}
start = pattern.second;
for (int i = 0; i < 6 && start < end; ++i)
{
int bestMatch = decodeDigit(data, counter, start, get_A_or_C_Patterns());
if (bestMatch == -1)
{
return Result("Decode Error", Result::BARCODE_NONE);
}
decode_result[i + 7] = static_cast<char>('0' + bestMatch);
start = counter.sum + start;
}
Counter end_counter(vector<int>(BEGIN_PATTERN().size()));
if (!findGuardPatterns(data, start, false, BEGIN_PATTERN(), end_counter, pattern))
{
return Result("End Pattern Not Found", Result::BARCODE_NONE);
}
result = string(decode_result);
if (!isValid(result))
{
return Result("Wrong: " + result.append(string(EAN13DIGIT_NUM - result.size(), ' ')), Result::BARCODE_NONE);
}
return Result(result, Result::BARCODE_EAN_13);
}
Ean13Decoder::Ean13Decoder()
{
this->bits_num = EAN13BITS_NUM;
this->digit_number = EAN13DIGIT_NUM;
}
}
}
|