aboutsummaryrefslogtreecommitdiff
path: root/signature.cpp
blob: b912198fe1ad93ba3cb85179164bdc17a10ccab7 (plain) (blame)
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
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
//Chris Xiong 2022
//License: MPL-2.0
/* Based on
 * H. Chi Wong, M. Bern and D. Goldberg,
 * "An image signature for any kind of image," Proceedings.
 * International Conference on Image Processing, 2002, pp. I-I,
 * doi: 10.1109/ICIP.2002.1038047.
 * and
 * libpuzzle (also an implementation of the article above).
 */
#include "signature.hpp"

#include <algorithm>
#include <fstream>
#include <cmath>
#include <cstdint>
#include <vector>

#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/imgproc.hpp>

#include "compressed_vector.hpp"
#include "imageutil.hpp"

static signature_config _default_cfg =
{
    9,     //slices
    3,     //blur_window
    2,     //min_window
    true,  //crop
    false, //comp
    0.5,   //pr
    1./128,//noise_threshold
    0.05,  //contrast_threshold
    0.25   //max_cropping
};

class signature_priv
{
private:
    cv::Mat fimg;
    cv::Mat lch;
    std::vector<float> lv;
    compressed_vector<uint8_t, 3> ct;
    std::vector<uint8_t> uct;
    bool compressed;
    signature_config cfg;
public:
    float get_light_charistics_cell(int x, int y, int w, int h);
    void get_light_charistics();
    void get_light_variance();
    void get_signature();
    double length() const;
    double distance(const signature_priv &o) const;
    bool operator==(const signature_priv &o) const;
    void dump() const;
    friend class signature;
    friend struct signature_hash;
};

float signature_priv::get_light_charistics_cell(int x, int y, int w, int h)
{
    return cv::mean(fimg(cv::Range(y, y + h), cv::Range(x, x + w)))[0];
}

void signature_priv::get_light_charistics()
{
    double windowx, windowy;
    int iw, ih, slc;
    iw = fimg.size().width;
    ih = fimg.size().height;
    slc = cfg.slices;
    windowx = iw / (double)slc / 2;
    windowy = ih / (double)slc / 2;
    int windows = round(std::min(iw, ih) / slc * cfg.pr);
    if (windows < cfg.min_window)
        windows = cfg.min_window;
    double ww = (iw - 1) / (slc + 1.);
    double wh = (ih - 1) / (slc + 1.);
    double wxs = 0, wys = 0;
    if (windows < ww) wxs = (ww - windows) / 2.;
    if (windows < wh) wys = (wh - windows) / 2.;
    lch.create(slc, slc, CV_32F);
    float *lp = lch.ptr<float>(0);
    for (int i = 0; i < slc; ++i)
    {
        for (int j = 0; j < slc; ++j)
        {
            double cwx, cwy;
            cwx = i * (iw - 1) / (slc + 1.) + windowx;
            cwy = j * (ih - 1) / (slc + 1.) + windowy;
            int x = (int)round(cwx + wxs);
            int y = (int)round(cwy + wys);
            int cww, cwh;
            cww = (iw - x < windows) ? 1 : windows;
            cwh = (ih - y < windows) ? 1 : windows;
            *(lp++) = get_light_charistics_cell(x, y, cww, cwh);
        }
    }
}

void signature_priv::get_light_variance()
{
    const int dx[8] = {-1, -1, -1,  0,  0,  1,  1,  1};
    const int dy[8] = {-1,  0,  1, -1,  1, -1,  0,  1};
    int slc = cfg.slices;
    float *lp = lch.ptr<float>(0);
    for (int x = 0; x < slc; ++x)
    {
        for (int y = 0; y < slc; ++y)
        {
            for (int k = 0; k < 8; ++k)
            {
                int nx = x + dx[k];
                int ny = y + dy[k];
                if (nx < 0 || ny < 0 || nx >= slc || ny >= slc)
                    lv.push_back(0);
                else
                    lv.push_back(*lp - *(lp + dx[k] * slc + dy[k]));
            }
            ++lp;
        }
    }
}

void signature_priv::get_signature()
{
    std::vector<double> lights;
    std::vector<double> darks;
    for (float &l : lv)
    {
        if (fabsf(l) > cfg.noise_threshold)
        {
            if (l > 0)
                lights.push_back(l);
            else
                darks.push_back(l);
        }
    }
    double lth = image_util::median(lights);
    double dth = image_util::median(darks);
    if (cfg.compress)
    {
        compressed = true;
        for (float &l : lv)
        {
            if (fabsf(l) > cfg.noise_threshold)
            {
                if (l > 0)
                    ct.push_back(l > lth ? 4 : 3);
                else
                    ct.push_back(l < dth ? 0 : 1);
            }
            else ct.push_back(2);
        }
    }
    else
    {
        compressed = false;
        for (float &l : lv)
        {
            if (fabsf(l) > cfg.noise_threshold)
            {
                if (l > 0)
                    uct.push_back(l > lth ? 4 : 3);
                else
                    uct.push_back(l < dth ? 0 : 1);
            }
            else uct.push_back(2);
        }
    }
}

double signature_priv::length() const
{
    if (compressed)
        return image_util::length(ct, (uint8_t)2);
    else
        return image_util::length(uct, 2);
}

double signature_priv::distance(const signature_priv &o) const
{
    if (compressed && o.compressed)
        return image_util::distance(ct, o.ct) / (image_util::length(ct, uint8_t(2)) + image_util::length(o.ct, uint8_t(2)));
    else
        return image_util::distance(uct, o.uct) / (image_util::length(uct, uint8_t(2)) + image_util::length(o.uct, uint8_t(2)));
}

bool signature_priv::operator==(const signature_priv &o) const
{
    if (compressed && o.compressed)
        return ct == o.ct;
    else
        return uct == o.uct;
}

void signature_priv::dump() const
{
    if (!compressed)
        for (auto &x : this->uct)
            printf("%u ", x);
    else
        for (size_t i = 0; i < this->ct.size(); ++i)
            printf("%u ", this->ct.get(i));
    printf("\n");
}

signature::signature() = default;
signature::signature(signature_priv* _p) : p(_p){}
signature::~signature() = default;

void signature::dump() const
{
    if (p) p->dump();
}

bool signature::valid() const
{return (bool)p;}

signature signature::clone() const
{
    return signature(*this);
}

double signature::length() const
{
    if (!p) {fprintf(stderr, "length: null signature"); return -1;}
    return p->length();
}

double signature::distance(const signature &o) const
{
    if (!p || !o.p) {fprintf(stderr, "distance: null signature"); return -1;}
    return p->distance(*o.p);
}

bool signature::operator==(const signature &o) const
{
    if (!p || !o.p) {fprintf(stderr, "eq: null signature"); return false;}
    return *p == *o.p;
}

std::string signature::to_string() const
{
    if (!p || !p->compressed) return std::string();
    Base64Encoder enc;
    size_t sz = p->ct.size();
    enc.encode_data(&p->cfg, sizeof(signature_config));
    enc.encode_data(&sz, sizeof(size_t));
    enc.encode_data(p->ct.internal_data(), p->ct.internal_container_size() * 8);
    return enc.finalize();
}

signature signature::from_string(std::string &&s)
{
    signature_priv *p = new signature_priv;
    Base64Decoder dec(std::move(s));
    size_t sz;
    p->compressed = true;
    size_t s1 = dec.decode_data(&p->cfg, sizeof(signature_config));
    size_t s2 = dec.decode_data(&sz, sizeof(size_t));
    size_t s3 = dec.decoded_length() - s1 - s2;
    p->ct.internal_set_size(sz);
    p->ct.internal_container_resize(s3 / 8);
    dec.decode_data(p->ct.internal_data(), s3);
    return signature(p);
}

signature signature::from_preprocessed_matrix(cv::Mat *m, const signature_config &cfg)
{
    signature_priv *p = new signature_priv;
    p->cfg = cfg;

    if (cfg.crop)
        p->fimg = image_util::crop(*m, cfg.contrast_threshold, cfg.max_cropping);
    else
        p->fimg = *m;
    if (cfg.blur_window > 1)
        cv::blur(p->fimg, p->fimg, cv::Size(cfg.blur_window, cfg.blur_window));
    p->get_light_charistics();
    p->get_light_variance();
    p->get_signature();
    p->fimg.release();
    p->lch.release();
    p->lv.clear();
    return signature(p);
}

signature signature::from_cvmatrix(cv::Mat *m, const signature_config &cfg)
{
    cv::Mat ma, bw;
    double sc = 1;
    switch (m->depth())
    {
        case CV_8U: sc = 1. / 255; break;
        case CV_16U: sc = 1. / 65535; break;
    }
    m->convertTo(ma, CV_32F, sc);
    if (m->channels() == 4)
        ma = image_util::blend_white(ma);
    if (ma.channels() == 3)
        cv::cvtColor(ma, bw, cv::COLOR_RGB2GRAY);
    else
        bw = ma;
    return signature::from_preprocessed_matrix(&bw, cfg);
}

signature signature::from_file(const char *fn, const signature_config &cfg)
{
    cv::Mat img = cv::imread(fn, cv::IMREAD_UNCHANGED);
    return signature::from_cvmatrix(&img, cfg);
}

signature signature::from_path(const std::filesystem::path &path, const signature_config &cfg)
{
    cv::Mat img = image_util::imread_path(path, cv::IMREAD_UNCHANGED);
    return signature::from_cvmatrix(&img, cfg);
}

signature_config signature::default_cfg()
{
    return _default_cfg;
}

size_t signature_hash::operator()(signature const& sig) const noexcept
{
    if (sig.p->compressed)
        return compressed_vector_hash<uint8_t, 3>{}(sig.p->ct);
    else
    {
        size_t ret = 0;
        for (uint8_t &v : sig.p->uct)
            ret ^= v + 0x9e3779b9 + (ret << 6) + (ret >> 2);
        return ret;
    }
}