How to access the COLMAP database.

COLMAP_DB.py

#!/usr/bin/env python
# coding: utf-8

import sqlite3
import numpy as np

import matplotlib.pyplot as plt
from PIL import Image

con = sqlite3.connect('Nuketown.db')
plt.rcParams['figure.figsize'] = [20, 20]

cur = con.cursor()

for row in cur.execute('SELECT * FROM cameras'):
    print(row[0:3])
    print(np.frombuffer(row[4], dtype=np.float64))
print(cur.description)

for row in cur.execute('SELECT * FROM images'):
    print(row)

print(cur.description)

count = 0
for row in cur.execute('SELECT * FROM keypoints'):
    image_id, rows, cols, data = row
    array = np.frombuffer(data, dtype=np.float32)
    array = array.reshape((rows, cols))
    break

img = Image.open('01285.jpg')
plt.rcParams['figure.figsize'] = [15, 15]
plt.scatter(array[:, 0], array[:, 1], alpha=0.5)
plt.imshow(img)
plt.show()
print(cur.description)

count = 0
for row in cur.execute('SELECT * FROM descriptors'):
    image_id, rows, cols, data = row
    array = np.frombuffer(data, dtype=np.uint8)
    array = array.reshape((rows, cols))
    print(array.shape)
    break

print(cur.description)


def image_ids_to_pair_id(image_id1, image_id2):
    if image_id1 > image_id2:
        return 2147483647 * image_id2 + image_id1
    else:
        return 2147483647 * image_id1 + image_id2


def pair_id_to_image_ids(pair_id):
    image_id2 = pair_id % 2147483647
    image_id1 = int((pair_id - image_id2) / 2147483647)
    return image_id1, image_id2


count = 0
for row in cur.execute('SELECT * FROM matches'):
    pair_id, rows, cols, data = row
    array = np.frombuffer(data, dtype=np.uint32)
    array = array.reshape((rows, cols))
    print(array)
    print(pair_id_to_image_ids(pair_id))
    print(array.shape)
    break
print(cur.description)

count = 0
for row in cur.execute('SELECT * FROM two_view_geometries'):
    pair_id, rows, cols, data, config, F, E, H = row
    array = np.frombuffer(data, dtype=np.uint32)
    array = array.reshape((rows, cols))
    break

print(cur.description)

for row in cur.execute('SELECT * FROM keypoints WHERE image_id IS 1'):
    image_id, rows, cols, data = row
    array1 = np.frombuffer(data, dtype=np.float32)
    array1 = array1.reshape((rows, cols))

for row in cur.execute('SELECT * FROM keypoints WHERE image_id IS 2'):
    image_id, rows, cols, data = row
    array2 = np.frombuffer(data, dtype=np.float32)
    array2 = array2.reshape((rows, cols))

img1 = Image.open('01285.jpg')
img2 = Image.open('01286.jpg')

for i in range(0, array.shape[0], 100):
    idx1, idx2 = array[i][0], array[i][1]

    x1, y1 = array1[idx1][0], array1[idx1][1]
    x2, y2 = array2[idx2][0], array2[idx2][1]

    plt.plot([x1, x2 + 2560], [y1, y2], alpha=0.2)

plt.imshow(np.hstack([img1, img2]))
plt.show()

print(cur.description)