Sequencing in 2 combo arrays using Python

Question

I am trying to turn picture information from 13 colorful blocks into some texts. For example, I need to know how many yellow and blue blocks are here and their sequence.

"C: \ target.jpg"

"C: \ blue.jpg"

"C: \ yellow.jpg"

I have:

import cv2 import numpy as np img_rgb = cv2.imread("c:\\target.jpg") img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY) template = cv2.imread('c:\\blue.jpg',0) # template = cv2.imread('c:\\blue.jpg',0) w, h = template.shape[::-1] res = cv2.matchTemplate(img_gray,template,cv2.TM_CCOEFF_NORMED) threshold = 0.99 loc = np.where (res >= threshold) # if print loc # (array([ 3, 31, 59, 87, 115, 143, 171, 199, 227, 255, 283, 311, 339], dtype=int64), array([7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7], dtype=int64)) print str(loc[0] + loc[1]) 

When I run them separately, it gives the following results:

 [ 13 41 69 97 125 153 181 209 237 265 293 321 349] 

and

 [ 10 38 66 94 122 150 178 206 234 262 290 318 346] 

Well, these are all 13 numbers, but I don’t know how to handle them.

How can I turn them into texts such as:

"blue, yellow, blue, yellow, blue, blue, yellow, yellow, blue, yellow, blue, yellow, blue, yellow."

Answer 1

Here's a pretty simple solution that just reads a strip of pixels in the center:

 from PIL import Image im = Image.open(filename) xMin, yMin, xMax, yMax = im.getbbox() x = (xMin + xMax) / 2 colors = [] oldColor = None for y in xrange(yMin, yMax): r, g, b = im.getpixel((x, y)) if r > 240 and g > 240 and b > 240: newColor = 'white' elif g > 150 and b > 150: newColor = 'blue' elif r > 150 and g > 150: newColor = 'yellow' else: newColor = 'unknown' if newColor != oldColor: if newColor != 'white': colors.append(newColor) oldColor = newColor print colors 

He prints:

 ['blue', 'yellow', 'blue', 'yellow', 'blue', 'blue', 'yellow', 'yellow', 'blue', 'yellow', 'blue', 'yellow', 'blue'] 

Answer 2

There are several ways to convert from these numbers to a string, I would do

 bl=[ 13, 41, 69, 97,125,153,181,209,237,265,293,321,349] yl=[ 10, 38, 66, 94,122,150,178,206,234,262,290,318,346] x=sorted(bl+yl) out=', '.join(['blue' if y in bl else 'yellow' for y in x]) print out