python-3.x - Python OpenCV 模板匹配结果不佳

Question

我正在尝试构建一个可以从在线网站识别扑克牌的工具。

我认为这项任务将是微不足道的。收集所有可能的卡片，将它们粘贴到一张图像中，获取一张“未知”卡片，在 all_cards_image 上运行模板匹配，收集匹配的点，将其与 (x,y) = "Ah" 的字典进行比较，瞧。

但是模板匹配给出了这样的命中和未命中结果，有些单卡根本无法识别，有些单卡同时识别为红桃4、红桃5和红桃6。梅花 8 被识别为黑桃 8，以此类推。当没有卡片存在时，它会匹配整个模板图像。

我找不到可以带来满意结果的阈值。

我附上了整个代码以及图像。

我很清楚，我可以走只识别卡片等级的路线，也许在黑白图像上并用颜色（蓝色，绿色，红色，黑色）掩盖西装，然后再匹配它们。我只是希望有一个简单的模板匹配解决方案而无需跳过箍。

代码中包含所有卡片（all_cards.jpg）的第一张图片：

第二张图片（随机截图），所有其他细节都改为白色，以免图像太大，在代码中命名为“Screenshot_to_test_card_recognition_reduced.png”：

import cv2
import numpy as np
import os

# defining constants for positions, card width and height in a screenshot 
CARD_HEIGHT = 59
CARD_WIDTH = 90
HORIZONTAL_SPACE = 5
HORIZONTAL_OFFSET_2 = 1463
VERTICAL_OFFSET_2 = 1047
FIRST_CARD_X = 955
FIRST_CARD_Y = 370
FLOPS_STARTING_POINTS = [(FIRST_CARD_X, FIRST_CARD_Y), (FIRST_CARD_X + HORIZONTAL_OFFSET_2, FIRST_CARD_Y), \
                        (FIRST_CARD_X, FIRST_CARD_Y + VERTICAL_OFFSET_2), \
                        (FIRST_CARD_X + HORIZONTAL_OFFSET_2, FIRST_CARD_Y + VERTICAL_OFFSET_2)]

# show image function
def show_image(img, title = "Unnamed"):
    cv2.imshow(title, img)
    cv2.waitKey(0)
    cv2.destroyAllWindows()


# INSERT FOLDER WITH FILES
saved_folder = "D:\\WinPython 32 3.4\\WinPython-32bit-3.4.4.6Qt5\\notebooks\\Named cards"

template_image = os.path.join(saved_folder, 'all_cards.jpg')
screenshot = os.path.join(saved_folder, 'Screenshot_to_test_card_recognition_reduced.png')


img_rgb = cv2.imread(screenshot)
img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)

CORRECTION_FOR_SEARCH_WIDTH = 0 #60
CORRECTION_FOR_SEARCH_HEIGTH = 0 #20

# LOOP THROUGH ALL FIVE CARDS FOR EACH FLOP ON 4 TABLES 

for point in FLOPS_STARTING_POINTS:
    flop_starting_x, flop_starting_y = point
        
    for card in range (0,5):
        
        start_x = flop_starting_x + ((HORIZONTAL_SPACE) * card) + ((CARD_WIDTH) * card)
        end_x = start_x + CARD_WIDTH - CORRECTION_FOR_SEARCH_WIDTH
        start_y = flop_starting_y
        end_y = start_y + CARD_HEIGHT - CORRECTION_FOR_SEARCH_HEIGTH
        
        template = img_gray[start_y:end_y,start_x:end_x]
        w, h = template.shape[::-1]
        
        show_image(template)
        
        all_cards_image = cv2.imread(template_image)
        grey_all_cards_image = cv2.cvtColor(all_cards_image, cv2.COLOR_BGR2GRAY)
        
        res = cv2.matchTemplate(grey_all_cards_image,template,cv2.TM_CCOEFF_NORMED)
        threshold = 0.85
        loc = np.where( res >= threshold)
        for pt in zip(*loc[::-1]):
            cv2.rectangle(all_cards_image, pt, (pt[0] + w, pt[1] + h), (0,0,255), 2)
            
        print(loc)
            
        show_image(all_cards_image)

标签： python-3.xopencvimage-processing