如何使用 cv2.rectangle() 创建随机颜色边界框

Question

我正在尝试创建随机颜色并尝试根据个人边界框的不同颜色进行更改

COLORS = np.random.randint(0, 255, [1000, 3])
def visualize_detection_results(img_np, active_actors, prob_dict):
    score_th = 0.30
    action_th = 0.20

    # copy the original image first
    disp_img = np.copy(img_np)
    H, W, C = img_np.shape
    #for ii in range(len(active_actors)):
    for ii in range(len(active_actors)):
        cur_actor = active_actors[ii]
        actor_id = cur_actor['actor_id']
        cur_act_results = prob_dict[actor_id] if actor_id in prob_dict else []
        try:
            cur_box, cur_score, cur_class = cur_actor['all_boxes'][-16], cur_actor['all_scores'][0], 1
        except IndexError:
            continue

        if cur_score < score_th: 
            continue

        top, left, bottom, right = cur_box


        left = int(W * left)
        right = int(W * right)

        top = int(H * top)
        bottom = int(H * bottom)

        conf = cur_score
        #label = bbox['class_str']
        # label = 'Class_%i' % cur_class
        label = obj.OBJECT_STRINGS[cur_class]['name']
        message = '%s_%i: %% %.2f' % (label, actor_id,conf)
        action_message_list = ["%s:%.3f" % (actres[0][0:7], actres[1]) for actres in cur_act_results if actres[1]>action_th]
        # action_message = " ".join(action_message_list)

        color = COLORS[actor_id] 
        print("######",color) # prints[73   0 234]

        cv2.rectangle(disp_img, (left,top), (right,bottom), color, 3)

        font_size =  max(0.5,(right - left)/50.0/float(len(message)))
        cv2.rectangle(disp_img, (left, top-int(font_size*40)), (right,top), color, -1)
        cv2.putText(disp_img, message, (left, top-12), 0, font_size, (255,255,255)-color, 1)

        #action message writing
        cv2.rectangle(disp_img, (left, top), (right,top+10*len(action_message_list)), color, -1)
        for aa, action_message in enumerate(action_message_list):
            offset = aa*10
            cv2.putText(disp_img, action_message, (left, top+5+offset), 0, 0.5, (255,255,255)-color, 1)

    return disp_img

追溯：

Traceback (most recent call last):
  File "detect_actions.py", line 310, in <module>
    main()
  File "detect_actions.py", line 177, in main
    out_img = visualize_detection_results(tracker.frame_history[-16], tracker.active_actors, prob_dict)
  File "detect_actions.py", line 240, in visualize_detection_results
    cv2.rectangle(disp_img, (left,top), (right,bottom), color, 3)
TypeError: Scalar value for argument 'color' is not numeric

color在这种情况下，数组不被接受为数字。我在 StackOverflow 上尝试了一些方法，但它不起作用。我opencv version 3.3.0很感激你的建议。谢谢我已经尝试过：

color = np.array((np.asscalar(np.int16(color[0])),np.asscalar(np.int16(color[1])),np.asscalar(np.int16(color[2]))))

Answer 1

要生成随机 BGR 值，您可以使用np.random()然后将其插入到cv2.rectangle()

color = list(np.random.random(size=3) * 256)
cv2.rectangle(image, (x, y), (x + w, y + h), color, 4)

这是使用此输入图像的示例

我们找到轮廓并在每个数字周围绘制一个随机颜色矩形

import cv2
import numpy as np

image = cv2.imread('1.png')
gray = 255 - cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

cnts = cv2.findContours(gray, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
for c in cnts:
    x,y,w,h = cv2.boundingRect(c)
    color = list(np.random.random(size=3) * 256)
    cv2.rectangle(image, (x, y), (x + w, y + h), color, 4)

cv2.imshow('image', image)
cv2.imwrite('image.png', image)
cv2.waitKey()

Answer 2

通过创建具有“asscalar”值的 numpy 数组，您可以重新引入使用“asscalar”解决的问题。

要将颜色用作变量，可以使用以下任一解决方案：

# without numpy
tmp = [30,15,130]
color= (tmp[0],tmp[1],tmp[2])
cv2.rectangle(img,(1,1), (30,30),color,3)
# with numpy
tmp = np.array([30,15,130])
color= (np.asscalar(tmp[0]),np.asscalar(tmp[1]),np.asscalar(tmp[2]))
cv2.rectangle(img,(1,1), (30,30),color,3)
# without array
color= (30,15,130)
cv2.rectangle(img,(1,1), (30,30),color,3)

更具体到您的代码：您将颜色生成为二维数组，但是在使用 asscalar 时您没有考虑到这一点。尝试这个：

COLORS = np.random.randint(0, 255, [10, 3])
actor_id = 2
color= (np.asscalar(COLORS[actor_id][0]),np.asscalar(COLORS[actor_id][1]),np.asscalar(COLORS[actor_id][2]))
cv2.rectangle(img,(1,1), (30,30),color,3)