Tensorflow对象检测API :当检测到特定类时，将GPIO引脚调高

Question

我正在使用Tensorflow对象检测API来检测respberry pi上的对象，它是实时的对象检测，并且我让它工作得很好。它可以绘制带有标签的边界框和它检测到的类的会议分数。所以我的问题是：

当检测到特定的类时，我如何将GPIO引脚设置为高，假设特定的类是“person”，而我希望引脚11为高，我该如何做？

下面是我认为相关的代码：

# Perform the actual detection by running the model with the image as input
        (boxes, scores, classes, num) = sess.run(
            [detection_boxes, detection_scores, detection_classes, num_detections],
            feed_dict={image_tensor: frame_expanded})

        # Draw the results of the detection (aka 'visulaize the results')
        vis_util.visualize_boxes_and_labels_on_image_array(
            frame,
            np.squeeze(boxes),
            np.squeeze(classes).astype(np.int32),
            np.squeeze(scores),
            category_index,
            use_normalized_coordinates=True,
            line_thickness=3,
            min_score_thresh=0.40)

        cv2.putText(frame,"FPS: {0:.2f}".format(frame_rate_calc),(30,50),font,1,(255,255,0),2,cv2.LINE_AA)

        # All the results have been drawn on the frame, so it's time to display it.
        cv2.imshow('Object detector', frame)

np.squeeze(classes).astype(np.int32)可能是获取检测到的类的一种方法吗？

Answer 1

您可以通过/sys/class/gpio接口控制GPIO。在我的例子中，我使用了另一个嵌入式系统。但它的工作原理应该大同小异。我正在使用bash命令。但是您可以很容易地将它们替换为Python文件操作。

ubuntu@localhost:/sys/class/gpio$ ls
export  gpiochip1008  gpiochip1016  gpiochip890  unexport

可以有多个gpio接口。要使用这些接口：

启用前两位

echo 1008 > export
echo 1009 > export

这将为新IO文件创建一个编号：

root@localhost:/sys/class/gpio# ls -al
total 0
drwxr-xr-x  2 root root    0 Feb 11 17:05 .
drwxr-xr-x 45 root root    0 Feb 11 16:45 ..
--w-------  1 root root 4096 Feb 11 17:08 export
lrwxrwxrwx  1 root root    0 Feb 11 16:53 gpio1008 -> ../../devices/soc0/amba_pl/41200000.gpio/gpiochip1/gpio/gpio1008
lrwxrwxrwx  1 root root    0 Feb 11 17:02 gpio1009 -> ../../devices/soc0/amba_pl/41200000.gpio/gpiochip1/gpio/gpio1009
--w-------  1 root root 4096 Feb 11 17:05 unexport

将输出方向设置为'out‘('in’是默认值)

echo out > gpio1008/direction
echo out > gpio1009/direction

使大头针升高：

echo 1 > gpio1016/value
echo 1 > gpio1017/value

Answer 2

您可以使用.3或其他方法过滤检测分数。如果检测类在过滤后的索引中包含该类，则可以将high发送到pin

from gpiozero import LED

led = LED(11) #pin you plug led
filter=0.3 #filter of scores if you decrease it program finds more item
selected_class=4 #you want to find class
isledhigh=False
...
    makeledhigh=False
    (boxes, scores, classes, num) = sess.run(
            [detection_boxes, detection_scores, detection_classes, num_detections],
            feed_dict={image_tensor: frame_expanded})
    for i in range(int(num[0])):
        if classes[i]==selected_class and scores[i]>=filter:
            makeledhigh=True
    if makeledhigh and !isledhigh:
        led.on()
        isledhigh=True
    if isledhigh and !makeledhigh:
        led.off()
        isledhigh=False

Answer 3

代码非常简单：

import RPi.GPIO as GPIO

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(11, GPIO.OUT, initial=GPIO.LOW)
GPIO.setup(13, GPIO.OUT, initial=GPIO.LOW)

if object_detected_class==1:
    GPIO.output(11, GPIO.HIGH)

else: #other class
    GPIO.output(13, GPIO.HIGH)