覆盆子pi picamera-图像比较

Question

Im trying to detect movement in between 2 pictures taken from the raspberry pi picamera. i'm doing this by comparing de raw pixeldata with eachother. Below is a simple script which i'm using to test the comparison.

import picamera
import datetime
from fractions import Fraction
import time
import numpy as np

oldImage = np.empty((48, 64, 3))
newImage = np.empty((48, 64, 3))
color_offset = 25

with picamera.PiCamera() as camera:
    camera.resolution = (64,48)
    camera.start_preview()
    time.sleep(2)

    camera.capture(oldImage, "rgb")
    time.sleep(5)
    camera.capture(newImage, "rgb")

    x = 0
    y = 0
    diff = 0

    while(x < np.size(newImage, 0)):
        while(y < np.size(newImage, 1)):
            val1 = newImage[x, y, 0] + newImage[x, y, 1] + newImage[x, y, 2]
            val2 = oldImage[x, y, 0] + oldImage[x, y, 1] + oldImage[x, y, 2]
            print(val1)
            print(val2)
            pd = abs(val2 - val1)
            print(pd)

            if(pd > color_offset):
                diff += 1
            y +=1
        x += 1
        y=0

    print(str(diff))

In the script i start the camera, take the first picture, wait a few seconds, take the second picture and calculate the difference. However evertime i run this script, the "val1" variable is always 0.0. Any help would be appreciated.

Answer 1

So with a 2x2 "image", your color value addition

import numpy as np

newImage = np.array([[[0,0,0], [1,0,0]], [[0,1,0], [0,1,1]]])

x = 0
y = 0
while(x < np.size(newImage, 0)):
    while(y < np.size(newImage, 1)):
        val1 = newImage[x, y, 0] + newImage[x, y, 1] + newImage[x, y, 2]
        print(val1)
        y +=1
    x += 1
    y = 0

produces

0
1
1
2

as I would expect.

What result do you expect? Is your data OK (provide sample data)?