import sensor, image, time

sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.QVGA)


sensor.skip_frames(time = 2000) # Give the user time to get ready.

i=0
m=320
n=240
temp = sensor.alloc_extra_fb(m, n, sensor.GRAYSCALE)
img_past = sensor.alloc_extra_fb(m, n, sensor.GRAYSCALE)
img_now = sensor.alloc_extra_fb(m, n, sensor.GRAYSCALE)
kernel_edge = [1, 1,  1, \
          1,  -8,  1, \
           1,  1,  1]


img_past=sensor.snapshot()
clock = time.clock()
while i < 1000:
    # 获取当前灰度图
    img_now = sensor.snapshot()

    #当前灰度图归一化
    #temp.normalize(0, 255)
#    img_now.replace(temp)
    #差分图的绝对值
    img_now.save("temp3_withoutdifference/img_now"+str(i)+".bmp")
    img_diff2 = img_now.difference(img_past)
    img_diff2.morph(1, kernel_edge)
    img_diff2.save("temp2/diff"+str(i)+".bmp")



    i+=1
    img_past.replace(img_now)
    print(clock.fps())