tuple error while cropping

Question

i would like to crop the image using this command.

def imgCrop(im):
        box = (0, 150, 640, 200)
        region = im.crop(box)
        region.save('crop.jpg')
        return region

then the error come out like this

AttributeError: 'tuple' object has no attribute 'crop'

and actually im refering to http://effbot.org/imagingbook/image.htm, this method is correct. Please advise.

Here my full program, please advise

import cv2
from cv2 import *
from PIL import Image 
import RPi.GPIO as GPIO
import time
im = 0

GPIO.setwarnings(False)

GPIO.setmode(GPIO.BCM)

GPIO.setup(27, GPIO.OUT)        #Input 1
GPIO.setup(22, GPIO.OUT)        #Input 2
GPIO.setup(9, GPIO.OUT)         #Input 3
GPIO.setup(10, GPIO.OUT)        #Input 4
GPIO.setup(7, GPIO.OUT)         #Enable 1
GPIO.setup(8, GPIO.OUT)         #Enable 2

GPIO.setup(15, GPIO.IN)         #turn right
GPIO.setup(18, GPIO.IN)         #turn left
GPIO.setup(23, GPIO.IN)         #backward
GPIO.setup(24, GPIO.IN)         #forward

p = GPIO.PWM(7,50)
q = GPIO.PWM(8,50)
p.start(0)
q.start(0)

def forward():
    p.ChangeDutyCycle(100)  
    q.ChangeDutyCycle(100)
    GPIO.output(27, GPIO.HIGH)      #input 1 is LOW
    GPIO.output(22, GPIO.LOW)       #input 2 is High
    GPIO.output(9, GPIO.HIGH)       #input 1 is LOW
    GPIO.output(10, GPIO.LOW)       #input 2 is High

def backward():
    p.ChangeDutyCycle(100)  
    q.ChangeDutyCycle(100)
    GPIO.output(27, GPIO.LOW)       #input 1 is LOW
    GPIO.output(22, GPIO.HIGH)      #input 2 is High
    GPIO.output(9, GPIO.LOW)        #input 1 is LOW
    GPIO.output(10, GPIO.HIGH)      #input 2 is High

def left():
    p.ChangeDutyCycle(100)  
    q.ChangeDutyCycle(100)
    GPIO.output(27, GPIO.LOW)       #input 1 is LOW
    GPIO.output(22, GPIO.HIGH)      #input 2 is High
    GPIO.output(9, GPIO.HIGH)       #input 1 is LOW
    GPIO.output(10, GPIO.LOW)

def right():
    p.ChangeDutyCycle(100)  
    q.ChangeDutyCycle(100)
    GPIO.output(27, GPIO.HIGH)      #input 1 is LOW
    GPIO.output(22, GPIO.LOW)       #input 2 is High
    GPIO.output(9, GPIO.LOW)        #input 1 is LOW
    GPIO.output(10, GPIO.HIGH)

def stop():
    p.ChangeDutyCycle(100)  
    q.ChangeDutyCycle(100)
    GPIO.output(27, GPIO.LOW)       #input 1 is LOW
    GPIO.output(22, GPIO.LOW)       #input 2 is High
    GPIO.output(9, GPIO.LOW)        #input 1 is LOW
    GPIO.output(10, GPIO.LOW)

def imgCrop(im):
        box = (0, 150, 640, 200)
        region = im.crop(box)
        region.save('crop.jpg')
    return region

def imgThres(im):
        gray = im.convert('L')
        bw = gray.point(lambda x: 0 if x<50 else 255, '1')
        bw.save("bw.jpg")
    return bw

def find_centroid(im, rez):
        width, height = im.size
        XX, YY, count = 0, 0, 0
        for x in xrange(0, width, rez):
            for y in xrange(0, height, rez):
                    if im.getpixel((x, y)) == 255:
                        XX += x
                        YY += y
                        count += 1
        return XX/count, YY/count

def camera ():
    cam = VideoCapture(0)   # 0 -> index of camera
    Img = cam.read()
    cImg = imgCrop(Img)
    tImg = imgThres(cImg)
    print find_centroid(tImg, 1)

def robo_direct():
        cen = find_centroid(tImg, 1)
        diff = cen[0] - 320
        if diff > 10:
        right()
            print 'right'
        if diff < -10:
        left()
            print 'left'
        else:
        forward()
            print 'straight'



####---------------------------------------------------------------------------------####

forward()
while True:
    camera ()
    robo_direct()

Answer 1

VideoCapture.read doesn't return an image. As listed in the documentation, it returns a retval, image tuple. Dunno what the retval is, but that's your problem.

---

im is a tuple. Tuples don't have a crop method. If im isn't supposed to be a tuple, look at where this function is called from and figure out why it's being passed a tuple.

Also, you have mixed tabs and spaces for indentation. That may or may not be causing problems right now, but it's guaranteed to be a headache at some point. Switch to all tabs or all spaces; PEP 8 recommends all spaces.