We Keep Coding

Crop bunch of images in a directory in python open cv

I have a bunch of images say 200 in a folder I want to crop all of them. I know the logic to loop through the images in the folder and perform cropping. I wrote a code for cropping of the single image but for multiple images, when I tried to loop through them it showing error.
This is for the single image. This is working fine
import numpy as np
import cv2
import os
count=0
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
img = cv2.imread('C:\\Users\\Sasidhar Mankala\\Desktop\\pythonproject\\DataBase creation\\Images\\85.png')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h+8, x:x+w+8]
crop = img[y-8: y+h+8 , x-8: x+w+8]
image_name = str(count)+'.png'
image_path = os.path.join('C:\\Users\\Sasidhar Mankala\\Desktop\\pythonproject\\DataBase creation\\Cropped_Images',image_name)
count += 1
cv2.imwrite(image_path,crop)
cv2.waitKey(0)
cv2.destroyAllWindows()
For the multiple images, I got this far but this growing error
import numpy as np
import cv2
import os
count=0
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default.xml')
directory = 'C:\\Users\\Sasidhar Mankala\\Desktop\\pythonproject\\DataBase creation\\Images'
for images in directory:
gray = cv2.cvtColor(images, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
# img = cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = images[y:y+h+8, x:x+w+8]
crop = images[y-8: y+h+8 , x-8: x+w+8]
image_name = str(count)+'.png'
image_path = os.path.join('C:\\Users\\Sasidhar Mankala\\Desktop\\pythonproject\\DataBase creation\\Cropped_Images',image_name)
count += 1
cv2.imwrite(image_path,crop)
cv2.waitKey(0)
cv2.destroyAllWindows()
the error showing is
Traceback (most recent call last):
File "c:\Users\Sasidhar Mankala\Desktop\pythonproject\DataBase creation\crop.py", line 11, in
gray = cv2.cvtColor(images, cv2.COLOR_BGR2GRAY)
TypeError: Expected Ptr<cv::UMat> for argument 'src'
I think this is happening is because of cvtColor is expecting a specific path but I don't understand how to do that.
Please help me with this. Thanks in advance

You've to iterate on the images in your directory (feel free to substitute jpg if you have another format
import glob
for images in glob.glob(''.join([directory, r"\*.jpg"])):
# Your code...
In your previous code you were iterating over a string

The problem is this line
for images in directory:
You are not getting the path for each image.
To get the path for each image do:
import os
path_to_images = 'C:/Users/Sasidhar Mankala/Desktop/pythonproject/DataBase reation/Images/'
for imgName in os.listdir(path_to_images):
imgPath = path_to_images + imgName
os.listdir(directory) returns a list of all the filenames in that directory
Another error is in the input to cvtColor. It takes an image input not an image path. So:
image = cv2.imread(imgPath)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
You were also trying to manipulate a path. Notice how in roi_color now is using the imported image and in your code it was trying to use what was supposed to be the image path (images).
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
# img = cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = image[y:y+h+8, x:x+w+8]
crop = image[y-8: y+h+8 , x-8: x+w+8]
image_name = str(count)+'.png'
image_path = os.path.join('C:\\Users\\Sasidhar Mankala\\Desktop\\pythonproject\\DataBase creation\\Cropped_Images',image_name)
count += 1
cv2.imwrite(image_path,crop)
cv2.waitKey(0)
cv2.destroyAllWindows()

How to recognize head movement in open CV?

Good afternoon, I currently have some code which detects eyes and faces using haar cascades, I was curious to see if anybody knows how to get the program to recognize movement of the head e..g. nod or movement of the eye e.g. blink.
Here is what i currently have:
import cv2
import numpy as np
"""
Created on Mon Mar 2 11:38:49 2020
#author: bradl
"""
# Open Camera
camera = cv2.VideoCapture(0)
camera.set(10, 200)
face_cascade = cv2.CascadeClassifier('haarcascades/face.xml')
##smile = cv2.CascadeClassifier('haarcascades/smile.xml')
eye_cascade = cv2.CascadeClassifier('haarcascades/eye.xml')
while True:
ret, img = camera.read()
## converts to gray
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
## determines what a face is and how it is found
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
## Determines the starting and ending co-ordinates for a blue rectangle to be drawn around the face
cv2.rectangle (img, (x,y), (x+w, y+h), (255,0,0), 2)
## Declares the region of the image where the eyes will be
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
## Determines what an eye is based on the eye haar cascade xml file
eyes = eye_cascade.detectMultiScale(roi_gray)
for (ex,ey,ew,eh) in eyes:
##Draws green rectangles around the co-ordintates for eyes
cv2.rectangle(roi_color, (ex, ey),(ex+ew,ey+eh), (0,255,0),2)
##Displays camera
cv2.imshow('Image',img)
##Requires the user to press escape to exit the program
k = cv2.waitKey(40)
if k == 27:
break
Does anybody have any ideas to get the program to recognize head or eye movement?

There are a number of ways to detect eye blinking.
In the ROI of the eyes apply white color detection.
Draw contours of around this mask, if the area of the contour is above a threshold you can interpret the eye is open, whenever there is a sudden change in the area of the contour, that is the point of a blink.
This method would fail if you move towards and away from the camera.
Another way of doing this would be face landmark detection using a library like DLIB.

recognize my face opencv python3

I do some research in this forum and i hope nobody asked the same question.
For my school project i'm trying to create a python program in my raspberry pi 3 for detect face and for recognize my own face. I can detect face but i don't how can i do for recognize my face and write my name in the screen when the camera see me.
Should i create a xml cascade with photos of me ?
Here is my code for detect face :
import numpy as np
import cv2
face_cascade = cv2.CascadeClassifier('face_haar.xml')
cap = cv2.VideoCapture(1)
while 1:
ret, img = cap.read()
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
cv2.imshow('img',img)
k = cv2.waitKey(30) & 0xff
if k == 27:
break
cap.release()
cv2.destroyAllWindows()
This is my first thread in this forum if i do something wrong i'm sorry and say me what i do wrong. If my english is bad i'm sorry and say me if it's true.

How can i get array from 'imshow()' in opencv?

I use opencv to open a camera, it shows face area croping in another window at once, so i have 2 windows in the same time. So i would like to show image and get array at once. Below is my script
import numpy as np
import cv2
# load clasifier from file
face_cascade = cv2.CascadeClassifier('cascades\haarcascade_frontalface_default.xml')
img = cv2.VideoCapture(0)
while(1):
#Read images
h,f=img.read()
gray = cv2.cvtColor(f, cv2.COLOR_BGR2GRAY)
faces = face_cascade.detectMultiScale(gray, 1.3, 5)
for (x,y,w,h) in faces:
# create rectangle
cv2.rectangle(f,(x,y),(x+w,y+h),(255,255,255),)
# crop face area
roi_gray = gray[y:y+h, x:x+w]
# showing crop face area
cv2.imshow('crop',roi_gray)
#create window camera which name is img
cv2.imshow('img',f)
key = cv2.waitKey(200)
if key in [27, ord('Q'), ord('q')]:
break
How to get array from cv2.imshow('crop',roi_gray)? Thank you

Count number of detections with OpenCV lib with Python

I have started to learn OpenCV lib in Python. I want to write a code that will detect faces and eyes on the photo but also count number of detections.
I have wrote a picture that has 6 people on it.
You can download the image form here:
https://www.sendspace.com/file/cznbqa
I wrote a code that detect faces and eyes, but I do not know how to count number of detections.
Also, my code detect 4/8 faces and 1/12 eyes on the photo so...I probably have some issues in the code, If you can help me with that also, I would be very thankful.
# Standard imports
import cv2
import numpy as np
# Read image
my_image = cv2.imread("ljudi.jpg", 1)
# data for detecting faces and eyes
face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_alt.xml')
eye_cascade = cv2.CascadeClassifier('haarcascade_eye.xml')
img = cv2.imread("ljudi.jpg", 1)
gray = cv2.cvtColor(img, 0)
faces = face_cascade.detectMultiScale(gray, 1.2, 4)
for (x,y,w,h) in faces:
#detect face with bule rectangle
#rec. start point (x,y), rec. end point (x+w, y+h), blue color(255,0,0), line width 2
face_rec = cv2.rectangle(img, (x,y), (x+w, y+h), (255,0,0), 1)
roi_gray = gray[y:y+h, x:x+w]
roi_color = img[y:y+h, x:x+w]
eyes = eye_cascade.detectMultiScale(roi_gray, 1.1, 2)
for (ex,ey,ew,eh) in eyes:
eye_rec = cv2.rectangle(roi_color, (ex,ey), (ex+ew, ey+eh), (0,255,0), )
cv2.imshow('img', img)
cv2.waitKey(0)

From the OpenCV documentation:
https://www.docs.opencv.org/2.4/modules/objdetect/doc/cascade_classification.html#cascadeclassifier-detectmultiscale
Detects objects of different sizes in the input image. The detected objects are returned as a list of rectangles.
where a rectangle for the Python bindings simply seems to be of type list [x,y,w,h] (https://www.docs.opencv.org/2.4/modules/core/doc/basic_structures.html#rect).
To the number of faces / rectangles returned inside the list can easily be retrieved by getting the length of the list (i.e. number of items inside), which is done with the Python builtin function len(): https://docs.python.org/3/library/functions.html#len.