Camera stream access with OpenCV in Drone Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to open the default camera stream using OpenCV.

Drone Programming

import cv2

cap = cv2.VideoCapture([1])

if not cap.isOpened():
    print("Cannot open camera")

Drag options to blanks, or click blank then click option'

A"camera"

B1

C0

D-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of 0 for the default camera index.

Passing a string instead of an integer.

The default camera is accessed with index 0 in OpenCV.

2fill in blank

medium

Complete the code to read a frame from the camera stream.

Drone Programming

ret, frame = cap.[1]()

if not ret:
    print("Failed to grab frame")

Drag options to blanks, or click blank then click option'

Acapture

Bread

Cget

Dfetch

Attempts:

3 left

💡 Hint

Common Mistakes

Using get() which only retrieves properties.

Using capture() or fetch() which do not exist.

The read() method captures a frame from the video stream.

3fill in blank

hard

Fix the error in the code to release the camera resource properly.

Drone Programming

cap.[1]()
cv2.destroyAllWindows()

Drag options to blanks, or click blank then click option'

Aclose

Bend

Cstop

Drelease

Attempts:

3 left

💡 Hint

Common Mistakes

Using close() which does not exist for VideoCapture.

Using stop() or end() which are invalid.

The release() method frees the camera resource.

4fill in blank

hard

Fill both blanks to convert the captured frame to grayscale and display it.

Drone Programming

gray = cv2.[1](frame, cv2.[2])
cv2.imshow('Gray Frame', gray)

Drag options to blanks, or click blank then click option'

AcvtColor

BCOLOR_BGR2GRAY

CCOLOR_RGB2GRAY

DconvertColor

Attempts:

3 left

💡 Hint

Common Mistakes

Using convertColor which is not a valid function.

Using COLOR_RGB2GRAY when the frame is in BGR format.

Use cvtColor with COLOR_BGR2GRAY to convert a BGR image to grayscale.

5fill in blank

hard

Fill all three blanks to create a loop that reads frames, shows them, and breaks on pressing 'q'.

Drone Programming

while True:
    ret, frame = cap.[1]()
    if not ret:
        break
    cv2.imshow('Frame', frame)
    if cv2.waitKey([2]) & 0xFF == ord([3]):
        break
cap.release()
cv2.destroyAllWindows()

Drag options to blanks, or click blank then click option'

Aread

B1

C'q'

Dwait

Attempts:

3 left

💡 Hint

Common Mistakes

Using wait() instead of waitKey().

Using a wrong key character or missing quotes around 'q'.

Not breaking the loop properly on key press.

The loop reads frames with read(), waits 1 ms for a key press, and breaks if 'q' is pressed.