Unit 4: Robot Vision Sensors - Practice Quiz

1 What is the main purpose of a vision sensor in a robot?

2 Which device is commonly used to capture images in a robotic vision system?

3 What type of information does a 2D vision sensor primarily provide?

4 What additional information does a 3D vision sensor provide compared with a basic 2D sensor?

5 Which connection is commonly used to transfer digital image data from a camera to a computer?

6 Why is a driver often needed when connecting a vision sensor to a computer?

7 What does SLAM stand for in mobile robotics?

8 During SLAM, what does localization mean?

9 What is the main goal of sensor fusion?

10 Which combination is an example of sensor fusion in a robot?

11 What does LiDAR use to measure the distance to objects?

12 What type of output is commonly produced by a 2D LiDAR sensor?

13 What is image acquisition?

14 What does image resolution describe?

15 What is the function of an ADC?

16 What is the function of a DAC?

17 How many main signal lines are normally used by the I2C communication protocol?

18 Which communication protocol commonly uses separate lines for data input and data output?

19 Which setting must usually match between two devices communicating through UART?

20 In ROS, what is commonly used to carry sensor data between software nodes?

21 A robot must detect the color and approximate location of objects on a conveyor belt. Which sensor is most suitable for this task?

22 A camera produces images with noticeable blur when a robot moves quickly. Which adjustment is most likely to reduce motion blur?

23 A warehouse robot needs to determine the height of boxes stacked on a pallet. Which sensing approach is most appropriate?

24 A stereo vision system uses two cameras separated by a baseline. If an object appears with a larger disparity between the two images, what can be inferred?

25 A camera outputs image frames at a rate higher than the robot controller can process. Which interface strategy helps prevent excessive buffering and delay?

26 A vision sensor and robot controller produce inconsistent measurements because their timestamps do not refer to the same clock. What is the best corrective action?

27 During SLAM, a robot revisits a previously observed corridor and recognizes the location. Which SLAM function uses this observation to reduce accumulated drift?

28 A robot uses a depth camera for visual SLAM in an environment with many textureless white walls. Which problem is most likely?

29 An autonomous robot combines wheel odometry with camera measurements. Why is sensor fusion useful in this situation?

30 In a Kalman filter, the measurement noise covariance for a camera is increased because the camera is operating in poor lighting. What effect does this have?

31 A 2D LiDAR mounted on a mobile robot scans at a fixed height. Which limitation should be expected?

32 A LiDAR sensor measures a round-trip laser travel time of . Using , what is the approximate target distance?

33 A camera uses a rolling shutter while a robot arm moves rapidly during image capture. Which distortion may occur?

34 A camera has a focal length and a pixel size of . What is the approximate focal length in pixels?

35 An 8-bit ADC uses a reference. What is its approximate voltage resolution per digital step?

36 A sensor output changes from to , but the ADC reference is set to . What is the main disadvantage?

37 Two I2C devices share the same bus and both attempt to transmit at the same time. What mechanism allows the bus to resolve this situation?

38 A vision sensor must transfer large image data blocks to a controller over a short PCB connection. Which communication method is generally the better choice?

39 A UART receiver reports framing errors when connected to a sensor. Which configuration mismatch is the most likely cause?

40 In ROS, a LiDAR node publishes range scans while a navigation node consumes them. Which communication pattern is most appropriate?

41 A mobile robot uses a camera with a fixed focal length. An object moves from the image center toward the edge while maintaining constant distance from the camera. Which effect most directly explains the increasing geometric error in the estimated position?

42 A robot must estimate the metric distance to a textureless planar wall using a single passive camera. Which additional condition is necessary to make the depth estimate observable?

43 A stereo camera has focal length pixels and baseline m. For a feature with disparity pixels, what is its estimated depth using ?

44 A camera streams frames with hardware timestamps, while the robot controller timestamps received packets. Variable Ethernet delay is present. Which design gives the most reliable temporal alignment with IMU data?

45 A vision sensor outputs 1280 x 720 monochrome images at 60 frames per second with 10-bit pixels. Ignoring protocol overhead, what minimum sustained payload bandwidth is required?

46 In graph-based visual SLAM, loop closure adds a constraint between two previously distant poses. If the loop-closure measurement is incorrect but assigned very high confidence, what is the most likely consequence?

47 A robot performs monocular visual-inertial SLAM while moving with constant velocity along a straight line and observing a distant planar wall. Which observability issue is most concerning?

48 An extended Kalman filter fuses wheel odometry and camera pose measurements. The camera occasionally reports a pose with a covariance that is unrealistically small. What is the most appropriate response?

49 Two sensors measure the same state but their errors are correlated because both depend on the same visual feature extractor. If the fusion algorithm assumes independence, what error is most likely introduced?

50 A time-of-flight LiDAR emits a pulse and receives the reflection after ns. Assuming a direct round trip and propagation at m/s, what range is measured?

51 A LiDAR mounted on a robot reports a wall that appears curved even though the wall is planar. Calibration shows the range values are correct but the angular encoder has a scale error. Which correction is most appropriate?

52 A LiDAR scan is acquired while a robot rotates rapidly. Points from the beginning and end of the scan are transformed using the robot pose at the scan midpoint. What artifact is most likely?

53 A camera captures a rapidly rotating fan using a rolling shutter. The fan blades appear curved and their apparent positions vary across image rows. What is the primary cause?

54 A sensor has full-well capacity electrons and read noise of electrons RMS. Assuming shot noise variance equals the number of collected electrons, at approximately how many electrons are shot noise and read noise equal in magnitude?

55 An ideal 12-bit ADC uses a V reference. What is the approximate voltage resolution per least significant bit?

56 A 10-bit ADC samples a signal containing frequencies up to 7 kHz. Which sampling strategy is required to prevent aliasing under ideal conditions?

57 On an I2C bus, the SDA line remains low after a peripheral resets during a transaction. What recovery action is commonly used before reinitializing the bus controller?

58 An SPI sensor samples data on the rising edge and changes data on the falling edge. Which mode is required if the clock idles low?

59 An I2C bus operates at kbit/s with a total bus capacitance of pF. Why can an excessively large pull-up resistor cause communication failure?

60 A UART link uses 8-N-1 framing at 115200 baud. Ignoring flow-control overhead, what is the maximum payload rate for 8-bit bytes?