Portable system for analyzing human gait

• US 6,836,744 B1
• Filed: 08/17/2001
• Issued: 12/28/2004
• Est. Priority Date: 08/18/2000
• Status: Expired due to Term

• Current Assignee: Advanced Motion Technologies, Inc.
• Original Assignee: Fareid A. Asphahani
• Inventors: Lee, Hwa C., Asphahani, Fareid A.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): Charioui, Mohamed
• Application Number:
  US09/931,040
• Time in Patent Office: 1,229 Days
• Field of Search: 702/47, 702/54-57, 702/98, 702/101, 702/122, 702/138, 702/141-147, 702/151, 702/153, 702/160, 702/173, 702/179, 735/10, 738/654, 36/115, 377/24.2, 494/28
• US Class Current: 702/141
• CPC Class Codes: A43D 1/02 Foot-measuring devices measuring the shape, pattern or size of the body for diagnostic purposes A61B5/103, e.g. measuring physical dimensions A61B5/107
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A63B 2230/62 posture
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: G01G 19/44 for weighing persons
• CPC Class Codes: G01G 19/52 Weighing apparatus combined with other objects, e.g. furniture with walking sticks A45B3/08
• CPC Class Codes: G01P 15/00 Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00

Abstract

The invention is a portable gait analyzer comprising of at least one independent rear foot motion collection unit, at least one independent lower shank motion collection unit, plantar pressure collection unit, at least one processing and display unit, and a soft casing unit. A plurality of accelerometers, rate sensors, force sensor resistors, and pressure sensors provide for the acquisition of acceleration signals, angular velocity signals, foot force signals, and foot pressure signals to be processed. At least one central processing unit, a plurality of memory components, input/output components and ports, telemetry components, calibration components, liquid crystal displays components for the processing and outputting of three dimensional acceleration, angular velocity, tilt, and position. The rearfoot motion collection unit and lower shank motion collection unit interact with the processing and display unit to calculate rear foot kinematic data crucial to identify the motions of pronation and supination. The plantar pressure collection unit interacts with the processing and display unit to calculate plantar pressure data crucial to identify the center of pressure line and excessive and abnormal loads on the sole of the foot. These factors of rear-foot kinematics and plantar pressure lead to gait style identification.

Claims

1. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a) a detachable sole;

b) a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot;

c) a plantar pressure collecting unit positioned between a plantar side of said user'"'"'s foot and the detachable sole;

d) a rearfoot motion collection unit having at least one accelerometer sensor and at least one rate sensor;

e) a lower shank motion collection unit having at least one accelerometer sensor and at least one rate sensor;

f) a detachable processing unit in electrical communication with the plantar pressure collection unit, the rearfoot motion collection unit, and the lower shank motion collection unit, said detachable processing unit for processing data from a plurality of said accelerometers and said sensors; and

g) a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

2. The portable human gait analysis apparatus of claim 1, wherein the data from the central processing unit passes through an I/O unit to a telemetry unit for transfer to at least one of a PC and PDA, for storage and further analysis.

3. The portable human gait analysis apparatus of claim 2, wherein the data from the telemetry unit is transferred to at least one of:

a walkman, a TV, a VCR, a DVD player, a CD player, a projection unit, a game console, a stereo and an internet site for entertainment purposes.

4. The portable human gait analysis apparatus of claim 1, wherein said soft casing unit is sized to fit within a user'"'"'s shoe, with the rearfoot motion collection unit, the lower shank motion unit, and the processing and display unit attached to the outer portion of the user'"'"'s shoe.

5. The portable human gait analysis apparatus of claim 1, wherein independent measurements are taken for said user'"'"'s right foot and left foot, and said processing and display units function independently of each foot.

6. The portable human gait analysis apparatus of claim 1, wherein past data is stored in memory, and processed by the central processing unit for comparison between use.

7. The portable human gait analysis apparatus of claim 1, wherein the display unit is LCD display unit.

8. The portable human gait analysis apparatus of claim 1, wherein the central processing unit processes data from the plurality of accelerometers and sensors to determine pronation, supination and normal data based upon data received from the rearfoot motion collection unit and lower shank motion collection unit.

9. The portable human gait analysis apparatus of claim 1, wherein a user'"'"'s body weight is calibrated by the central processing unit to provide a baseline for processing data.

10. The portable human gait analysis apparatus of claim 1, wherein the detachable sole is flexible, durable, electrically insulating, and resilient.

11. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a) a detachable sole which is flexible, durable, electrically insulating, and resilient;

b) a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot;

c) a plantar pressure collection unit positioned between a plantar side of said users foot and the detachable sole, to identify the center of pressure line and excessive and abnormal loads on the sole of the foot;

d) a rearfoot motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to calculate rearfoot kinematic data crucial to identify the motions of pronation and supination;

e) a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, which when combined with data from the rearfoot kinematic data, to provide three dimensional static and dynamic acceleration, angular velocity, two-axis tilt information, and static and dynamic foot movements;

f) a detachable processing unit in electrical communication with the plantar pressure collection unit, the rearfoot motion collection unit, and the lower shank motion collection unit, said detachable processing unit for processing data from said accelerometers and said plurality of sensors; and

g) a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

12. The portable human gait analysis apparatus of claim 11, wherein the data from the central processing unit passes through an I/O unit to a telemetry unit for transfer to at least one of a PC and PDA, for storage and further analysis.

13. The portable human gait apparatus of claim 12, wherein the data from the telemetry unit is transferred to at least one of:

a walkman, a TV, a VCR, a DVD player, a CD player, a projection unit, a game console, a stereo and an internet site for entertainment purposes.

14. The portable human gait analysis apparatus of claim 11, wherein the plantar pressure collection unit positions force sensor resistors and pressure sensors along a first phalange, a second phalange, a third phalange, a fourth phalange in the forefoot, along a first metatarsal head, a second metatarsal head, and a fourth metatarsal head in the forefoot, along a first metatarsal base, a fourth metatarsal base and a fifth metatarsal base in the midfoot, underneath a distal portion of a medial and lateral side of a calcaneus in the midfoot, and at the medial and lateral surfaces of the calcaneus in the rearfoot, to provide accurate measurement of maximum pressure, mean pressure, and the center of pressure line.

15. The portable human gait analysis apparatus of claim 11 wherein the information displayed on the processing and display unit comprises vital gait information, including over-pronate, supinate, and neutral plantar pressure distribution and the amount of eversion/inversion angle.

16. The portable human gait analysis apparatus of claim 11, wherein the processing and display unit provides a color coded mapping data, which has been normalized by body weight calibration.

17. The portable human gait analysis apparatus of claim 11, wherein said soft casing unit is sized to fit within a user'"'"'s shoe, with the rearfoot motion collection unit, the lower shank motion unit, and the processing and display unit attached to the outer portion of the user'"'"'s shoe.

18. The portable human gait analysis apparatus of claim 11, wherein independent measurements are taken for said user'"'"'s right foot and left foot, and said processing and display units function independently of each foot.

19. The portable human gait analysis apparatus of claim 11, wherein past and current data is stored in memory, and processed by the central processing unit for comparison between use.

20. The portable human gait analysis apparatus of claim 11, wherein the display unit is a LCD display unit.

21. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a) a detachable sole which is flexible, durable, electrically insulating, and resilient;

b) a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot;

c) a plantar pressure collection unit positioned between a plantar side of said user'"'"'s foot and the detachable sole, to identify the center of pressure line and excessive and abnormal loads on the sole of the foot;

d) a rearfoot motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to calculate rearfoot kinematic data crucial to identify the motions of pronation and supination;

e) a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, which when combined with data from the rearfoot kinematic data, provides three dimensional static and dynamic acceleration, angular velocity, 2-axis tilt information, and static and dynamic foot movements;

f) a detachable processing unit in electrical communication with the plantar pressure collection unit, the rearfoot motion collection unit, and the lower shank motion collection unit, said detachable processing unit for processing data from said accelerometers and said plurality of sensors, which has been normalized by body weight and calibration; and

g) an LCD visual display unit in electrical communication with the detachable processing unit for displaying the data comprises vital gait information, including over-pronate, supinate, and neutral plantar pressure/distribution and the amount of eversion/inversion angle of the user'"'"'s foot.

22. The portable human gait analysis apparatus of claim 21, wherein the plantar pressure collection unit positions force sensor resistors and pressure sensors along a first phalange, a second phalange, a third phalange, a fourth phalange in the forefoot, along a first metatarsal head, a second metatarsal head, and a fourth metatarsal head in the forefoot, along a first metatarsal base, a fourth metatarsal base and a fifth metatarsal base in the midfoot, underneath a distal portion of a medial and a lateral side of a calcaneus in the midfoot, and at the medial and lateral surfaces of the calcaneus in the rearfoot, to provide accurate measurement of maximum pressure, mean pressure, and pressure line.

23. The portable human gait analysis of claim 21, wherein independent measurements are taken for said user'"'"'s right foot and left foot, and said processing and display units function independently for each foot.

24. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a plantar pressure collection unit positioned between a plantar side of the user'"'"'s foot and the detachable sole, to identify the center of pressure line and excessive and abnormal loads on the sole of the foot, a detachable processing unit in electrical communication with the plantar pressure collection unit, said detachable processing unit for processing data from said plantar pressure collection unit, said data being normalized by body weight calibration, and an LCD visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit, and the information displayed comprising vital gait information comprising over-pronate, supinate, and neutral plantar pressure/distribution and the amount of eversion/inversion angle of the user'"'"'s foot.

25. The portable human gait analysis apparatus of claim 24 further comprising a rearfoot motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to calculate rearfoot kinematic data crucial to identify the motions of pronation and supination, said detachable processing unit further being in electrical communication with the rearfoot motion collection unit and being further configured for processing said rearfoot kinematic data from said at least one accelerometer sensor and said plurality of rate sensors, said rearfoot kinematic data further being normalized by body weight calibration.

26. The portable human gait analysis apparatus of claim 24 further comprising a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, said detachable processing unit further being in electrical communication with the lower shank motion collection unit and further configured for processing said lower shank motion data from said at least one accelerometer sensor and said plurality of rate sensors, said lower shank motion data further being normalized by body weight calibration.

27. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a rearfoot motion collection unit having at least one accelerometer sensor and at least one rate sensor, a detachable processing unit in electrical communication with the rearfoot motion collection unit, said detachable processing unit being configured for processing data from said at least one accelerometer sensor and said at least one rate sensor, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

28. The portable human gait analysis apparatus of claim 27 further comprising a lower shank motion collection unit having at least one accelerometer sensor and at least one rate sensor, said detachable processing unit being further in electrical communication with said lower shank motion collection unit and being further configured for processing data from said at least one accelerometer sensor and said at least one rate sensor of said lower shank motion collection unit.

29. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a plantar pressure collection unit positioned between a plantar side of said user'"'"'s foot and the detachable sole, to identify the center of pressure line and excessive and abnormal loads on the sole of the foot, a detachable processing unit in electrical communication with the plantar pressure collection unit, said detachable processing unit being configured for processing data from said plantar pressure collection unit, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit, a rearfoot motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to calculate rearfoot kinematic data crucial to identify the motions of pronation and supination, said detachable processing unit further being in electrical communication with the rearfoot motion collection unit, said detachable processing unit being further configured for processing data from said at least one accelerometer sensor and said plurality of rate sensors.

30. The portable human gait analysis apparatus of claim 29 further comprising a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, said detachable processing unit further being in electrical communication with the lower shank motion collection unit and further being configured for processing said lower shank motion data from said at least one accelerometer sensor and said plurality of rate sensors.

31. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a rearfoot motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to calculate rearfoot kinematic data crucial to identify the motions of pronation and supination, a detachable processing unit in electrical communication with the rearfoot motion collection unit, said detachable processing unit being configured for processing said rearfoot kinematic data from said at least one accelerometer sensor and said plurality of rate sensors, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

32. The portable human gait analysis apparatus of claim 31 further comprising a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, which when combined with data from the rearfoot kinematic data, to provide three dimensional static and dynamic acceleration, angular velocity, 2-axis tilt information, and static and dynamic foot movements, said detachable processing unit further being in electrical communication with the lower shank motion collection unit and configured for processing said lower shank motion data from said at least one accelerometer sensor and said plurality of rate sensors from said lower shank motion collection unit.

33. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a rearfoot motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to calculate rearfoot kinematic data crucial to identify the motions of pronation and supination, a detachable processing unit in electrical communication with the rearfoot motion collection unit, said detachable processing unit configured for processing said rearfoot kinematic data from said at least one accelerometer sensor and said plurality of rate sensors, which have been normalized by body weight calibration, and an LCD visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit, and the information displayed comprising vital gait information comprising over-pronate, supinate, and neutral plantar pressure/distribution and the amount of eversion/inversion angle of the user'"'"'s foot.

34. The portable human gait analysis apparatus of claim 33 further comprising a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, which when combined with data from the rearfoot kinematic data, provides three dimensional static and dynamic acceleration, angular velocity, 2-axis tilt information, and static and dynamic foot movements, said detachable processing unit further being in electrical communication with the lower shank motion collection unit and further configured for processing said lower shank motion data from said at least one accelerometer sensor and said plurality of rate sensors of said lower shank motion collection unit, which have been further normalized by body weight calibration.

35. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a plantar pressure collection unit positioned between a plantar side of said user'"'"'s foot and the detachable sole, a rearfoot motion collection unit having at least one accelerometer sensor and at least one rate sensor, a detachable processing unit in electrical communication with the plantar pressure collection unit, said detachable processing unit being configured for processing data from the plantar pressure collection unit, said detachable processing unit further being in electrical communication with said rearfoot motion collection unit, said processing unit being further configured for processing data from at least one accelerometer sensor and said at least one rate sensor, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

36. The portable human gait analysis apparatus of claim 35 further comprising a lower shank motion collection unit having at least one accelerometer sensor and at least one rate sensor, said detachable processing unit further being in electrical communication with said lower shank collection unit and further being configured for processing data from said at least one accelerometer sensor and said at least one rate senor.

37. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a lower shank motion collection unit having at least one accelerometer senor and at least one rate senor, a detachable processing unit in electrical communication with the lower shank motion collection unit, said detachable processing unit being configured for processing data from said at least one accelerometer and said at least one rate senor, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

38. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, a detachable processing unit in electrical communication with the lower shank motion collection unit, said detachable processing unit being configured for processing said lower shank motion data from said at least one accelerometer sensor and said plurality of rate sensors, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

39. A portable human gait analysis apparatus for releasable securement about the user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank over, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a lower shank motion collection unit having at least one accelerometer sensor and a plurality of rate sensors to provide lower shank motion data, a detachable processing unit in electrical communication within the lower shank motion collection unit, said detachable processing unit being configured for processing said lower shank motion data from said at least one accelerometer sensor and said plurality of rate sensors, which have been normalized by body weight calibration, and an LCD visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit, and the information displayed comprising over-pronate, supinate, and neutral plantar pressure/distribution and the amount of eversion/inversion angle of the user'"'"'s foot.

40. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a plantar pressure collection unit positioned between a plantar side of said user'"'"'s foot and the detachable sole, said plantar pressure collection unit having four sensor resistors and pressure sensors along a first phalange, a second phalange, a third phalange, a fourth phalange in the forefoot, along a first metatarsal head, a second metatarsal head and a fourth metatarsal head in the forefoot, along a first metatarsal base, a fourth metatarsal base and a fifth metatarsal base in the midfoot, underneath a distal portion of a medial and lateral side of a calcaneus in the midfoot, and at the medial and lateral surfaces of a calcaneus in the rearfoot, to provide accurate measurement of maximum pressure, mean pressure, and the center of pressure line, a detachable processing unit in electrical communication with the plantar pressure collection unit, said detachable processing unit being configured for processing data from the plantar pressure collection unit, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.

41. A portable human gait analysis apparatus for releasable securement about a user'"'"'s foot, wherein the apparatus comprises:

a detachable sole which is flexible, durable, electrically insulating, and resilient, a soft casing unit having a detachable sole cover, a detachable foot cover, a detachable shank cover, and a releasable securement means for releasably and adjustably securing the detachable sole cover, the detachable foot cover, and the detachable shank cover about said user'"'"'s foot, a plantar pressure collection unit positioned between a plantar side of said user'"'"'s foot and the detachable sole, to identify the center of pressure line and excessive and abnormal loads on the sole of the foot, said plantar pressure collection unit having four sensor resistors and pressure sensors along a first phalange, a second phalange, a third phalange, a fourth phalange in the forefoot, along a first metatarsal head, a second metatarsal head and a fourth metatarsal head in the forefoot, along a first metatarsal base, a fourth metatarsal base and a fifth metatarsal base in the midfoot, underneath a distal portion of a medial and lateral side of a calcaneus in the midfoot, and at the medial and lateral surfaces of a calcaneus in the rearfoot, to provide accurate measurement of maximum pressure, mean pressure, and the center of pressure line, a detachable processing unit in electrical communication with the plantar pressure collection unit, said detachable processing unit being configured for processing data from said plantar pressure collection unit, and a visual display unit in electrical communication with the detachable processing unit for displaying the data processed by the processing unit.