Apparatus and method for visualizing periodic motions in mechanical components
A non-contacting system for visualizing and analyzing periodic movements in machinery includes at least one video acquisition device that acquires sampling data as a video comprising a plurality of video image frames and a data analysis system including processor and memory, and a computer program operating in the processor to filter movements depicted in the video to a specific frequency to normalize the phase in a plurality of objects in the video representing parts or components of the machinery, to compare the movements of such objects which in some embodiments provides for construction of a modified video to visually exaggerate the apparent movement of the at least one of the plurality of objects.
1. A system for evaluating a moving object undergoing periodic motion, the system comprising:
at least one video acquisition device that acquires video image files of the moving object;
a processor configured to cause the video acquisition device to acquire sampling data, wherein the sampling data comprises a video recording of a scene having a plurality of image frames of the moving object, wherein an image frame is divisible into a plurality of pixels; and
a computer program operating in the processor to:
operate on pixel intensities at a selected frequency of motion present in the video recording, wherein the pixel intensities are characterized by changes in an intensity of light reflected or transmitted from the moving object, and wherein at least a subset of the changes in intensity of light reflected or transmitted from the moving object are imperceptible to the human eye when viewing an unmodified version of the video recording;
automatically calculate a phase value for one or more pixels at the selected frequency and implement a normalizing phase adjustment, wherein the normalizing phase adjustment is dependent on a direction of displacement of the moving object; and
display phase values in a modified video recording, wherein a plurality of the one or more pixels at the selected frequency represent the normalized phase adjustment by using a directional gradient operator to determine and show a direction of motion of at least one edge of the moving object relative to at least two axes.
2. The system of claim 1 , wherein a normalized phase map is applied to one or more frames of the video as it is replayed based on at least one of the plurality of image frames as selected by the user.
3. The system of claim 2 , wherein the moving object comprises a plurality of components, and the one or more normalized phase values is calculated for a subset of the pixels in the field of view as defined by the user using a graphical user interface.
4. The system of claim 2 , wherein the computer program further operates to provide a modified version of the video recording as it is replayed, wherein the modified version produces motion amplification of the displacement of the moving object, wherein the motion amplification is performed digitally to visually exaggerate apparent movement of the at least one object.
5. The system of claim 1 , wherein one or more normalized phase vectors is shown on at least one of the plurality of image frames for a position in the field of view identified by the user.
6. The system of claim 1 , wherein one or more normalized phase values is labeled on at least one of the plurality of image frames for a position in the field of view identified by the user.
7. The system of claim 1 , wherein the normalizing phase adjustment also is dependent on a direction of contrast between the moving object and at least one other structure in the scene.
8. The system of claim 1 , wherein the directional gradient operator is a Sobel operator, and wherein the computer program further operates to determine a position of the at least one edge by canny edge detection.
9. The system of claim 1 , wherein the normalized phase adjustment changes at least a subset of pixels on the image frames to appear black or transparent.
10. A method of visualizing and studying motion of a moving object, comprising:
using a video acquisition device to acquire a video recording of a scene that contains the moving object, wherein the video recording comprises a plurality of image frames of the moving object and wherein an image frame is divisible into a plurality of pixels;
selecting a frequency of motion present in the video recording, wherein the selected motion is characterized by changes in an intensity of light reflected or transmitted from the moving object, and wherein at least a subset of the changes in intensity of light reflected or transmitted from the moving object are imperceptible to the human eye when viewing an unmodified version of the video recording;
automatically performing a normalizing phase adjustment upon measured phase values of pixel intensity by using a directional gradient operator to determine and show in a modified video recording a direction of motion of at least one edge of the moving object relative to at least two axes, and wherein the normalizing phase adjustment is dependent on a direction of displacement of the moving object;
displaying a modified image frame containing the moving object; and
superimposing in the modified video recording at least one modified phase value in which a plurality of pixels represent the normalized phase adjustment associated with the selected frequency of motion.
11. The method of claim 10 , wherein the normalizing phase adjustment is dependent on a direction of contrast between the moving object and at least one other structure in the scene.
12. The method of claim 10 , wherein a normalized phase map is applied to one or more frames of the recorded video as it is replayed based on at least one of the plurality of image frames as selected by the user.
13. The method of claim 10 , wherein one or more normalized phase vectors is shown on at least one of the plurality of image frames for a position in the field of view identified by the user.
14. The method of claim 10 , wherein one or more normalized phase values is labeled on at least one of the plurality of image frames for a position in the field of view identified by the user.
15. The method of claim 10 , wherein the directional gradient operator is a Sobel operator, and wherein the computer program further operates to determine a position of the at least one edge by canny edge detection.
16. The method of claim 10 , wherein the normalized phase adjustment changes at least a subset of pixels on the image frames to appear black or transparent.