Difference between revisions of "How to Calibrate Camera Optics"
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(Created page with "== Introduction == '''Calibration of camera optics''' is required to find out the values of the following parameters: * [https://en.wikipedia.org/wiki/Focal_length Focal leng...") |
(Recording of Calibration Video) |
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{{Note|As to web-cameras usable with '''iPi Motion Capture''' ([http://en.wikipedia.org/wiki/PlayStation_Eye Sony PS3 Eye] and [https://www.logitech.com/en-us/product/c922-pro-stream-webcam Logitech C922]), they have optics with low distortion and principal point shift is not significant as a rule. For this reason camera optics calibration is not required for them. But if you want, you can calibrate them and apply results of this calibration to recorded video using '''Build Combined Video''' tool of [[iPi Recorder]] application.}} | {{Note|As to web-cameras usable with '''iPi Motion Capture''' ([http://en.wikipedia.org/wiki/PlayStation_Eye Sony PS3 Eye] and [https://www.logitech.com/en-us/product/c922-pro-stream-webcam Logitech C922]), they have optics with low distortion and principal point shift is not significant as a rule. For this reason camera optics calibration is not required for them. But if you want, you can calibrate them and apply results of this calibration to recorded video using '''Build Combined Video''' tool of [[iPi Recorder]] application.}} | ||
| − | == Recording of | + | == Recording of Calibration Video == |
| + | * Mark camera by some label to distinguish it from others. | ||
| + | * Set view-angle and resolution you're going to use for motion capture. | ||
| + | * {{Tip|720p (1280 x 720) resolution is recommended for full body motion capture needs in most cases (except very large capture area).}} | ||
| + | * {{Important|If you use [https://shop.gopro.com/cameras GoPro] action camera, please don't use [https://gopro.com/help/articles/question_answer/What-is-SuperView '''SuperView'''] mode because in this mode calibration will fail because of special "dynamic stretches" from 4:3 to 16:9 made by camera software.}} | ||
| + | * If your camera has zoom and/or auto-focus features then these features must be turned off before calibration because this procedure is valid only for fixed optics. | ||
| + | * Run [[iPi Recorder]] and click '''Calibrate Camera Optics''' button in toolbar: | ||
| + | <center>[[Image:camera-calibration-tool-button.png|link=]]</center> | ||
| + | * To calibrate camera optics special calibration pattern is used. You have to record this pattern shown on computer screen from different view points. | ||
| + | * Click '''Show Pattern''' button in toolbar of '''PATTERN''' tab of '''Camera Optics Calibration''' tool: | ||
| + | <center>[[Image:camera-calibration-show-pattern-button.png|link=]]</center> | ||
| + | * | ||
| + | == Processing of Calibration Video == | ||
| − | |||
| − | + | == Results == | |
| − | == Results | + | |
Revision as of 07:16, 1 August 2018
Contents
Introduction
Calibration of camera optics is required to find out the values of the following parameters:
- Focal length
- Shift of camera principal point from the center of image
- Radial distortion parameters (2 — 4 coefficients)
- Pixel aspect ratio (optional)
- Pixel shear (optional)
This procedure is strongly mandatory for modern wide-angle cameras including action cameras. The thing is that these cameras has significant distortion.
Recording of Calibration Video
- Mark camera by some label to distinguish it from others.
- Set view-angle and resolution you're going to use for motion capture.
- Tip: 720p (1280 x 720) resolution is recommended for full body motion capture needs in most cases (except very large capture area).
- If your camera has zoom and/or auto-focus features then these features must be turned off before calibration because this procedure is valid only for fixed optics.
- Run iPi Recorder and click Calibrate Camera Optics button in toolbar:
- To calibrate camera optics special calibration pattern is used. You have to record this pattern shown on computer screen from different view points.
- Click Show Pattern button in toolbar of PATTERN tab of Camera Optics Calibration tool:
