|
You can report a bug by clicking here, but please check the points below before reporting a bug.
- Set your camera to the highest resolution and the highest quality.
- If possible Setup your camera to Manual mode, with constant aperture (eg : f/8.0) before calibrating and for all shots.
- Calibrate your camera. You must calibrate your camera if you want to use uncoded targets. You will find the detailed procedure in the documentation.
- Check the targets are "readable", the small dimension of center of the target must measure 8 pixels minimum :
 Example of "readable" targets :
 
Example of "Unreadable" targets :
 
- If you use Uncoded targets Stripes. Draw and Print the uncoded circle with same diameter than the Coded Target center.
- Keep always a constant zoom factor (the same one used during the calibration process). You should keep the same zoom factor for the complete series of photos to be used for digitizing.
- Never start your tests on a full complex part. Always try on a partial zone of the part before. This allow to check if the size of the targets are correct and readable. It is not pleasant to discover that targets are too small after to have positioned 2 hundreds of it !
- Avoid digitizing flat surfaces. Do not distribute all the coded target on a single plane surface. The algorithms used do not allow the position of the camera to be calculated if all the points are on a single plane surface.
- Respect a minimum angle between each photo shot. It is important that the angle between two shots is not too small, an angle of less than 15° between two shots made the couple of photo are not used for the 3D reconstruction... Rhinophoto automatically check and decide to use or not a photo.
- Do not edit or modify the photo images before 3D digitizing. Rhinophoto uses the EXIF data stored in the image file to find and load the Camera calibration file. If you load and store your image files with an image processing software, it is possible that the software can modify or delete EXIF data which will result errors during the process.
- The zone where digitizing are to be made must be as big as possible on the photo.
- Take photographs with uniform lighting.
- Always take your photos in one single sequence with the same lighting conditions. This is very important for images to be used for calibration purposes.
- Take more photos than required.Take as many photos as you think is necessary and then take some more ! It is often the case that there is a zone that you want to digitizing that isn't visible on 2 photos.The more photos you have, the better it is.
- Place as many coded target as possible. The quality and the accuracy mainly depend on the 3D position calculation of the camera at the time the photographs were taken.The more coded target there are on the photo, the greater the precision of the 3D position calculation and therefore the digitizing. A minimum number of 8 points on two photos are the minimum required by the algorithms to be able to calculate camera positions. However, this minimum number is highly theoretical because errors can be induced by calculation rounding off.
- Whenever possible, try to correctly distribute these points over as large an area as possible. 'Clustered' or 'in a corner' points distribution will reduce precision
|
|
Last Updated on Thursday, 19 August 2010 09:25 |