Camera Zoom Calibration: Integrated Framer Visualization

This procedure provides guidance for calibrating Canon PowerShot cameras using Wizard’s Integrated Framer® Visualization software. The software can accurately measure project dimensions throughout the camera’s zoom range.
Successfully calibrating the software measurements for the camera zoom points is dependent on several environmental factors, the greatest of which are the ambient lighting conditions and the alignment of the camera with the target that is photographed.

Wizard™ International, Inc. has found that many installation sites have bright and direct overhead lighting. This can result in too much light being reflected from the target to the camera. Too much light can result in poor calibration (which results in erroneous measurements) or even calibration failure. Several steps can be taken to reduce reflected light when calibration difficulties are encountered. These are:

• Turn off some of the overhead lighting.

• Use side lighting during the calibration process. Side lighting, as from a table lamp, is not reflected directly back to the camera at high enough intensity to interfere with the calibration process.

• Use a #2 lead pencil to “color” the dot at the center of the printed target.

• Spray the printed target with a matte spray (such as Sureguard #931 Photographic Lacquer with UV Inhibitor).

• Adjust the camera exposure compensation to + 1/3 or + 2/3 settings if necessary or to -1/3 or - 2/3.

• Use a photo neutral colored background (such as a neutral gray sheet of matboard - avoid glossy finishes).

The calibration is also dependent on the quality of the camera’s optics (lens). The calibration accuracy cannot exceed the resolution of the image captured by the camera and presented to the software that computes the measurements at each zoom setting. Practice has found that successful measurement calibrations should be within 1/8 inches of the actual measurement of artwork photographed. If a greater variation is observed, the camera zoom setting calibration process should be repeated. Once successfully calibrated, changing the zoom setting should not affect the measurement calibration.

Follow the instructions for Camera Installation if this is a new installation, or if the camera has been moved.

Make sure camera is connected and is turned on.

Start the IF Visualization software.

Click Options on the menu bar.

Click Calibrate Zoom.

IF Visualization detects the camera model and presents a confirmation prompt screen - click the check box for Remember this Camera then OK.

Click Print Target to print the calibration target to the Windows default printer.

Optionally, click Print Target from the options menu.

Take the target from the printer and fill in the circle at the center of the target with a #2 lead pencil.

If experiencing problems getting a good calibration, spray the target with matte spray, which reduces glare from the target and may improve calibration results.

1. Center Target in Camera View

Place the prepared target on the design table immediately under the camera.

Click the Next button on the IF Visualization software screen.

The design table in the IF Visualization viewing frame will display.

Zoom the camera in on the target by sliding the zoom control (move the slider left to zoom out, right to zoom in) and center the “dot” at the center of the target with the crosshairs displayed by the software.

2. Find/Set the Starting Zoom

Slide the zoom control (move the slider left to zoom out, right to zoom in) until the circle just fits within the viewing window. The proper zoom setting is dependent on the distance from the camera to the work surface.

At this time user can adjust the camera’s exposure compensation setting.
Start with zero and adjust later if the calibration process fails - experiment with one step at a time.

Click Next.

3. Execute the Calibration Process

The software now displays the start calibration prompt screen.

Click Calibrate to start the process.

The software starts calibrating the measurements for the camera zoom points.

The software takes a photograph at every third point and computes the proper measurement for each of the zoom points. While the calibration process is running the target is displayed with red and blue lines intersecting at the center of the target.

If one or more snap shots look like any of the examples displayed under examples of bad calibration, the calibration is not going to succeed. Simply wait for the process to complete and start over after adjusting lighting and/or the camera’s exposure compensation. Only change one setting at a time.

4. Examples of Bad Calibration

If any of these images are seen during the calibration process, the lighting and/or camera exposure setting should be adjusted and the calibration process restarted.

Invalid calibration at zoom setting: When the red and blue calibration lines do not line up, an erroneous calibration value will result.

Cannot calibrate at zoom setting: When red and blue, or red, blue and black blobs are displayed there is too much reflected light reaching the camera and a calibration point cannot be established.

No image captured: When a solid black image is displayed no image was captured and a calibration point cannot be established.

Calibration Process Completed

Calibration Successful

When the calibration process completes a curve is displayed showing the results. If this curve is smooth, the calibration process has succeeded.

If this shape curve displays click Finish to complete calibration process.

The next step is to check the measurement for a piece of art to confirm the zoom settings are calibrated correctly.

Calibration Unsuccessful

When the calibration curve is not smooth, some of the zoom setting measurement points did not calculate correctly.

If a curve with outlying points displays, adjust the lighting and/or camera exposure compensation and repeat the calibration process. Only change one setting at a time.

Camera Zoom Calibration Complete

The camera is now calibrated at all zoom points. It will remain calibrated as long as the camera mounting is not physically changed. If the camera mounting is disturbed or if the measurement consistently vary, then repeat this entire procedure.
Proceed to Check Software Measurements.

1. Set Initial Measurement Scale

Click Acquire From Camera button.

Place a ruler or tape measure horizontally across the field of view of the camera on the design table.

Click Take Picture.

Now click Set New Scale and drag a line horizontally from one edge of the ruler to the other.

To draw the line, click and hold the left mouse button at the left edge of the ruler (the zero point) and drag the mouse across the image releasing the mouse button at the right end of the ruler. Take as long of a measurement as possible as this improves the software’s measurements.

A box opens requesting the width measurement - enter the number of inches that was measured in this box (the example below is 24 inches).

Click OK. The initial measurement scale for the default zoom point is now set.

Measure a Piece of Art

Click Acquire From Camera button from Step 1: Load an Image.

Position a piece of art under the camera and center it in the field of view.

Click Take Picture.

Click Next on the acquire image screen.

Click Set Art Region button.

Draw a selection box around the art.

The dimensions of the image displays on the width and height boxes under the set art region button.

The dimensions of the image should be approximately the same as the measurements taken with the ruler, within 1/8 inches. If the dimensions are correct and the image still appears “square,” then the camera is calibrated at this specific fixed zoom point.

3. Set Framing Zoom Point (For Zoom Cameras)

Place a piece of art on the design table immediately under the camera that is slightly larger than the size of the art usually framed. If using mat and frame corner samples with IF Visualization arrange them around the art as normal.

On Step 1: Load an Image click Acquire from Camera. The image of the design table should display, with all the items placed there, displayed in the software image viewer.

Slide the zoom bar (move the slider left to zoom out, right to zoom in) until everything placed on the design table is visible in the software viewer window. This is the zoom point for this project.

To see the zoom level, click on the zoom level slider but don’t move it; the zoom level will be briefly displayed next to the words zoom level above the slider. Notice that the zoom setting can be varied, and when the art region is measured the measurement of the art will be consistently within +/- 1/8 inch of the actual measurement. This is within acceptable tolerances to account for having the lower mat layer slightly overlap the edge of the art image. User will still have to pay attention to these measurements as framing projects are created to insure they are correct and what is intended.

4. Measurements in Retail Management
This is a feature of IF Retail Management.

Complete a test framing project design in IF Visualization.

Click Send to IF-RM from Step 3: Visualize Project.

IF Retail Management will open to the custom ticket screen and display the project from IF Visualization.

Confirm the project dimensions are correct and the same as they were in IF Visualization.

See the Integrated Framer Visualization User Guide for information on making a profile. Please note that if the user makes a color profile using the zoom camera, is it recommended that the user recalibrates the zoom to ensure the software measurements for the zoom are correct.