# Contrast Guiding Application - Using the Color Contrast Between Two Features

> A Very Special Option for Contrast Guiding and Monitoring So far we have discussed using the negative space between straight edge labels to mimic an intermittent line and also using the edge of a label or contrast as a feature to track. Negative spaces tend to provide most of the opportunities fo...

**Last updated:** 2021-12-08

**Source:** https://live-roll2roll.pantheonsite.io/blog/contrast-guiding-application-using-color-contrast-between-two-features

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A Very Special Option for Contrast Guiding and Monitoring



So far we have discussed using the negative space between straight edge labels to mimic an intermittent line and also using the edge of a label or contrast as a feature to track. Negative spaces tend to provide most of the opportunities for such applications, but we have seen that there are situations where the edge of a contrast can be used, as long as that contrast is constant.



However, there is a condition in contrast monitoring where a special application can be used.



The [SCU5 Controller](https://r2r.tech/products/roll-2-roll-controller) can be taught to track the threshold of two contrasting features. The condition is that each feature has to have a constant color and the orientation of the colors or contrast must also be constant.



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Figure 1.- Color contrasts in different order




 As an example, let’s look at the two images above. Both have a sequence of red, black and yellow. However, the order differs between both. In the right image, the order from left to right is red, black and yellow. In the left image, the order from left to right is yellow, black and red. If we have set our controller to follow the threshold of the black and yellow on the left image, it would not track the threshold of the yellow and black on the right image, because it is in the wrong order. This special feature has limited uses, but is very useful in those limited applications.



As in previous set ups for contrast applications, you will need to access the advanced sensor setting screen to teach the controller. Figure 2 shows the application selected on the advanced sensor screen during the teaching mode. 



![](https://lh6.googleusercontent.com/oKGNw7ZiIHEJmApjNn4z6O185ckZvtX_50HMUBuhLsXa_DSVsqrE4FDMFgdGiSoDN_w6l256LXHCKntbhLv7MMlkZPRbTpa9zLjm_5cLr6kD6YcD2OcbHPioT1SgmCCoiL7KovMV)



Figure 2. Advanced Sensor Setting Screen



![](https://lh3.googleusercontent.com/V_fm47cZmU4zjaPfdVEBtjeZCmcoeMN6Ja72upHM6tzE1-LldQZKNq-v65Vzu4OW1Uy2esnYPDLbl53JixcuAOjtl5-TsyGTyRrssnojlJf2zSQLb4S72wi3RKEHKNRiS4C7Ump2)



Figure 3.- Advanced Sensor Setting Screen Set for Two Contrast Tracking



Additionally, as in previous posts, the feature selected will be highlighted in green on the top bar. The selection of the feature is done by changing the position of the highlight through the arrows on the top.



This application is useful when there are multiple contrast arrangements that can have the same colors available but in different order. Again, it is a very special application that is available to converters. 




 If you have a special contrast application that seems not to have a solution, [contact us and we will help you out](https://r2r.tech/contact).

## Related Products

- Web Guides
- Web Position Sensor
- Web Guide Controller
- SCU5
- ODC 48
- ODC 192

**Tags:** Web Guides, Web Position Sensor, Web Guide Controller, SCU5, ODC 48, ODC 192

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## About Roll-2-Roll Technologies

Roll-2-Roll Technologies designs and manufactures patented fiber-optic web position sensors and advanced web guiding controllers — the precision measurement and control core of modern roll-to-roll manufacturing. Spun out of Oklahoma State University's Web Handling Research Center and trusted by Fortune 500 medical, battery, and nonwovens manufacturers, our patented sensors work without recalibration at ±0.1mm accuracy up to 760 mpm — typical customer outcomes are 50%+ less downtime and payback under six months. Headquartered in Stillwater, Oklahoma, our team of PhDs, controls engineers, and industry veterans extends the sensor + controller core into complete web guide systems including stepper-motor-based linear actuators (RLA, BLA, LHS).

- Website: https://r2r.tech
- Phone: +1 (888) 290-3215
- Email: sales@r2r.tech