March 23, 2010
Brighter is not necessarily better
Tech Help Correspondent John Rivera
We all know the squad-mounted computer screen needs to be easily readable in both daytime and nighttime conditions. What we sometimes forget is that too bright at night can be just as bad as not bright enough in daytime. When you’re responding to a call, it’s critical to get the information you need with just a quick glance at your MDT or laptop computer mounted in your patrol car. We all know that letting your eyes linger on the computer is dangerous. I am now working nights and a bright screen is very bothersome. I typically read the dispatch and close the lid. This way I take the distraction away and I can look out the windshield much better. Also, our computer aided dispatch software allows for a Day/Night mode but it does not affect the other software I have open.
Two of the most popular manufacturers of rugged computers for the law enforcement community are Panasonic Computer Solutions Company and General Dynamics Itronix. Each company’s computers offer ways to handle the problem of screen “readability” in the tactical environment. My agency is currently using the Panasonic Toughbook and we have discovered it is very functional and user friendly. It has an internal antenna and can easily be configured for different uses by adding to or removing hardware from the modular bays.
With the Panasonic machines, cops can immediately turn off all external lights on the computer while it stays running. So if you’re on a stakeout or otherwise trying to be inconspicuous, you just hit a few keys and avoid attracting attention without shutting down. The company issued a press announcement last year that said, in part, that “Toughbook 30 and 19 mobile computers include a ‘concealed mode’ which allows users to easily turn all device lights off — screen and LEDs — using a function (Fn) key, without having to power down the machine. The feature allows users to customize which attributes get turned off when the Fn key is pressed including screen, LEDs, backlit keyboards (my favorite feature), volume, and wireless radios (Wi-Fi, Bluetooth, and mobile broadband). Furthermore, users can select if they wish the screen to be turned off, or just set to the minimum brightness level. The ‘concealed mode’ feature is ideal for military and law enforcement applications and for jurisdictions requiring vehicle-mounted PCs to have their screens turned off while the vehicle is in operation.”
Many screens incorporate display technology that simply increases the display brightness — this is fine if your only problem is cranking the thing up during daylight hours — but you may also want to adjust the “contrast” of the screen to suit the lighting conditions of your shift.
Screen brightness is measured in something called NITs. General Dynamics says that NIT ratings are not an indicator of viewability, and that contrast ratio is a more appropriate measurement of outdoor performance. “High ambient contrast ratio Contrast ratio,” says the company in one of its product sheets, “provides a much clearer characterization of viewability.”
General Dynamics has developed a patent-pending display technology called “DynaVue” which creates optimum outdoor readability by reducing both “specular and diffused reflections.” The company document goes on to say that “DynaVue technology uses polarizing techniques and multi-layer indexed matched coatings to transform the frequency of the reflected light waves and eliminate reflections that make displays unreadable. With DynaVue patent-pending display technology, customers experience rich luminous colors; dark areas appear darker and fine details are more pronounced. And since DynaVue does not require additional brightness, battery life and processor performance are optimized.”
Regardless of which manufacturer made your MDT or notebook, try to find out how you can adjust its brightness and contrast settings for optimal readability as the lighting conditions change throughout your shift.