Monthly Archives: October 2017

Key Components of MTF Testing

How can you pick the right MTF company like Before you start your search it helps to know some of the main components of Modulation Transfer Function (MTF) testing. Here are some of them

  1. Contrast

It’s a good idea to normalize the bar target’s intensity by giving it a maximum value to the white bars as well as a zero value to the black bars. When the values are plotted in a square wave the idea of contrast can be seen more easily. When the same idea is applied to imaging samples the intensity pattern before/after the imaging I visible. Contrast/modulation then can be dined by how closely the minimum/maximum intensity values are moved from the object plane to the image plane.

  1. Resolution

This it eh ability of an imaging system to distinguish detail. There are different ways it’s expressed including line-pairs per millimeter or frequency. Inverting the frequency results in the spacing in mm between 2 resolved lines. A good way to test system performance is bar targets that contained a group of white/black bars that are alternating and equally spaced.

In the case of all imaging optics when those patterns are imaged a perfect line edge turns somewhat blurry. High-res images show a big amount of detail that results from little blurring. Meanwhile, images that are low-resolution lack sharp detail.

So the next issue is why MTF is important. In traditional system integration the performance of the system is estimated basically by using the weakest link principle. This proposes that the resolution of the system is only limited by the part with the lowest resolution. The approach is helpful and results in quick calculations it’s not a good option since each component in the system causes error in the image. This results in poorer image quality than just the weakest link.

Each component in a system has a MTF linked to it. As a result, it affects the system’s overall MTF. That includes the camera sensor, imaging lens, video cables, and capture boards. The MTF of a system is the result of the MTF curves of all of the components. For example, the testing of MTF curves of some lenses is very basic in order to determine which combo would result in the best performance. However, that’s not always the case.

This highlights the need to hire the right company to do MTF testing. It’s a very technical process so you’ll certainly want a company with the right equipment and know-how to do the testing for you. This is why it’s critical to make sure you’ve found the right company to handle your MTF testing for lenses. If that’s the case then you’ll be on the right track to getting the right results.

Make sure you’re dealing with the right company to make sure you’re getting the best results. If you find the right company then it’ definitely worthwhile since you can deal with the same company for all your MTF testing. It can be tough to find multiple companies for different kinds of testing and would require more time and effort on your part.

All About Mini-Split Air Conditioners

Ductless, mini split-system air-conditioners (mini splits) have numerous potential applications in residential, commercial, and institutional buildings. The most common applications are in multifamily housing or as retrofit add-ons to houses with “non-ducted” heating systems, such as hydronic (hot water heat), radiant panels, and space heaters (wood, kerosene, propane). They can also be a good choice for room additions and small apartments, where extending or installing distribution ductwork (for a central air-conditioner or heating systems) is not feasible. Like central systems, mini splits by have two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units.


The main advantages of mini splits are their small size and flexibility for zoning or heating and cooling individual rooms. Many models can have as many as four indoor air handling units (for four zones or rooms) connected to one outdoor unit. The number depends on how much heating or cooling is required for the building or each zone (which in turn is affected by how well the building is insulated). Each of the zones will have its own thermostat, so you only need to condition that space when it is occupied, saving energy and money.

Ductless mini split systems are also often easier to install than other types of space conditioning systems. For example, the hook-up between the outdoor and indoor units generally requires only a three-inch (~8 centimeter [cm]) hole through a wall for the conduit. Also, most manufacturers of this type of system can provide a variety of lengths of connecting conduits. So, if necessary, you can locate the outdoor unit as far away as 50 feet (~15 meters [m]) from the indoor evaporator. This makes it possible to cool rooms on the front side of a building house with the compressor in a more advantageous or inconspicuous place on the outside of the building.

Since mini splits have no ducts, they avoid the energy losses associated with ductwork of central forced air systems. Duct losses can account for more than 30% of energy consumption for space conditioning, especially if the ducts are in an unconditioned space such as an attic.

Compared with other add-on systems, mini splits offer more flexibility in interior design options. The indoor air handlers can be suspended from a ceiling, mounted flush into a drop ceiling, or hung on a wall. Floor-standing models are also available. Most indoor units have profiles of about seven inches (~18 cm) deep and usually come with sleek, high-tech-looking jackets. Many also offer a remote control to make it easier to turn the system on and off when it’s positioned high on a wall or suspended from a ceiling. Split-systems can also help to keep your home safer, because there is only a small hole in the wall. Through-the-wall and window mounted room air-conditioners can provide an easy entrance for intruders.


The primary disadvantage of mini splits is their cost. Such systems cost about $1,500 to $2,000 per ton (12,000 Btu per hour) of cooling capacity. This is about 30% more than central systems (not including ductwork) and may cost twice as much as window units of similar capacity.

The installer must also correctly size each indoor unit and judge the best location for its installation. Oversized or incorrectly located air-handlers often result in short-cycling, which wastes energy and does not provide proper temperature or humidity control. Too large a system is also more expensive to buy and operate.

Some people may not like the appearance of the indoor part of the system. While less obtrusive than a window room air conditioner, they seldom have the built-in look of a central system. There must also be a place to drain condensate water near the outdoor unit.

Qualified installers and service people for mini splits may not be easy to find. In addition, most conventional heating and cooling contractors have large investments in tools and training for sheet metal duct systems. They need to use (and charge for) these to earn a return on their investment, so they may not recommend ductless systems except where a ducted system would be difficult for them to install.

All You Need TO Know About Room Air Conditioners

Room or window air conditioners cool rooms rather than the entire home or business. If they provide cooling only where they’re needed, room air conditioners are less expensive to operate than central units, even though their efficiency is generally lower than that of central air conditioners. Smaller room air conditioners (i.e., those drawing less than 7.5 amps of electricity) can be plugged into any 15- or 20-amp, 115-volt household circuit that is not shared with any other major appliances. Larger room air conditioners (i.e., those drawing more than 7.5 amps) need their own dedicated 115-volt circuit. The largest models require a dedicated 230-volt circuit. Companies like can help with your installation.

Energy Efficiency of Room Air Conditioners

A room air conditioner’s efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units [Btu] per hour) to the power input (in watts). The higher the EER rating, the more efficient the air conditioner. When buying a new room air conditioner, look for the ENERGY STAR label.

Sizing and Selecting a Room Air Conditioner

The required cooling capacity for a room air conditioner depends on the size of the room being cooled — room air conditioners generally have cooling capacities that range from 5,500 Btu per hour to 14,000 Btu per hour. A common rating term for air conditioning size is the “ton,” which is 12,000 Btu per hour.

Proper sizing is very important for efficient air conditioning. Buying a bigger room air conditioner won’t necessarily make you feel more comfortable during the hot summer months. In fact, a room air conditioner that’s too big for the area it is supposed to cool will perform less efficiently and less effectively than a smaller, properly sized unit. The reason: an oversized unit will cool the room(s) to the thermostat set-point before proper dehumidification occurs, making the area feel “clammy” and uncomfortable.” A small unit running for an extended period operates more efficiently and is more effective at dehumidifying than a large unit that cycles on and off too frequently.

Based on size alone, an air conditioner generally needs 20 Btu for each square foot of living space. Other important factors to consider when selecting an air conditioner are room height, local climate, shading, and window size.

Verify that your home’s electrical system can meet the unit’s power requirements. Room units operate on 115-volt or 230-volt circuits. The standard household receptacle is a connection for a 115-volt branch circuit. Large room units rated at 115 volts may require a dedicated circuit and room units rated at 230 volts may require a special circuit.

If you are mounting your air conditioner near the corner of a room, look for a unit that can direct its airflow in the desired direction for your room layout. If you need to mount the air conditioner at the narrow end of a long room, then look for a fan control known as “Power Thrust” or “Super Thrust” that sends the cooled air farther into the room.

Other features to look for include:

A filter that slides out easily for regular cleaning

Logically arranged controls

A digital readout for the thermostat setting

A built-in timer.

Installing and Operating Your Room Air Conditioner

A little planning before installing your air conditioner will save you energy and money. The unit should be level when installed, so that the inside drainage system and other mechanisms operate efficiently.

Don’t place lamps or televisions near your air-conditioner’s thermostat. The thermostat senses heat from these appliances, which can cause the air conditioner to run longer than necessary.

Set your air conditioner’s thermostat as high as is comfortably possible in the summer. The less difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be. Don’t set your thermostat at a colder setting than normal when you turn on your air conditioner; it will not cool your home any faster and could result in excessive cooling and unnecessary expense.

Set the fan speed on high, except on very humid days. When humidity is high, set the fan speed on low for more comfort. The low speed on humid days will cool your home more effectively and remove more moisture from the air because of slower air movement through the cooling equipment.

Consider using an interior fan in conjunction with your window air conditioner to spread the cooled air through your home without greatly increasing electricity use.

Remember that efficient operation of any air conditioning system relies on a properly insulated and air sealed home. For more information, see home energy audits and detecting air leaks.