OCR with Ubiquitous Webcam

Optical Character Recognition (OCR) technology has matured to include digital image processing and with the kind of processing power available in the average Personal computer, it should come as no surprise that in these days the accuracy of the OCR exceeds 99 %.

Typically most software commercial or free would require that you use a TWAIN compliant scanner to capture the image you want to use for converting to editable text. For best results this might be the only way as you need to present the best possible image for the OCR software to work upon. You will need to acquire black and white or grayscale image as color information would confound the OCR process.

In case your software has any issues working with your scanner, you can still save the scanned image in a TIFF (Tagged Image File Format) format and invoke the OCR software with this TIFF file. Most image editing tools will have no problem converting the images to this TIFF format.

When you are in the office, it would not be an issue to use the services of a desktop scanner to convert the magazine page or newspaper page to electronic format. Many a time you would see when you are traveling – a magazine article or a newspaper page which would be ideal to illustrate your stand. Only thing that would stop you is the lack of accessibility to a desktop scanner. You don’t have to wring your hand in despair anymore.

Your Laptop may already be equipped to take care of not only the means of capturing the newspaper/magazine page, but also the requisite software to convert the acquired image to editable text format. I wanted to do a bit of test in this line and this is what I found out.

I have a Laptop with barebones software installed and not too many techno wiz attachments. The notebook is equipped with a 1.3 mega pixel (extrapolated resolution) Web camera and MS Office installed amongst other things. A typical scenario.

I used the webcam to “capture” this image displayed here from an old magazine. You can see from the faded sepia toned color that the magazine must have been sitting at the shelf for ages. Again the choice of this torn page was deliberate to demonstrate that if we can get any decent result from such a faded magazine page, you should get far better results with a better recent subject.

Now you need an OCR software to complete the conversion process. You need to look no further than the standard MS office software suite for this.

Click on All Programs - > Microsoft Office - > Microsoft Office Tools - > Microsoft Document Imaging

You will have a “free” OCR software here and it will take the above image acquired from the Webcam. Just click on Page from the top menu and select the and you will get the following page:

Click on Tools - > Recognize Text using OCR and it will have converted the image into editable text ready to be ported to MS Word. Click again on Tools - > Send Text to Word and your MS Word will fire up with the converted text.

This is what mine did at the end of the exercise:

A T one tirn, p!opIe
did&t daw to svar
t3eMhe’r—go1d’ look. But
rw dlnw gold teamed
with pLItinuTn or white
ldz so in, and Ioks so
good, u wonder why it
took u so long. At InterCold. there i a .triking rngi. of unfussy, elcg.mt jcseItery — rings. earrin. chair . and pvidant in theit very f fordable Career Carals range. embellished with diamond and pearls. Prices begin at R 3.)OO. And for tho thinking of tying the knot, it you haven’t chcn our wedding nng yet, take a peek at the ‘Rings for E1rnitv’ range. You’ll go mad trying to make up your mind…

Not too good – You would say. But you had supplied a color image in the first place. With a bit of image manipulation and a grayscale image the eventual outcome is almost 85 % accurate. Not bad for a basic web cam based OCR.

Linux video camera Security II

A few months back we have dwelled on using a web camera to augment the security of our premises. We have talked about using the ubiquitous web camera to double up as a security camera. But there are several drawbacks in using a standard web camera for security applications:

It has a limited angle of vision – Originally a web camera is designed to have a 45 degree of view. It comes with a pre focused lens and the lens quality is not enough to provide adequate resolution for security purposes.

Even with a higher resolution web camera which provides 2 mega pixel resolution, the required resolution is still limited with the kind of illumination available at a typical office environment.

The illumination level required to provide sufficient detail for security is not enough with ordinary run-of-the-mill web cameras. So we will look at other options – Network Surveillance Cameras (network cameras and IP cameras) in this installment.

In this category we have a bewildering array of cameras available with many connectivity options – Wifi, built-in Network card with/without Image compression software to obviate the need for one at your server end. Many come equipped with optical zoom and Pan/Tilt head assembly. The camera can be controlled through a control panel in the built-in server.

As these cameras are designed for security applications, they have low light sensitivity – often as low as 0.05 lux and coupled with optical zoom in the range of 10 X – you have a decent security camera that can “identify” the license plate number of a visitor’s car in the driveway.

One thing we have noticed in our camera is that the camera lens soon picks up enough dust (possibly owing to the power supply providing a positive electro static charge) which results in a grainy image. So for best results, keep your camera lens/assemblies scrupulously clean.

We also provided a bank of Infra Red LEDs to provide additional illumination wherever required (indoors). Needless to say, almost all cameras we tested contained enough sensitivity in the infra red region. In case you have a doubt, use any infra-red remote control to shine at the camera. You should see a line of white light being emitted from the remote control.

Some web cameras deliberately use an infra-red filter between the pickup device and the lens.

But as we have decided to use specifically crafted Surveillance Cameras, this would not be an issue.

As this is a Hands-on approach to the installation and maintenance of Network Surveillance Cameras, we will start with the selection of cameras first. For outdoor surveillance it would be prudent to go in for a robust enclosure to house the camera and in these days, there are quite a number of manufacturers who build specially designed metal enclosures with industry grade mounting brackets.

Compared with a traditional type CCTV camera installation, Network type camera installation offers several advantages:

1 Cost – Compared with low loss video type coaxial cables, Data networking cables are cheaper.

2. CCTV cameras which provide CVBS (Composite Video with Blanking Signal) output need to have a short run to the distribution amplifier or monitor to avoid high frequency signal loss. All analog systems suffer from this cable distance issues Network cameras use a data encoding system to send binary data across a shared network.

3. Advanced Functionality is easy to implement using software in the case of Network cameras while you need expensive dedicated hardware for the traditional CCTV network.

4. Easy scalability – you can add as many cameras as you require – limited only by the software. You can add individual units as you go.

5. Remote Monitoring and ease of storage: With dropping prices of hard disks and vast quantities of storage space available, you can save to disk all of the outputs from the cameras for later analysis. With suitable authentication, you can monitor your office half way across the globe through internet.

Part I

Our commercial video surveillance system had a problem last week. The mains supply unit that feeds the camera, which in turn uses a CCD (Charge Coupled Device) and transmits to the receiver through microwave (2.4 GHz) had failed. To add to our woes, the multiple camera switcher unit had failed as well – possibly owing to a disastrous power supply fault.

It would take some time to sort out this issue and procure replacement units to handle the security of the premises. Someone suggested that we explore using the ubiquitous webcams lying around in our office, coupled with some open source (or commercial) software to handle the perimeter security.

A quick search in the Google for the term – “linux video camera security” returned some 9 million pages. Zoneminder appeared to suit our requirement though our needs were more modest. The site mentions that it is a complete “ all in one Linux GPL’d security camera solution” .

Basically what we needed was as enumerated below:

1. Option of using inexpensive USB webcams
2. Option of using a Multi camera setup
3. Software driven Motion detection
4. Video streaming through the Net
5. Option of storing the images generated in the high capacity Network File Server

Browsing through the supplied manual (readme.pdf) showed that Zoneminder would more than suit our requirements.

There are many ways you can download and install the software package.

You can download and compile the source code or download your distro specific RPM to install. You will find that most of the code is written in Perl, which makes managing/ fault finding that much easy for people conversant with Perl.

You will need amongst other things – an Apache server with PHP and Mysql installation. There are other essentials too - libjpeg.a , libpcre.a , ffmpeg or the Berkeley MPEG encoder – if you plan to generate MPEG video. Fortunately if you are with any modern distros, you can use any of their built-in updating to obtain the required libraries.

We will explore how we built from the ground up a very versatile video camera security system with little more than a Linux box and a few readily available Webcams in our subsequent parts.

We join the Earth day celebration in a small way - by our efforts to disseminate information about practical conservation and tips on Energy saving. Global warming has become a mantra in the media now. Steps to reduce the production of CO2 (carbon dioxide) that contributes to the global warming by the Green House effect can be attempted by anyone who has an interest in preserving Mother Nature.

We provide below some tips and guidance on Energy Conservation:

1. Air conditioning and Heating: Different people require different temperature settings for comfort. We feel comfortable when our bodies lose heat at the same rate as we produce it. Heat production varies with physical activity and our metabolic rates. At the same time, heat loss or heat gain depends on surface temperatures in the room, air movement and air temperature. What all this means is that your comfort factor depends on a lot of factors - one of which is the temperature. Start by setting your thermostat a couple of degrees low.

Energy Efficiency Rating: The energy efficiency rating (EER) of an air conditioner is its BTU rating over its wattage. For example, if a 10,000-BTU air conditioner consumes 1,200 watts, its EER is 8.3 (10,000 BTU/1,200 watts). Aim for a higher EER. Turn off the unit when no one is present. If you have a Voltage regulator for pre-conditioning the supply, turn that off as well.

Better Thermal Insulation: A false ceiling with better heat insulation efficiency can reduce as much as 20 % power bills. An energy-efficient house has a much higher insulation value. It has the ability to resist heat transfer and fasten the heat loss. Materials that weigh a lot store more heat and have high thermal mass. Use of such materials can reduce heating and cooling energy requirements by nearly 25% as compared with mere brick veneer houses.

Power Factor Correction: All electric motors consume reactive power from the supply. Power factor correction capacitors correct the anomaly in the power supply. Discuss with your electric contractor the size of the power factor correction capacitor and its installation. It could save about 10 % from your utility bills.

2. Replace all incandescent bulbs with CFL (compact Florescent Lamps). CFLs are very energy efficient. A 15 W CFL will provide the same amount of illumination as a 60 W normal bulb. But they can’t be dimmed using conventional dimmers. Clean all lamps and lamp shades periodically. A clean lamp and a clean lamp shade enhances light transmission.

3. Inflate your automobiles tires to the manufacturer recommended pressures. Inadequate pressure in your tires can increase rolling resistance by as much as 20 %. Combine trips and chores so that you save on precious fuel. Remove top carriers when not required. They increase wind resistance. Drive at a sedate speed to improve your mileage.

4. Turn off your computers and monitors when not in use unless you are running a data center. A typical Switch Mode Power Supply (SMPS) of a desk top computer consumes about 400 W of energy most of the time. Use a TFT LCD monitor if you are using the conventional CRT (Cathode Ray Tube) monitor. A typical 17 inch CRT monitor consumes about 120 W while the same sized LCD monitor takes in about one fourth of the energy. The heat produced by the CRT also heats up the neighborhood adding to the cooling cost.

5. Invest in automation. A PIR (Passive Infra Red) movement sensor based outdoor lighting can help save considerable energy. You can use them in aisles and elsewhere where manual switching on and off of lights is inconvenient. You will find more tips in energy saving in our article.

Spread the word around.

We have covered the basic but most essential tools earlier. The list is not exhaustive and a whole lot depends on the type of job you plan to undertake. For most household repairs and the odd job in your car, you can make do with the tools we list here.

Utility Knives: Utility Knife comes in many shapes. Most use replaceable blades. When the tip of the blade loses its sharp edge, break it off with a pliers, observing standard precaution – Keep the knife away from the body and your face. The broken metal can fly off …

Electric Drill : Electric mains operated drills have more torque than their cordless cousins of similar sizes. But cordless drills are versatile and can be used anywhere without tethering to a mains outlet. Drills have amazing varieties of attachments – from buffing to sharpening your knives – you can use your ubiquitous drill.

Keep the batteries always charged when not in use to conserve the battery life. Most cordless drills are powered by Nickel cadmium batteries, which tend to lose their capacity when made to sit under discharged conditions.

Tapes: Keep a stock of electric insulation tape, duct tapes and measuring tapes handy in your tool kit. Remember to encase any temporary electrical connection joints in insulation tape. It is never pleasant to receive electric shocks …

Multimeter: This comes in handy to test for many electrical / electronic works – from testing continuity in circuits to measuring the current or measuring the voltage at the outlet. Again these meters come in many sizes with varying capabilities. A simple digital multimeter (DMM) capable of measuring upto 20 Amp AC/DC current will be adequate for most purposes. They can measure with adequate precision volts up to 900 or higher. They can beep or buzz when the prods are shorted or when there is continuity up to a few Ohms.

There was a time people used analogue meter movements in the Volt Ohm Meter (VOM). These meters use D’Arsonval Meter Movements, which are very sensitive and need careful handling as they use jeweled bearings. And they cost a packet of money. With the advent of digital revolution, digital meters have become insanely cheap to own.

Ensure that you have set the meter to the right function before connecting the prod. When you select the function to read the current and apply the prods directly across the mains supply – you are causing a direct short in the mains supply !

Currents are always measured in series with the equipment and the supply. Voltages are measured across the source. Switch off the mains when you test for continuity.

Find a good toolbox to store your collection of tools. Smear thin grease on the movable joints of tools. But the handle sections must never be greasy or be smeared with oil.

In this part we consider more tools which will be useful for any general purpose job around the house or in your garage. But primarily we will devote more attention on some of the basic precautions needed to work with or handle electrical circuits.

1. Spanners or Wrenches– They come in all sizes and shapes. The most versatile and the most abused spanner is the Adjustable Wrench. As we have said many times, always exercise caution in using them. Apply force only in the direction of the fixed jaw and not in the direction of the movable jaw. A movable joint takes a lot of punishment and eventually the grip loosens. If the nut or bolt slips, you run the risk of injury as well. Alternatively, any undue force applied can wreck the bolt or its head. Another type to work with pipes and pipe fittings comes with serrated jaws is called as Pipe wrench. Look for prime quality drop forged wrenches for long life – both for self and for the tools.

Fixed Wrenches are available in many forms too – Open ended, combination or socket types ( box spanners). Ideally box spanners enable the application of maximum force with minimum damage. Buy a set of spanners - with various sizes.

2 . Line Tester – A small screwdriver which has a built in neon bulb that lights up when the tip comes in contact with a live wire. You must touch the back end of the tester while testing for live wire. That provides the return path to the neon bulb’s electric circuit. This tester is the basic tool to identify the live wire when you are working with mains supply.

Working with mains electricity:

When working with mains supply it is essential to be highly cautious. A normal household supply in the US is 110 Volts while in Europe it is 220 Volts. The higher the voltage the higher is the possibility of passing higher currents. “It is the mills that kills and volts that jolts” goes an old saying about electricity. The mills here represent the milli amperes. Ampere is the unit of current. As low as 8 milliampere can result in fatality when it passes through our body.

In a dry environment, most individuals exhibit skin resistance of around 100 K Ohms. Ohms is the unit of resistance. However, when the skin is in contact with moisture or liquid, the resistance drops to less than a few K Ohms, which will allow dangerous currents to pass through bodies. This is one of the main reasons why restrooms and bathrooms are veritable death traps when you come in contact with the mains supply.

Always turn off the power supply before you undertake any repair. When you are rigging up power to outside the house, use a suitably rated 1:1 isolation transformer for better safety. Normally a household mains supply is configured with a live (Red wire) and a neutral (black wire) between which there exists a 110 Volts potential difference. The neutral connection is referenced to the ground and hence anyone touching a live wire standing on the ground poses the fatal return path to the mains supply. Adding an isolation transformer makes the electrical supply floating without any reference to the ground. Next time when you rig up the outdoor Christmas lightings, add an adequately rated isolation transformer.

Most households these days invest in residual current circuit breaker or residual current device or Ground fault Circuit Interrupter or Earth leakage circuit breaker – which all refer to the device which trips the power supply when there is a residual leakage current from a faulty appliance. These devices trip the power supply within a few milliseconds. Still it is prudent not to depend on them always when you draw power to exposed regions outside the house.

Disclaimer: This series of articles contains general information on home maintenance of household machinery. This is not an exhaustive list of service procedures. A lay user can only attend to general maintenance with limited skills and tools. All electrical and electronic machines operate at lethal voltages and can CAUSE serious damage or even electrocution or shock hazard to self and home. It is positively dangerous to even attempt to repair any electrical machine without the required skills or knowledge. Always refer servicing to qualified technicians or the dealer. For detailed troubleshooting, refer to owner’s manual and service manual if available. The information contained herein is only for general reference and does not carry any warranty implied or otherwise. You use the information provided here at your own risk.

We have covered hundreds of articles on Home Improvement and home appliance care in our women portal – Targetwoman. It dawned on us last week – when our front office lock jammed and held us captive inside for a few hours until an enterprising colleague decided to take matters into her hand and released the lock by unscrewing the lock’s outer bezel … that women can be very handy too as much as their male counterparts – only if they had the right knowledge and tools.

With that enlightenment, a consensus was arrived to the immediate effect that some kind of detailed information and steps to become a “handywoman” must be included in our repertoire.

Our Admin who has over 10 years of experience as an electronics bench service engineer in his earlier avatar was roped in to write about this series on – Handywoman.

We will cover some easy hands-on projects in this section as well to illustrate that anyone can attempt and complete successfully easy household tasks and home maintenance with the right information and right tools. It is not rocket science and all you need is a bit of patience to learn a few basic skills.

With that as the prelude to this section, we start with the basic hand tools.

Tools last a lifetime if you buy the right quality tools. Generally speaking hand tools are made of forged steel and should last for generations. Do not buy cheap quality tools. They can cause potential injury and invariably useless. Buy only the best quality tools and working with them can be a pleasure. And most importantly use a tool for what it was intended. Never try to substitute a tool for another most appropriate tool.

Any toolkit worthy of its name should at least include all of the following:

1. Screw Drivers - A set of straight bladed - slotted (old fashioned but still in use ) and cross slotted (Philips and Pozidriv). The most versatile for home use is the screw driver set with detachable head and various bits. Still you may need a long bladed straight blade screwdriver to reach inside some cabinets. Screw drivers come in all sizes – from small miniature jewel- makers screw driver set to standard sizes. Use the right size bit for the size of the head of the screw. A wrong bit can chip away the head and you will be stuck with it.

If the screw refuses to budge, leave a drop of penetrating oil to slacken it.

Some battery operated (electric) screwdriver sets are available which makes life easy when you need to fix many screws in a short time. For occasional use, you will be better off with a manual set of screwdrivers. Battery operated power tools, as we will see later in this series, pose some limitations. You need to keep the batteries in a charged state at all times. Nickel cadmium batteries or the heavier lead-acid storage batteries do not take kindly to long periods of discharged conditions.

2. Pliers – Cutting pliers or combination pliers and a long nosed pliers. Get the pliers with thick plastic wrapped handles for working on electric circuits. Comes easy on your hands too.

3. Hammer – A claw hammer is preferable over a ball-peen hammer. The latter which has a hemispherical head is more useful for tapping punches and rivets. A claw hammer comes in handy to pull nails. Check your hammers before you use them as any loose head or damaged handle can result in catastrophic injury to anyone nearby. Wear thick padded gloves and safety goggles when you use a heavy hammer to avoid injury.

We will add more tools to our kit as we go along ….