Mais uma mostrando o que sabe fazer na frente da Cam. Confira:

A la hora de desarrollar un videojuego, algún sistema de apoyo basado en realidad aumentada o recrear algún edificio histórico en 3D, se hace indispensable disponer de un modelo virtual del mismo. La tecnología ProFORMA, puesta a punto por la Universidad de Cambridge, utiliza algoritmos probabilísticos para obtener una replica digital tridimensional de un objeto de manera rápida y barata. Esto es posible gracias a que utiliza como dispositivo de captura una simple webcam. Los resultados, si bien no son comparables a los obtenidos por un sistema basado en láser, son asombrosos.   —–>>>    

Desde hace algún tiempo los expertos están trabajando en sistemas de adquisición de modelos tridimensionales en tiempo real. Lejos ha quedado la época en que para crear unafigura 3D había que pasarse unas cuantas horas ingresando coordenadas en un ordenador. Hoy día es posible trasladar un objeto real a un mundo virtual simplemente utilizando un -costoso- escáner láser que obtendrá por nosotros las coordenadas necesarias. Sin embargo, debido a su elevado precio, estos sistemas se encuentran absolutamente fuera del alcance del usuario ocasional. Los investigadores Qi Pan, Gerhard Reitmayr y Tom Drummond, de la Universidad de Cambridge, han puesto a punto la tecnologíaProFORMA, que permite obtener una réplica digital tridimensional de un objetoutilizando una simple webcam.

Por lo general, los sistemas de captura de objetos tridimensionales no funcionan en tiempo real. Si necesitas digitalizar el modelo de un edificio o de un coche para que forme parta de un entorno virtual, primero necesitas tomarte un tiempo para que el sistema de captura que hayas elegido realice su trabajo y envíe las coordenadas de cada uno de sus vértices al ordenador. Luego, con esa información y las texturas necesarias, el software podrá mostrar las vistas que necesites del objeto digitalizado.  ProFORMA es capaz de hacer esta tarea en un solo paso. A medida que el usuario va “mostrando” a la webcam diferentes caras del objeto bajo análisis, va obteniendo los puntos relevantes de su estructura. Al principio, cuando solo se han obtenido unos pocos “frames” de vídeo, no es capaz de generar un modelo aceptable. Pero luego de que el modelo ha girado unos cuantos grados, los algoritmos implementados por los muchachos de Cambridge comienzan a transformar la “nube” de puntos 3D en una serie de triángulos (“mesh”) que pueden ser “cubiertos” con las texturas apropiadas.

ProFORMA: replicas digitales tridimensionales de manera rápida y barata.

A partir de este punto, el modelo que va siendo creado en la memoria del ordenador ya puede ser mostrado en la pantalla. En el vídeo que han difundido, puede verse la velocidad con la que se alcanza este punto, y la habilidad que tiene el software para obtener puntos relevantes en tiempo real a partir de una simple cámara web. Es destacable la solidez que posee el software digitalización y seguimiento, algo que se pone en evidencia cuando el investigador desplaza el modelo real o lo sacude en el aire. Es muy posible que ProFORMA lleve la adquisición de datos 3D a los hogares. El costo del hardware es ridículo, y el software, basado en Linux, muy posiblemente sea liberado de forma gratuita. Pero, aunque no lo sea, una vez expuesta la idea seguramente aparecerá alguien capaz de escribir un software mejor partiendo de la base desarrollada por Qi Pan y sus colegas.

PinasCAM Mon Nov 23 18:00:39 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 18:00:39 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 18:00:39 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 18:00:39 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 17:15:28 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 17:15:28 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 17:15:28 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 17:00:19 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 16:45:19 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 16:15:24 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 16:15:24 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 16:00:23 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 15:45:19 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 15:30:19 CET 2009, originally uploaded by PinasCAM.

Previously I introduced this series on selecting a webcam by briefly discussing Image Resolution, Motion, Features, Service Providers, and external vs. internal models. This second and final installment, built on the list of topics introduced previously in Part I, discusses webcam mounting types, microphones, unique properties of the Mac, conference room options, and sources to purchase your webcam. At the bottom is a list of recommended webcams based on our experiences at Vonei, and an online source where you can purchase them.

A friend of mine pointed out that internal webcams on laptops are convenient, but are usually lower quality and can break more frequently. Closing the laptop screen repeatedly could eventually result in a small crack in the lens or a sensor misalignment due to the shock. My friend’s daughter got a Lenovo for college and the camera was broken in 2-3 months. She uses her laptop quite a bit and opens and closes it frequently. She reported there is now a big black line right in the middle of the picture, a symptom of a cracked lens Having an external webcam is a good safety net as well as a means of getting a higher quality image and motion.

Mounting Types. Webcams are usually optimized for desktop computers or laptop computers. What’s the difference? Desktop computers are likely to need a webcam that accommodates sitting on a flat surface. Clip-on webcams are not as ideal for flat surfaces. Desktop computer CPUs are often placed on the floor. To plug in your USB webcam to the CPU, and have the webcam sitting in a position showing your face requires a long USB cable. If you have a desktop look for these two features. A laptop requires the opposite characteristics. A clip-on webcam is ideal, and the smaller the better for carrying the device while traveling. A laptop is ideal for a short USB cable. After all, who would want several feet of USB cable coiled on their desk when they only need a couple of feet length between the USB port and the top of the laptop screen?

Webcams with microphones. Webcams come with or without a microphone. After the past couple of years in testing webcams I’ve come to the conclusion that it is best to use a computer headset with microphone, and not the microphone in the webcam. Computers are inherently not good speaker phones, and sound from the computer speakers could enter the webcam microphone causing an echo effect. A headset places the “speakers” on the ears, and the microphone right in front of the mouth. A headset provides the best audio experience, making the webcam microphone a non-required feature.

Mac webcams have unique characteristics. Macs are optimized for use with Apple’s services such as iChat. While they do a great job, it is inconvenient for video conferencing with people on PCs or Linux computers. The Macs will not release the webcam to other service applications unless you turn off webcam access to iChat, Photo Booth, and Skype. Also, Mac users need to select the USB webcam when they use their service. This is true even if the webcam is built-in. Why one has to select USB when the webcam is built-in is puzzling, but trust me, unless you do this the Mac webcam may not work on your video service.

Conference Rooms. Webcams are great when the users are sitting right in front of their computer. But what do you do in a large conference room with multiple people? A little known fact is that you can use a video camera, and some digital cameras, as a webcam. You will need a video capture cable to connect your computer to the video camera (source provided below). With a video camera you can mount in on a tripod on the conference room table and show everyone in the room. If the computer is plugged into a large screen monitor, or plugged into a projector and shown on the wall, everyone in the conference room can see the other parties. Plug in a USB speaker phone and you have a very low cost solution, avoiding a large investment in traditional video conferencing equipment.

Final thoughts before the recommendations. Lighting can play a major factor in the quality of the webcam image. Never sit with a window behind you, as the background light source will place your face in shadows. Having a desk lamp is very helpful in shining light on your face, improving both the image contrast and color. Another recommendation is to ensure that the webcam you purchase has been tested with the service provider you plan to use, and that the webcam works on your operating system. No one wants to purchase a webcam with good specifications and then find out it doesn’t work on Vista or has an interoperability issue.

Webcam recommendations and sources. After the past couple of years of experience with webcams I recommend the following units:

Brand Model Online Source Recent Price

Logitech QuickCam Pro 9000 www.newegg.com $75.99

Logitech QuickCam Communication MP www.newegg.com $44.99

Vonei V8019 www.videointerviewkits.com $19.99

WinBook WB-6185 www.microcenter.com $19.99

Video Capture Cable  www.videointerviewkits.com $39.99

I used to recommend the Microsoft LifeCam VX-3000 ($26.99 at newegg.com) until we had several users complain of interoperability with Flash video. I believe Microsoft placed a software patch on their website to fix this, so if you’re game for downloading software patches the Microsoft webcam may work well for you. TigerDirect.com is another online source for webcams. Check them out and compare pricing, but I generally find the other sites listed above will provide lower pricing. And, one of my biases will show here…friends don’t let friends buy webcams at WalMart. This is only my opinion, but if you are going to purchase at a retail outlet I’d stick with BestBuy or other electronics specialty stores.

I hope that this series of articles on picking a good business webcam has been helpful. I welcome your comments/suggestions/feedback with your own experiences. Whatever webcam you choose I hope you have a high quality experience!

Alan Fitzpatrick is the Co-founder of Vonei LLC which provides live video conferencing service across PCs, Macs, and Linux computers. VideoInterviewKits is an affiliate of Vonei LLC. Additional information about Vonei can be found on http://www.vonei.com.

PinasCAM Mon Nov 23 15:15:21 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 15:00:22 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 14:45:19 CET 2009, originally uploaded by PinasCAM.

Jag är hur trött som helst. Dessutom väntar 11 uppgifter på att bli gjorda de tre närmsta veckorna. Kul kul.
Idag ska jag beställa julklapp till Robin. Bäst att göra det nu innan pengarna hinner ta slut. Att jag vill köpa sneakers och nya kläder tar julen ingen hänsyn till. Men nog fan är det en bra julklapp killen ska få.
Själv har jag önskar jag mig bland annat denna jackan

Vi får väl se om någon rik, vänlig själ vill punga ut åttahundra kronor och ge mig den på julaftonsmorgonen…

PinasCAM Mon Nov 23 14:30:19 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 14:15:22 CET 2009, originally uploaded by PinasCAM.

PinasCAM Mon Nov 23 14:00:19 CET 2009, originally uploaded by PinasCAM.