Color Space

COLOR SPACE

Di dalam penyimpanan digital video, terdapat dua konsep dasar dimana kita melakukan penyimpanan digital video. Yaitu RGB dan YUV.  Masing – masing tipe memiliki sebuah variasi atau dua variasi yang dapat menentukan tingkat akurasi  mereka. Untuk tipe RGB, terdapat tipe RGB16, RGB24, RGB32, dan untuk tipe YUV terdapat YUV2, YUV12, I420, dan lain-lain.

RGB menyimpan video lebih intuitif. RGB menyimpan setiap nilai warna  ke dalam 3 level warna, Red, Green, dan Blue ke dalam setiap basis pixel. Tipe RGB yang paling umum di gunakan saat ini adalah RGB 24 yang bernilai 8 bits pada setiap level warna (sehingga memiliki range 0-255 yang merupakan hasil dari 2⁸ = 256) dimana warna putih bernilai 255,255,255 dan hitam bernilai 0,0,0.

RGB menggunakan prinsip bahwa ketiga komponen warna dapat digabungkan untuk menghasilkan bermacam – macam warna. Sedangkan YUV  menyimpan warna berdasarkan prinsip kerja otak manusia di dalam menangkap warna.Hal terpenting di dalam prinsip kerja otak manusia adalah brightness (tingkat kecerahan) alias Luma

Luma dengan mudah dapat di tentukan dari RGB channels berdasar nilai rata- rata dari color values dan menambahkan nilai tertentu pada beberapa Warna untuk menemukan nilai Luma nya. Para ilmuwan telah menemukan tingak besaran nilai yang sesuai dengan persepsi otak manusia. Dimana warna hijau memiliki kontribusi terbesar, merah ½ warna hijau, biru ¹/₃ warna merah. Hal ini menunjukkan cara kerja otak dan hal ini merupakan pedoman bagi pengembangan sistem YUV.

Luma merupakan permodelan yang sederhana dimana Nol bernilai hitam dan Nilai Tinggi bernilai putih. Di dalam permodelan warna, hal ini bukanlah hal yang sederhana. Hal ini dikenal dengan istilah U dan V (atau Cb dan Cr). Keduanya memiliki nilai positif dan negatif yang bersesuaian dengan warna yang ditangkap oleh otak kita.

            Ketika Cr bernilai positif, berarti object tersebut berwarna Merah. Apabila Cr bernilai negatif, maka objeknya berwarna Hijau. Otak kita memahami kedua warna tersebut secara berlawanan.

            Apabila Cb bernilai positif, maka objek berwarna biru. Dan jika Cb bernilai negatif, maka objek akan berwarna Kuning. Dan kedua warna ini juga dipahami secara terbalik oleh otak kita.

            Ada beberapa faktor yang alasan mengapa penyimpanan video lebih baik menggunakan format YUV. Antara lain :

1.      Aspek Historis.

Ketika TV berwarna mulai berkembang, TV berwarna dituntut untuk dapat mendukung keduanya (TV warna dan TV hitam putih). Channel TV hitam-putih akan menjadi luminance,  manakala terdapat dua channel warna di tambahkan di atas permukaannya. TV hitam-putih akan mengabaikan kedua channel tambahan tersebut dimana TV itu hanya memahami bahwa Chroma bernilai Nol  di dalam sinyal Hitam-Putih.

2.      Channel warna yang dihasilkan dapat terhubung secara teratur

Ketika sebuah bayangan bergerak, hanya sebuah channel warna yang berubah. Hal ini sangat membantu di dalam kompresi video, karena sebuah informasi yang sama tidak akan diproses ulang untuk channel yangberbeda.

3.      Channel yang di dapatkan adalah channel yang dibutuhkan.

Ketika sebuah video ditampilkan, maka tidak semua channel warna ditampilkan secara keseluruhan dan bersamaan.

   

Pengumuman Prak. PTI B1

Assalamuallaikum Wr. Wb.

Kepada semua praktikan PTI B1, asistensi terakhir hari Senin (8 Oktober 2012).
Perhatian, untuk hari Sabtu & Minggu (6 & 7 Oktober 2012) kegiatan asistensi tidak dapat dilaksanakan. Jadi, tentukan waktu anda. Jazakallah.

Wassalamualaikum Wr. Wb

Comparison Information System Model

Many people or associations struggle with their management information system and database maintenance. The primary problem is decide the model of information system they’ll apply. There’re some model for information system that commonly used. Every model has some advantages and disadvantages.

Centralized Information System

·         Advantages

            This model has several benefits for database processing and maintenance. There are :

1.      Data Integrity

The greatest benefits of centralizing an associations data management is data integrity. One of the cardinal rules of database design is that no redundancy is allowed. It’s mean, that no piece of single data that should ever process repeatedly. When an assn Operating multiple database for the same group (example : a membership database with a separate meeting registration database), it’s definitely breaking the rule. A centralized database means that each member has one primary record, with primary contact information.

2.      Valuable broad marketing info/history

When we apply a centralized database, it’s easier to develop , maintain , and check all activity in our database system. With multiple database, records need to be matched, de-duping need to be occur, and the opportunity for duplicate records must be increased.

3.      Reduce the training process (cost saving)

Centralized system is different with multiple system. All processes (membership, meetings, products, etc) are in the same database. So, the users need only learn one database system. And it’s make the user easier to handle the system management.

4.      Support

In centralized system, support is focused on a single system. But, in the multiple database, even if “they” are built on the same platform, “they” need a separate support.

·         Disadvantages

There are several less point of centralized system.

1.      Centralized system entail a high cost disadvantage

The information system professional who install and operate such system are also expensive. The bureaucracy and inflexibilyty of system can increase the cost.  One central system carrying out all the requested task, it cause the system going to be much slower than a decentrlized system where each system unit has its own autonomous system for local tasks.

2.      High risk fails

In the centralized system independent processing is not allowed. All task is handle by one CPU in centralized processes. If the CPU fails, the entire system is inoperable.

Decentralized Information System

·         Advantages

1.      Decentralized system gives autonomy

Decentralized system gives autonomy over the resources without any major considerations.

2.      Flexibility

3.      Reliability

On decentralized system, reliability is the greatest advantage because multiple computer system are involved. If one computer system fails, the system or at least part of it will still be able to operate.

·         Disadvantages

In this case, decentralized system also has several less point.

1.      Decentralized systems lack a centralized control.

It can be very disadvantageous as conflicting ideas arise and clashes in policy lead to delay and inefficiency. In the other side, the one vendor may not support all many different components of the overall systems.

Client Sever Information System

·         Advantages

1.      Dependency on the System

Client-to-Server network operating systems depend on the operating system to function. When the server get down or malfunction, the system is getting inoperable. . Peer-to-peer systems have the advantage of an existing operating system for each computer linked into the network to depend on so each computer can function easily as a separate unit. For information storage, all data save in the client server and manage in the centralized system.

2.      Versatility

New technology is easily integrated into client-to-server network connections as the operating system is controlled centrally. Of course when this new technology is integrated into the system, a given staff must then be trained to use the new technology which can be time consuming and have a few pitfalls as workers integrate the new system into existing protocols. Peer-to-peer systems depend largely on existing software platforms installed on computers linked to the network and while systems for the entire network cannot be changed, each user is able to customize a work station to optimize personal efficiency.

·         Disadvantages

1.      Expensive Cost

Client to Server System is equal with an expensive cost.

2.      Congestion Network System

To many request from client to server can rise congestion. The overload of request can brakeing-down the server.

3.      It’s not Robust

Client-Server model is not robust. Because, when the server fais, all syatem is going to be down.

4.      Great resource requirement

We need Professional IT to maintain the servers an all of technical problem..

Source :
* http://www.ianswer4u.com/2011/05/client-server-network-advantages-and.html#axzz27tIDa1oO
* Centralized versus Decentralized Information Systems in Organizations , Melissa Beck , LI805XR Spring 2010 , Emporia State University
* http://www.effectivedatabase.com/why-should-you-have-a-centralized-system