Lesson topic: “Digital information processing devices: digital video camera. Digital information processing devices digital devices

Digital devices

Analog Devices

Analog devices include functional electronic units designed to perform various operations and transformations on analog signals... Structurally, analog devices can be represented as:

1. Bipolar

It has 2 pairs of input terminals, to which the signal sources are connected, and the load is connected to the output terminals. It is a transmission link with control parameters.

Digital devices include functional units designed to perform operations on information objects in the form digital signals... Code words are used to represent digital signals. Features: the simplest alphabet is used for construction - two letters, denoted by the symbols 0 and 1. The code word is a number in 2 SS. The number of letters in the codeword is fixed.

A word contains n letters or digits. In digital devices, the objects of information are binary numbers, not functions of time.

Principles of functioning of digital devices:

1) A certain time is allotted to execute the command, for this a clock pulse generator is used, it formulates the control signal

2) After the start of the operation, all input code words are converted to the required output

3) Output codewords are sent to storage in the digital system memory or to external devices to perform actions

Ways to handle codewords:

To implement operations on code words, it is extremely important to have them in the form of electrical signals. A potential way of presenting has become widespread. Logic zero corresponds to low signal level (voltage), logical one - high. Operations on codewords can be performed in two ways: sequentially (bit by bit) and in parallel.

The simplest converters of information:

A computer consists of millions of elements: transistors, diodes, registers that make up integrated circuits. But the study of the work of a PC is facilitated by the regularity of its structure, which means: a computer consists of a large number of simple elements, there are several types in all. Elements form a small number of typical circuits.

According to the degree of complexity of the functions performed, they are distinguished:

1) Elements - the simplest part that performs operations on individual bits. Distinguish logically (and, or, not, and-not, or-not), memorizing (triggers different types) and auxiliary, serving to amplify and form signals.

2) Nodes - consist of elements and perform operations on words. Distinguish between combination and accumulative (sequential)

Combinational are built exclusively on logical elements;

Accumulators include logic gates and memory elements;

PC nodes include: registers, counters, adders, multiplexers, etc.

3) Devices - they consist of several nodes, perform one or a number of similar operations on machine words. Devices include ALU, memory device, control device, memory, input / output device.

Digital devices - concept and types. Classification and features of the category "Digital devices" 2017, 2018.

Processing device digital information and the "brain" of the entire publishing system is the computer, which is also a multilevel structure. It includes both processing elements (processor) and several types of information storage devices (random access memory, hDD, video memory), as well as a number of auxiliary elements (ports and other components)

Working with graphics, especially those intended for printing purposes, requires quite significant parameters of the computer used. Unfortunately (for the author only), the pace of technological progress in this area is unusually high, and the timing of writing, preparing, printing and distributing the book does not keep pace with them, so we will consider only the fundamental parameters that must be understood by every designer who sits down at a computer.

A personal computer is, first of all, system unit, which contains all the main components of the computer. The "brain" of a computer is microprocessor -the central device of the computer is an electronic circuit, several square centimeters in size, which ensures the execution of all application programs and control of all devices. The microprocessor is made in the form of an extra-large (not in size, but in quantity electronic components, the number of which reaches several million) of an integrated circuit located on a silicon wafer.

Microprocessors can differ in the following main parameters:

Type (model)means the generation of microprocessors, for example, there are processor series that are collectively called "286", "386", "486", "Pentium".

Clock frequency determines the number of elementary operations performed per second. It is measured in hertz (Hz). The clock speed is the main parameter for the performance of the processor. The higher the processor type, the higher the clock speed. One of the first models of personal computers had a processor with clock frequency 4.77 MHz, and the latest processors have crossed the 1 GHz barrier.

Bit depth defines the number of bits transmitted simultaneously (synchronously) over data buses. Computer performance is also directly related to bit depth. This parameter changes abruptly: 8 bits, then 16, 32 bits and finally 64-bit buses.

A computer as a whole is characterized by a number of other parameters that affect its performance.

Operational memory (or RAM - random access memory) defines the amount of memory that the processor "disposes" of. Random access memory is fast and volatile (information is completely lost when the power supply is cut off), in which the currently executable program and the data required for this are located. The higher this value, the more information can be simultaneously available for processing. Volume random access memory in a relatively short historical period, it increased from 640 Kbytes to tens of Mbytes in modern systems (and even in the most modest configurations). The performance (speed) of a computer directly depends on the amount of RAM.

Video memory -it is a separate RAM located on a dedicated video card. This memory contains data corresponding to the current screen image.

In a modern personal computer, the principle of open architecture is implemented, which allows you to practically freely change the composition of devices (modules). The main information highway connects a large number of peripherals... In this case, it is very important that some devices can be replaced by others. Even the microprocessor and memory chips are no exception.

Hardware connection of peripheral devices to the information highway is carried out through a special block, which is called controller (sometimes called an adapter). And software control of work external devices provided also special programs - drivers, which are usually integrated into the operating system.

Lesson topic: "Digital information processing devices: digital video camera"

The purpose of the lesson:

create conditions for the formation of students' ideas about the types and purpose of digital devices for information processing;

continue to develop skills in processing information using various devices;

continue to foster respect for computer technology, compliance with the rules of safe behavior in the office

DURING THE CLASSES:

1. Organizing time.

2. Review of the previous lesson:
1) what device did we talk about in the last lesson?

2) What are the main elements of the camera you can name?

3) What are the advantages of digital cameras?

4) Where are the images stored in the camera?

5) How is the transfer of images from the camera carried out?

3. Learning new material.

For today's lesson, you have prepared posts about digital camcorders - devices that greatly expand the capabilities of modern computers. We will conduct our acquaintance with this device according to the same plan as the acquaintance with a digital camera, i.e.

1 - the main elements of the video camera

2- advantages of digital video cameras

3– devices for recording information in a video camera

4 - transfer of information from the video camera to the computer

5– webcams

Let's give the floor to representatives of the groups.

(students make messages, if necessary, accompany the story with illustrations)

Material that can be offered to students is in Appendix 1.

4. Workshop on transferring video to a computer

Just like in the last lesson, you can shoot fragments of students' speeches, their activities in the lesson. In practice, show how to transfer a video (as a last resort from a camera). The form of work is individual.

5. Editing a video about the study of Digital Information Processing Devices

Working with video editorMoveMaker (frontal):

2. Upload video images - Record video - Import video.

3. Upload Photos - Record Videos - Import Images

4. Arrange video clips and photos on the storyboard panel (drag and drop)

5. Add transitions: Editing a movie - Viewing video transitions - Select a video transition - drag it to the storyboard panel in the area between frames.

6. Add effects: Editing a movie - Viewing effects - Select an effect - drag it to the storyboard panel directly onto the frame. To enhance the effect, it can be used several times.

7. Adding shooting galleries and captions: Editing a movie - Creating titles and captions - Selecting an effect for captions or captions - enter text, set formatting - click the "Finish" button.

8. Add music: Record video - import sound and music - drag and drop the fragment to the storyboard panel.

9. Saving the movie in formatWMV - Finish making the movie - Saving the movie to your computer - Confirm the save movie wizard's requests.

Give this algorithm to students as a memo. We do the work all together, the teacher shows everything the same on the screen.

6. Homework: In the next lesson, students will be doing a movie project. To do this, they will have to think over the subject of the project, what fragments and photographs they will use. In the lesson, they will have to shoot footage and edit a short film. (The topics are varied: My school, My class, Our computer science room, Our teachers, etc.) The work is supposed to be in groups of 2-3 people.

Appendix 1. Camcorders

Camcorders are primarily divided into digital and analog. Here I will not consider analog cameras (VHS, S-VHS, VHS-C, Video-8, Hi-8) for obvious reasons. They have a place in a thrift store, or on the top shelf in the closet (what if someday it will become a rarity), but the processing of analog video will definitely be considered, since, I think, everyone has a lot of cassettes. So, modern household video cameras differ in the type of video information carrier, in the method of recording (encoding) video information, in the size and number of matrices, and, of course, in optics.

1.1.1. By the type of storage medium, cameras are divided into:

HDV cameras: the newest and most likely future format. Frame size up to 1920 * 1080. Imagine, each frame is a 2 megapixel photo, and you will understand what the quality of the video is. Strictly speaking, HDV is a recording format, since there are HDD cameras that work in the HDV format. But I deliberately put this format in this row, since most of the existing HDV-cameras record on cassettes. If money is not a problem for you, these cameras are for you.

DV cameras: The main format for consumer digital video cameras. Frame size 720 * 576 (PAL) and 720 * 480 (NTSC). The recording quality largely depends on the optics and the quality (and quantity) of matrices. DV cameras are divided into DV (mini-DV) cameras and Digital -8 cameras. Which one to buy depends on you, on the one hand mini-DV cameras are more common, on the other hand, if you had a Video-8 camera before, it makes sense to pay attention to Digital-8 cameras, since these cameras record freely on any cassettes of 8 format (Video-8, Hi-8, Digital-8 (they can, of course, swear, they say, Video-8 is rather weak for me, but they write on them easily)), in addition, recording on cassettes of better quality (Hi -8, Digital -8), you will get a longer recording time than mini-DV.

DVD cameras. I am not a fan of this type of camera. Their recording quality is lower than that of DV-cameras, and even a disc with the best quality for them is enough for 20 minutes. But! If you are not pretentious about the quality (especially since the difference is not so noticeable on the screen of an ordinary TV) and you do not want to bother with making a movie, then encoding it into a DVD format, you can easily use a DVD camera. Moreover, you can quickly assemble a full-fledged DVD from the resulting files onto a 1.4 GB DVD (used in DVD cameras) using specialized programs (for example, CloneDVD and DVD -lab).

Flash cameras. Recording is performed on a flash card in MPEG 4 and MPEG 2 formats. The duration depends on the size of the card, the selected frame size and encoding quality. MPEG 2 is preferable because the quality is higher, but it takes up more space. But neither the one nor the other format, when processing video information by a camera for recording on a card, will not be able to provide a quality that is even slightly close to DV. Therefore, we can recommend such cameras for a gift to children or for filming in extreme conditions, since the indisputable advantage of these cameras is their compactness and the absence of mechanical parts (the exception is a zoom lens).

HDD cameras. The recording is made to the built-in hard drive. Recording can be done in all formats from HDV to MPEG 4 (depending on model). Perhaps, like flash cameras, this is the future of household camcorders, but unlike the latest HDD cameras, they can already provide excellent HDV quality, or up to 20 hours of good quality MPEG 2 recording on a 30 Gb disk. But let's look at this splendor on the other hand, recording 1 hour of DV format takes up 13-14 Gb on a hard disk, and after making some simple calculations, tell me that it is easier to rearrange a cassette or rewrite video to a computer after 2.3-3 hours of recording (to good quality you get used to it quickly).

1.1.2. Any digital video camera uses compression (compression) of digitized video, because at the moment there is simply no media capable of withstanding uncompressed video (one minute of uncompressed PAL 720 * 576 video without sound takes about 1.5 GB on the hard disk, simple calculations allow you to see that one an hour already needs 90 GB). And it is also necessary to process this huge amount of information, even a simple rewriting of 90 GB will take about five hours. Therefore, video camera manufacturers simply need to use compression of the digitized video. Modern video cameras use the following types compression: DV, MPEG 2, MPEG 4 (DivX, XviD).

DV is the main form of video compression in modern digital camcorders; it is used by HDV, miniDV, Digital 8 and some HDD cameras. The high quality of this type of compression, I think, will be leading among other formats for a long time.

MPEG 2 is the format used for dVD burner ... Although it has a slightly worse recording quality compared to DV, depending on the bitrate (roughly speaking, the number of bytes allocated per second of video) using given view compression, you can get a video of a fairly high quality (remember licensed DVDs).

MPEG 4 - to be honest, manufacturers of digital equipment (photo and video) have seriously tarnished their reputation this format... To "squeeze" everything possible out of this format, you must use enough powerful computer and spend a decent amount of time. Therefore, it turns out that the final video in MPEG 4 format on camcorders and cameras is of low resolution and low (to put it mildly) quality. What DivX or XviD is used is not so important, the difference (small), again, can be seen only when processing video on a computer.

1.1.3. An important, but rather basic, effect on the final result is provided by the quality of the matrix used to digitize the optical signal passing through the lens of the video camera. The bigger it is, the better. When choosing a video camera, do not be too lazy to look into the specification and see the number of effectively used pixels ("points" on the matrix). For example, the specification for the Sony XXXXXXX camcorder says that with a frame size of 720 * 576 (0.4 Megapixels), 2 Megapixels of the matrix are used for video. Naturally, this has a positive effect on the final result, since with any encoding (compression) the law is rigidly applied: the better the source material, the better the result, and the more light falls on the matrix, the less digital noise will be, the darker the time it will be possible to use a video camera, etc. All of the above in triple size refers to three-matrix cameras, among other things, the three-matrix system can significantly reduce color noise due to the fact that the separation of light into RGB color components (a prerequisite for obtaining a video signal) is not performed electronics, but an optical prism, then each matrix processes its own color.

Indirectly, the size and quality of the matrix can be judged by the built-in video camera digital camera, the more resolution it has, the better.

1.1.4. With video camera optics, everything is simple: the more, the better. The larger the lens diameter, the more light will enter the sensor. The greater the optical zoom of the lens ... However, it is worth dwelling on this in more detail. The first thing I want to say: NEVER look at the proud inscriptions on the side of the video camera (X120, X200, X400, etc.). You only need to look at the optical zoom of the lens (either on the camera (optical zoom) or on the lens itself). Of course, digital zoom can be used, but do not forget that digital zoom is a limitation of the number of effectively used pixels of the matrix (see figure). And just a 2x digital zoom (for example, with a 10x lens, this will be a 20x total magnification) will reduce the effectively used pixels on the matrix by 4 times!

Well, it would be nice to have an optical stabilizer, since cameras with a digital stabilizer do not use the entire matrix area.

Webcams

Webcams are inexpensive networked fixed devices that transmit information, usually video, over wireless or cross-connected Internet and Ithernet links. The main purpose of "room" webcams is to use them for video mail and teleconferencing. Such cameras are widely used in "baby-sitting" - they perfectly cope with the role of video nannies, transmitting the image of a child left to himself. "Street" anti-vandal webcams act as security video observers. The ability to capture images in camcorder or still camera mode is additional features webcams. Expect high quality from recorded videos or digital photo in this case not worth it. Because it makes no sense to equip webcams with high-quality optics and expensive electronics - transferring video data in real time requires incredibly high compression, which inevitably leads to a loss in image quality. Although it is fundamentally impossible to obtain a gorgeous picture using webcams, it is the quality of the resulting image that is the main characteristic that allows you to subjectively compare and choose cameras of this type. However, preference can also be influenced by an interesting design, software package and various options such as support for skins and additional communication interfaces... All webcams are equipped with a motion detector function and an audio input that allows you to transmit audio information, they are also often equipped with connectors for connecting various external sensors and devices such as lighting fixtures and alarms. World practice shows that the main manufacturers of webcams are becoming companies that manufacture computer peripherals (Genius, Logitech, SavitMicro) or network hardware (D-Link, SavitMicro), and not video or photographic equipment, which once again emphasizes the difference in the technologies used.

Video image compression formats

As an initial step in image processing, the MPEG 1 and MPEG 2 compression formats split the reference frames into several equal blocks, which are then subjected to a diskette cosine transform (DCT). Compared to MPEG 1, the MPEG 2 compression format provides better image resolution at a higher video bit rate through the use of new compression and de-redundancy algorithms and coding of the output data stream. Also, the MPEG 2 compression format allows you to select the compression level due to the quantization accuracy. For video with a resolution of 352x288 pixels, the MPEG 1 compression format provides a bit rate of 1.2 - 3 Mbps, and MPEG 2 - up to 4 Mbps.

Compared to MPEG 1, the MPEG 2 compression format has the following advantages:

Like JPEG2000, the MPEG 2 compression format offers scalability to various levels of image quality in a single video stream.

In MPEG 2 compression format, motion vector precision is increased to 1/2 pixel.

The user can select an arbitrary discrete cosine transform accuracy.

MPEG 2 compression format includes additional modes forecasting.

The MPEG 2 compression format used the now discontinued AXIS 250S video server from AXIS Communications, the 16-channel VR-716 video storage from JVC Professional, DVRs from FAST Video Security and many other video surveillance devices.

Compression format MPEG 4

MPEG4 uses a technology called fractal image compression. Fractal (contour-based) compression means extracting outlines and textures of objects from the image. The contours are represented in the form of the so-called. splines (polynomial functions) and are encoded by reference points. Textures can be represented as spatial frequency transform coefficients (for example, discrete cosine or wavelet transform).

The range of data rates supported by the MPEG 4 video image compression format is much wider than that of MPEG 1 and MPEG 2. Further developments are aimed at completely replacing the processing methods used by the MPEG 2 format. The MPEG 4 video image compression format supports a wide range of standards and baud rate values. MPEG 4 includes progressive and interlaced scanning techniques and supports arbitrary spatial resolutions and bit rates ranging from 5 kbps to 10 Mbps. MPEG 4 has an improved compression algorithm that improves quality and efficiency at all supported bit rates. Developed by JVC Professional - the VN-V25U webcam, part of the works line of network devices, uses the MPEG 4 compression format for processing video images.

Video formats

The video format defines the structure of a video file, how the file is stored on a storage medium (CD, DVD, hard disk or communication channel). Usually different formats have different file extensions (*. avi, *. mpg, * .mov, etc.)

MPG - A video file that contains video encoded with MPEG1 or MPEG2.

As you may have noticed, usually MPEG-4 movies have the AVI extension. The AVI (Audi o-Video Interleaved) format was developed by Microsoft for storing and playing video clips. It is a container that can contain anything from MPEG1 to MPEG4. It can contain 4 types of streams - Video, Audio, MIDI, Text. Moreover, there can be only one video stream, while there can be several audio streams. In particular, AVI can contain only one stream - either video or audio. The AVI format itself does not impose absolutely any restrictions on the type of codec used, neither for video nor for audio - they can be any. Thus, any video and audio codecs can be perfectly combined in AVI files.

RealVideo is a format created by RealNetworks. RealVideo is used for live TV broadcasting on the Internet. For example, CNN was one of the first to broadcast on the Internet. It has a small file size and the lowest quality, but you can watch the latest TV news release on the website of your chosen TV company without overloading your communication channel. Extensions RM, RA, RAM.

ASF - Streaming Format from Microsoft.

WMV - Video file recorded in windows format Media.

DAT - File copied from VCD (VideoCD) \\ SVCD disc. Contains MPEG1 \\ 2 video stream.

MOV - Apple Quicktime format.

Connecting to a PC or TV

The simplest connector - RCA AV-out - to put it simply "tulips" - is available in any camcorder, adapted for connection to any television equipment, and provides analog video transmission with the greatest loss in quality. The presence of such analog inputs in digital video cameras is much more valuable - this allows you to digitize your archives of analog recordings if you had a digital video camera before. In "digital" their storage period will be extended, and it will also be possible to edit them on a computer. Camcorders of the Hi8, Super VHS (-C), mini-DV (DV) and Digital8 formats are equipped with an S-video connector, which, unlike RCA, transmits color and luminance signals separately, which significantly reduces losses and significantly improves image quality. S-video input in digital models gives the same advantages to owners of Hi 8 or Super VHS archives. The built-in infrared LaserLink transmitter in Sony camcorders, using the IFT-R20 receiver, allows you to watch footage on your TV without connecting to it with wires. Just place the camcorder next to the TV at a distance of up to 3 m and turn on "PLAY". The more advanced Super LaserLink transmitter, which is equipped with all the latest models, works at a greater distance (up to 7 m). The presence of mounting connectors in the camcorder allows for line editing by synchronizing the camcorder with VCRs and an editing deck. In this case, on all devices connected to each other, the tape counter readings and all the main modes are controlled synchronously: playback, recording, stop, pause and rewind. In Panasonic camcorders, the Control-M connector is used for this purpose, in Sony camcorders - Control-L (LANC). Their specifications are incompatible, so we recommend that you check the conformity of the interface with the VCR and the video camera.

RS-232-C connector ("digital photo output")

Connector for connecting a video camera to the serial port of a computer for transferring still frames in digital form and controlling the video camera from a PC. In "sophisticated" models, instead of RS-232-C, an even faster "photo output" - USB interface is built in. All mini-DV and Digital8 camcorders are equipped with a DV output (i. LINK or IEEE 1394 or FireWire) providing fast transfer lossless digital audio / video signal. To do this, you need to have another device with support for DV-format - DV-VCR or computer with DV-card. Of course, camcorders that have, in addition to the output, also a DV input, are more valuable. Some firms produce the same model in two versions: the so-called. "European" (without entrances) and "Asian" (with entrances). This is due to the high customs duties in Europe on the import of digital video recorders, which can rightly be attributed to a video camera with a DV input. IEEE-1394, FireWire and i. LINK are three names for the same high-speed digital serial interface that transmits any kind of digital information. IEEE-1394 (IEEE - Institute of Electrical and Electronics Engineers) Designation of an interface standard developed by Apple Corporation (branded as FireWire). Designation adopted by the American Institute of Electrical and Electronic Engineers (IEEE). Most mini-DV and Digital8 camcorders are equipped with an IEEE-1394 interface that transfers digital video information directly to a computer. The hardware includes an inexpensive adapter and a four-wire or six-wire cable. Allows to transfer data at speeds up to 400 Mbps.

i. LINK

Digital input / output based on IEEE 1394 standard. Allows you to transfer footage to your computer. Camcorder models with i. Link increases flexibility through online editing, electronic storage and distribution of images.

Firewire

Registered trademark of Apple, an active company in the development of the standard. The name FireWire ("fire wire") belongs to Apple and can only be used to describe its products, and in relation to such devices on a PC it is customary to use the term IEEE-1394, that is, the name of the standard itself;

Memory card

On this card you can store in in electronic format photos, videos, music. With its help, you can transfer the image to your computer.

Memory Stick

Sony's proprietary Memory Stick is capable of storing images, speech, music, graphics, and text files simultaneously. Weighing only 4 grams and not exceeding a gum plate in size, the memory card is reliable, has protection against accidental erasure, 10-pin connection for greater reliability, data transfer rate - 20 MHz, write speed - 1.5 MB / s, read speed - 2.45 Mb / s Digital still image capacity on 4MB card (MSA-4A): in jPEG format 640x480 SuperFine mode - 20 frames, Fine - 40 frames, Standard - 60 frames; in JPEG 1152x864, SuperFine - 6 frames, Fine - 12 frames, Standard - 18 frames. MPEG Movies capacity on 4 MB card (MSA-4A): Presentation mode (320x2.6 x 15 seconds; Video Mail mode (160x1.6 x 60 seconds.

SD Memory Card

SD Card - A new standard postage stamp memory card that can store any kind of data, including a variety of photo, video and audio formats. Currently available SD cards are 64, 32, 16 and 8 MB. By the end of 2001, SD cards with a capacity of up to 256 MB will be on sale. One 64 Mb SD card contains about the same amount of music as one CD. Since the transfer rate to the SD card is 2 Mb / s, it will take only 30 seconds to rewrite from a CD. Since the SD Memory Card is a semiconductor storage medium, vibration has no effect on it, that is, there is no skipping in the sound, which occurs with rotating media such as CD or MD. Maximum audio recording time on SD card 64 Mb: 64 minutes of high quality (128 kbps), 86 minutes of standard (96 kbps) or 129 minutes in LP mode (64 kbps).