Digital Camera Working Mechanism

WELCOME TO THE PRESENTATION
-BY MEHEDI HASAN
THEMAHADI@HOTMAIL.COM
5/23/2015 1

TOPIC ON PRESENTATTION –
HOW DIGITAL CAMERA WORKS
5/23/2015 2

In this presentation , we will discuss :
 What is – camera , digital camera
 History of – Old camera , Digital camera
 Types of digital camera
 Digital camera working mechanism
 Digital camera’s parts
 Digital camera’s features
 Future of digital camera
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Simply , Camera means capture image & store it for later use. Digital camera is a
revolution in a new digital age .All on a sudden ,Digital camera is not invented.
Before digital camera came , old camera is exist .so we look at first , World’s
first camera .
World's First camera
Which camera
took the picture
of the world’s
first camera?????
5/23/2015 4

Digital Camera -
A digital camera is a camera that capture images and turns them into digital
form.
Many digital cameras can also record moving videos with sound Some digital
cameras can crop pictures and perform other elementary image editing.
Example : -Kodak, Samsung , Lumix , Canon, Sony, Nikon, Olympus and
several other companies make digital cameras.
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Comparison between Digital camera & Human eye
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Digital camera history -
Steven Sasson as an engineer at Eastman Kodak invented and built the first electronic camera
using a charge-coupled device image sensor in 1975.
The 8 pound camera recorded 0.01 megapixel black and white photos to a cassette tape. The first
photograph took 23 seconds to create. To play back images, data was read from the tape and then
displayed on a television set .
5/23/2015 7

Ordinary Film Cameras History -
Film
box Negative
Previous on digital camera , film camera is used. Old film camera is useless without one vital piece of equipment is
called - a film. A film is a long spool of flexible plastic coated with special chemicals (based on compounds of silver)
that are sensitive to light. To stop light spoiling the film, it is wrapped up inside a tough, light-proof plastic cylinder
the thing put in the camera. To take a photograph with a film camera , have to press a button. This operates a
mechanism called the shutter, which makes a hole (the aperture) open briefly at the front of the camera, allowing light
to enter through the lens (a thick piece of glass or plastic mounted on the front). The light causes reactions to take
place in the chemicals on the film, thus storing the picture .When the film is full, it has to take it to a drugstore
(chemist's) to have it developed. The machine opens up the film container, pulls out the film, and dips it in various
other chemicals to make photos appear. This process turns the film into a series of "negative" pictures—ghostly
reverse versions of what you actually saw. In a negative, the black areas look light and vice-versa and all the colors
look weird too because the negative stores them as their opposites. Once the machine has made the negatives, it uses
them to make prints photos.5/23/2015 8

Types Of Digital Camera -
1. Compact digital camera
2.Bridge camera
3. Mirror less interchangeable-lens camera
4. Digital single-lens reflex (DSLR) camera
5.Digital Single Lens Translucent (DSLT) camera
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Image sensor -
An image sensor is a device that converts an optical image(Light) into an
electronic signal. On the surface of each of these fingernail-sized silicon chips is a
grid containing hundreds or thousands or millions of photosensitive diodes
called photosites, photo elements, or pixels.
Two major types of digital image sensor are :
1. CCD (Charge Coupled Device)
2. CMOS ( Complimentary Metal Oxide Semiconductor)
CCD and CMOS sensors perform similarly in absorbing photons, generating
electrons and storing them, but differ in how the charge is transferred and where it
is converted to a voltage. Both end up with a digital output.
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CCD vs. CMOS Sensors -
Once the light is converted into electrons, the differences between the two main sensor types.
The next step is to read the value (accumulated charge) of each cell in the image.
 CCD Sensor - The first digital cameras used CCD (Charged Coupling Devices) to turn
images from analog light signals into digital pixels. They're made through a special
manufacturing process that allows the conversion to take place in the chip without
distortion. This creates high quality sensors that produce excellent images. But, because
they require special manufacturing, they are more expensive than their newer CMOS
counter parts.
 CMOS Sensor - there are several transistors at each pixel that amplify and move the
charge using more traditional wires. The CMOS approach is more flexible because each
pixel can be read individually.
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Advantages of CCD Sensors -
1.Conversion takes place in the chip without distortion
2.CCDs have very high uniformity – Technique for HD
quality images (not videos)
3.More sensitive – Produce Better Images in Low Light
4.Produce cleaner and less grainy Images - low-noise images
5.CCD sensors is produced for longer period of time
Disadvantages of CCD Sensors -
1.CCD sensors Consume much more power
2.HD Video – Less pixel rates
3.CCDs are expensive as they require special manufacturing.
CCD Sensor
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Advantages Of CMOS Sensor -
1.CMOS consumes less power
2.CMOS sensors are cheaper
3.These Sensors produce better HD videos
4.CMOS cameras are used on Phones, Tablets
5.CMOS imager clearly has better performance
Disadvantages Of CMOS Sensor -
1.CMOS suffer more from structured noise.
2.CMOS sensors need more light for better image
5/23/2015 14

Capturing Color –
Unfortunately, each photosite is colorblind. In order to get a full color image, most sensors use
filtering(A filter is a transparent body that allows light of only certain color to pass through it) to
look at the light in its three primary colors. Once all three colors have been recorded, they can be
added together to create the full spectrum of colors to see on computer monitors and color
printers. There are several ways of recording the three colors in a digital camera such as,
 Beam Splitter
 Spinning Disk
 Interpolation
 Bayer Filter
 Demosaicing Algorithms
[We are only discuss - Bayer Filter]
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Capturing Color : Bayer Filter
The most common pattern of filters is the Bayer filter pattern. This pattern alternates a row of red and
green filters with a row of blue and green filters. The pixels are not evenly divided -- there are as many
green pixels as there are blue and red combined. This is because the human eye is not equally sensitive to
all three colors. It's necessary to include more information from the green pixels in order to create an
image that the eye will perceive as a "true color.“
The advantages of this method are that only one sensor is required, and all the color information (red ,
green and blue) is recorded at the same moment. That means the camera can be smaller, cheaper, and
useful in a wider variety of situations. In other words, it makes it possible to create an affordable handheld
digital camera. The raw output from a sensor with a Bayer filter is a mosaic of red, green and blue pixels of
different intensity.
The Bayer color filter
mosaic. Each two-by-two
sub mosaic contains 2
green, 1 blue and 1 red
filter, each covering one
pixel sensor.
5/23/2015 16

Color -
Colors in a photographic image are usually based on the three primary colors red, green, and
blue (RGB). This is called the additive color system because when the three colors are
combined or added in equal quantities, they form white. This RGB system is used whenever
light is projected to colors as it is on the display monitor (or in your eye).
Although the digital camera can record 12 bits or 4096 steps of brightness information,
almost all output devices can only display 8 bits or 256 steps per color channel. The original
12-bit (212 = 4096) input data must be converted to 8-bits (28 = 256) for output.
Each color's brightness can range from 0 to 255, for 256 .Zero indicates pure black, and 255
indicates pure white. 256 colors each of red, green and blue may not seem like a lot, but
actually it is a huge number because 256 x 256 x 256 = more then 16 million individual
colors. So , at last an image in the form of a binary file.
5/23/2015 17

Color , Computer & Number
Computers are very powerful at manipulating numbers, we can perform
different operations on these numbers quickly and easily. For instance,
contrast is defined as the difference in brightness between adjacent pixels.
For there to be contrast, there must be a difference to start with, so one pixel
will be lighter and one pixel will be darker. We can very easily increase the
contrast by simply adding a number to the brightness value of the lighter
pixel, and subtracting a number from the brightness value of the darker pixel.
Color in an image is represented by the brightness value of a pixel in each of
three color channels - red, green and blue - that constitute the color
information. We can just as easily change the color of a pixel, or group of
pixels, by just changing the numbers.
5/23/2015 18

Front of a digital camera parts Back sight of a digital camera parts
Parts of Digital Camera
5/23/2015 19

The main parts of a digital camera -
 Shutter button: Press this button all the way to take a picture.
 Control buttons: Adjust various camera settings.
 Shooting mode dial: Change among different scene modes, adjust exposure choices,
and so on.
 Microphone: Capture audio for movie clips and voice annotations, or even activate a
sound-triggered self-timer.
 Focus-assist light: Helps the camera focus in dim lighting conditions.
 Electronic flash: Provides addition light to your scene.
 Optical viewfinder: To frame and compose your picture.
 Zoom lens and control: Magnifies or reduces the size of the image.
5/23/2015 20

 Body: The body is the main portion of the camera, and bodies can be a number of different
shapes and sizes. DSLRs tend to be larger bodied and a bit heavier, while there are other
consumer cameras that are a conveniently smaller size and even able to fit into a pocket.
 Docking port: Can be used to transfer photos, recharge the batteries, make prints, or perform
other functions.
 Battery compartment: Contains the cells that power the camera.
 Power switch: Turn the camera on or off.
 Indicator LEDs: Show the camera’s status.
 LCD (liquid crystal display) panel: The camera’s display.
 Display control/Menu button: Controls the amount of information shown in the LCD and
menus.
 Picture review: Press this button to review the pictures you’ve already taken.
 Cursor pad: Navigate menu choices.
5/23/2015 21

 Wrist connector: The strap that keeps the camera securely tied to the wrist.
 Set/Execute button: Activate a feature or set a menu choice to the current
selection.
 Memory card slot: Accepts digital memory cards.
 USB port: Access for a USB cable.
 File-save LED: This light usually lights up to indicate that an image is being
saved to the memory card.
 Power Switch :This is the button or switch that turns the camera off, to save
battery life.
 Aperture: The aperture controls the amount of light admitted into the lens.
5/23/2015 22

Digital Camera’s Feature -
 Autofocus : Autofocus is extremely useful feature that allows to produce great images. Autofocus
simply means that the camera will identify the subject and make adjustments to get the best focus.
 Face Recognition: Face detection or face recognition has become one of the more popular digital
camera features in recent years. It allows the camera to identify faces in a shot and to automatically
adjust the focus, flash, and exposure to get the best shot of your subjects.
 Red Eye Correction or Red Eye Reduction : Red-eye is the result of the flash reflecting off of a
person, or pet’s eye. Avoid looking directly into the camera can help to eliminate this problem. However,
getting small children and pets to avert their eyes isn’t always possible.
Luckily many digital cameras now offer red eye reduction. This is an automatic feature that allows the
camera to make adjustments to prevent red eye effect.
5/23/2015 23

 Smile detection : Smile detection can help casual photographers be sure the human subjects they photograph are
captured while looking their best. The camera is able to detect when a smile occurs, take the picture at just the
right moment.
 Scene Modes : The shutter speed for a night shot may need to be slower than for a shot taken during the day time
in order to get enough light. scene modes allow us to make the necessary adjustments with the press of a single
button. Beach, snow, night, night portrait, portrait, landscape.
Burst mode :Gives users the ability to take several shots in rapid sequence without having to press the shutter
button each time or waiting for the camera to store each image. This mode is perfect when trying to take pictures of
movement. Burst mode is also called Continuous Shooting Mode.
Macro mode : This is useful when focusing on subjects up close. Using macro mode ,within a few inches and still
get a quality image.
Panoramic mode: Need to take wide angle shots. Open panoramic mode and move camera in the direction of the
image. It is almost like taking a video, but end up with a panoramic photo in the end.
5/23/2015 24

 Noise Reduction: Noise can come from the internal electronic components of the camera or high light
sensitivity among other things. Many image editing programs allow you to reduce this noise to improve
image quality.
 Anti-Shake: Even the steadiest of hands aren't completely still when pressing the shutter button. This
can produce blurring, streaks or soft focus when shooting in low light. Anti-shake (image stabilization)
helps neutralize jitters, producing sharper images. Many cameras allow you to turn off this feature.
 Pixels and Resolution: Digital images are composed of tiny units called pixels. More pixels mean
higher resolution. The larger the image, the more pixels are needed. Cameras that offer 12, 14, or more
megapixels .The amount of detail that the camera can capture is called the resolution, and it is
measured in pixels. The more pixels your camera has, the more detail it can capture.
256x256 - This is 65,000 total pixels. Poor camera.
640x480 – 307200 Pixel .Send photo via email or upload photo.
1216x912 - This is a "megapixel" image size 1,109,000 total pixels.
1600x1200 - With almost 2 million total pixels, this is “high resolution” .
2240x1680 - Found on 4 megapixel cameras ,with good quality for prints up to 16x20 inches.
4064x2704 - 11.1 megapixels takes pictures at this resolution. Can create 13.5x9 inch prints.5/23/2015 25

 Auto Exposure: Making sure that you capture the right amount of light is key to good
photography. Auto exposure makes decisions for you regarding relevant settings such as
shutter speed.
 Auto Correct: For even greater versatility, you can adjust a picture's exposure, color, and in
some cases, shadows.
 IS(Image stabilization) :The IS setting on a digital camera tells you how sensitive the
camera's sensor is to light. You can change the IS setting manually on most digital cameras.
Using a higher IS setting (like 400, 800 or 1600 for example) means it can be easier to take
good photos in dim conditions without flash. It can also mean action photos will have less
movement blur in them.
 white balance : All digital cameras have automatic white balance. This feature goes some way
to ensure your photos' colors are as accurate as possible.
 Zoom :Zoom is one of the digital camera features that even most ultra compact cameras offer.
Zoom allows the user to get a closer shot of subjects even when they can’t physically get
closer. Most Digital cameras have a digital zoom factor of 5X, and some of the more expensive
models have a digital zoom up to 12X / 13.1X/16X.5/23/2015 26

Interesting Features You May Or May Not Use -
Video: Most cameras offer some sort of low-resolution video capability that's appropriate for the Web.
Better cameras feature higher frame rates and full-frame size.
Time Lapse: Set up your camera on a tripod to take a series of pictures over a period of time.
Voice Recording: Use your camera to save conversations, memos about your pictures or to capture the
sound around you.
Text Tagging: You can add captions or keywords to your picture files to help identify and sort them.
Slide Show: Show compilations of your pictures, either on your camera's screen, on an attached TV or
computer, or, with some cameras, save the slideshow and share it.
Wireless Connectivity: If you want to send your photos to an e-mail address, website, or to a computer or
printer, this is the ticket.
5/23/2015 27

Future Digital Cameras
Some Feature of Future Digital Camera -
 Goodbye, Shutter Button: use a voice
command to tell the camera to record a photo
 Sense smell of photographs: Command the
camera to record the smell of the scene
 Redefining "Ultra Compact” : An ultra
compact camera generally is defined as a
camera that measures 1 inch or less in
thickness.
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Digital Camera Working Mechanism

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Digital Camera Working Mechanism

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