Digital cameras capture images using electronic sensors like CCDs and CMOS, converting light into digital data. They offer various features compared to traditional cameras, including multiple storage options and higher image resolutions. Different types of digital cameras include compact cameras, mirrorless interchangeable-lens cameras, and others, which process and compress images for efficient storage and transmission.

1. DIGITAL CAMERA
ESD GROUP 3

2. WHAT IS DIGITAL CAMERA?
• A Digicam is a camera that takes videos or still
photos by recording images on an electronic
image sensor.
• Many digital cameras are incorporated into
many devices ranging from PDA’s and mobile
phones.
• They share an optical system using lens with
variable diaphragm to focus light on image
pickup device.

3. • light reflected from an object enters the
camera and passes through convex lens that
captures the image.
• Early cameras used the PC serial port. USB is
now most widely method though some has
fire-wire port.
• The other cameras used wireless
communication such as Bluetooth 802.11.
• Pressing the button of camera opens the
shutter so the light from the object travels to
the back of the camera instead.

4. • For most a conversion to digital is required to
give enough space for electronics and allow a
LCD to preview the image and replacing it with
built digital unit.

5. HOW DIGITAL CAMERA WORKS?
• It converts analog information (represented by
fluctuated wave) into digital
information(represented by ones and zeros or
bits)
• Once a picture is taken image pic must be
converted into a form that computer can
recognize (bits and bytes)
• A digicam has different lenses that helps to
focus the light to create image of the scene

6. • Digicams uses CCDs (charged coupled devices)
or CMOS.
• CCD sensors create high quality low noise
images but CMOS sensors are more
susceptible to noise.
• Lets have a look what is the real difference

7. SIMPLE DIGITAL CAMERA
• Captures images
• Stores images in digital format
– No film
– Multiple images stored in camera
• Number depends on amount of memory and bits used per image
• Downloads images to PC
• Only recently possible
– Systems-on-a-chip
• Multiple processors and memories on one IC
– High-capacity flash memory
• Very simple description used for example
– Many more features with real digital camera
• Variable size images, image deletion, digital stretching, zooming in and out, etc.
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8. TYPES OF DIGITAL CAMERA
• Compact digital cameras
• Mirror less interchangeable-lens camera
• Line-scan camera systems
• Bridge cameras

10. HOW DO DIGITAL CAMERAS
CAPTURE COLOR?
• To get full color of an image, most sensors use
filtering to look at the light in its three primary
colors
• All three colors get recorded and combined to
create the full spectrum
• Beam splitter – directs light to different
sensors and each sensor only responds to one
of the primary colors

11. EXPOSURE AND FOCUS
• Digital camera has to control the amount
of light that reaches the sensor.
• The two components it uses to do this, the
aperture and shutter speed, and are also
present on conventional cameras.

12. • Aperture: The size of the opening in the
camera. The aperture is automatic in most
digital cameras, but some allow manual
adjustment to give professionals and
hobbyists more control over the final
image.
• Shutter speed: The amount of time that
light can pass through the aperture. Unlike
film, the light sensor in a digital camera
can be reset electronically, so digital
cameras have a digital shutter rather
than a mechanical shutter

13. STORAGE
• Many camera phones and most separate
digital cameras use memory cards having flash
memory to store image data.
• The majority of cards for separate cameras are
SD format; many are CompactFlash and the
other formats are rare.
• Digital cameras have computers inside, hence
have internal memory.

14. • A few cameras use some other form of
removable storage such as Microdrive's (very
small hard disk drives), CD single (185 MB),
and 3.5" floppy disks. Other unusual formats
include:
• Onboard flash memory — Cheap cameras and
cameras secondary to the device's main use
(such as a camera phone)
• PC Card hard drives — early professional
cameras thermal printer — known only in one
model of camera that printed images
immediately rather than storing.

15. PIXEL RESOLUTION OF A DIGITAL CAMERA
• The clarity of the photos taken from a digital
camera depends on the resolution of the
camera.
• This resolution is always measured in the
pixels.
• If the numbers of pixels are more, the
resolution increases, thereby increasing the
picture quality.
• There are many type of resolutions available
for cameras. They differ mainly in the price.

16. TYPES OF PIXELS
• 256×256 – This is the basic resolution a
camera has.
• 640×480-These type of cameras are suitable
for posting pics and images in websites.
• 1216×912 – This resolution is normally used in
studios for printing pictures.
• 2240×1680 – This is commonly referred to as a
4 megapixel cameras.
• There are even higher resolution cameras up
to 20 million pixels or so.

17. DESIGNER’S PERSPECTIVE
• Two key tasks
– Processing images and storing in memory
• When shutter pressed:
– Image captured
– Converted to digital form by charge-coupled device (CCD)
– Compressed and archived in internal memory
– Uploading images to PC
• Digital camera attached to PC
• Special software commands camera to transmit archived
images serially
17

18. CHARGE-COUPLED DEVICE (CCD)
• Special sensor that captures an image
• Light-sensitive silicon solid-state device composed of many cells
When exposed to light, each
cell becomes electrically The electromechanical
charged. This charge can Lens shutter is activated to expose
then be converted to a 8-bit the cells to light for a brief
area
value where 0 represents no Covered Electro- moment.
mechanical
exposure while 255 columns shutter
represents very intense The electronic circuitry, when
exposure of that cell to light. commanded, discharges the
Electronic
rows
Pixel
circuitry cells, activates the
Some of the columns are electromechanical shutter,
covered with a black strip of and then reads the 8-bit
paint. The light-intensity of charge value of each cell.
these pixels is used for zero- These values can be clocked
bias adjustments of all the Pixel out of the CCD by external
cells. columns logic through a standard
parallel bus interface.
18

19. • The light falling on a cell is converted into small
amount of electric charge which is measured by
electronics and stored as a number.

20. • On periphery screen is composed of
electromechanical shutter. When activated
screen opens momentarily and allows light to hit
the light sensitive surface.
• In a digital device, the voltages are sampled,
digitized, and usually stored in memory; in an
analog device (such as an analog video camera)
• They are processed into a continuous analog
signal (e.g. by feeding the output of the charge
amplifier into a low-pass filter) which is then
processed and fed out to other circuits for
transmission, recording, or other processing.

21. WHAT’S THE REAL DIFFERENCE
• Because each pixel on a CMOS • CCD sensors create high-
sensor has several transistors quality, low-noise images.
located next to it, the light CMOS sensors are generally
sensitivity of a CMOS chip is more susceptible to noise.
lower. Many of the photons hit
the transistors instead of the
photodiode.
• CMOS sensors traditionally • CCD sensors have been mass
consume little power. CCDs, on produced for a longer period of
the other hand, use a process time, so they are more mature.
that consumes lots of power. They tend to have higher
CCDs consume as much as 100
times more power than an quality pixels, and more of
equivalent CMOS sensor. them.

22. ZERO-BIAS ERROR
• Manufacturing errors cause cells to measure slightly above or below actual
light intensity
• Error typically same across columns, but different across rows
• Some of left most columns blocked by black paint to detect zero-bias error
– Reading of other than 0 in blocked cells is zero-bias error
– Each row is corrected by subtracting the average error found in blocked cells
for that row
Covered Zero
cells Bias
136 170 155 140 144 115 112 248 12 14 -13 123 157 142 127 131 102 99 235
145 146 168 123 120 117 119 147 12 10 -11 134 135 157 112 109 106 108 136
144 153 168 117 121 127 118 135 9 9 -9 135 144 159 108 112 118 109 126
176 183 161 111 186 130 132 133 0 0 0 176 183 161 111 186 130 132 133
144 156 161 133 192 153 138 139 7 7 -7 137 149 154 126 185 146 131 132
122 131 128 147 206 151 131 127 2 0 -1 121 130 127 146 205 150 130 126
121 155 164 185 254 165 138 129 4 4 -4 117 151 160 181 250 161 134 125
173 175 176 183 188 184 117 129 5 5 -5 168 170 171 178 183 179 112 124
Before zero-bias adjustment After zero-bias adjustment
22

23. COMPRESSION
• Store more images
• Transmit image to PC in less time
• JPEG (Joint Photographic Experts Group)
– Popular standard format for representing digital images in a
compressed form
– Provides for a number of different modes of operation
– Mode used provides high compression ratios using DCT (discrete
cosine transform)
– Image data divided into blocks of 8 x 8 pixels
– 3 steps performed on each block
• DCT
• Quantization
• Huffman encoding
23

24. DCT STEP
• Transforms original 8 x 8 block into a cosine-
frequency domain
– Upper-left corner values represent more of the essence of the image
– Lower-right corner values represent finer details
• Can reduce precision of these values and retain reasonable image quality
• FDCT (Forward DCT) formula
– C(h) = if (h == 0) then 1/sqrt(2) else 1.0
• Auxiliary function used in main function F(u,v)
– F(u,v) = ¼ x C(u) x C(v) Σx=0..7 Σy=0..7 Dxy x cos(π(2u + 1)u/16) x cos(π(2y + 1)v/16)
• Gives encoded pixel at row u, column v
• Dxy is original pixel value at row x, column y
• IDCT (Inverse DCT)
– Reverses process to obtain original block (not needed for this design)
24

25. QUANTIZATION STEP
• Achieve high compression ratio by reducing image
quality
– Reduce bit precision of encoded data
• Fewer bits needed for encoding
• One way is to divide all values by a factor of 2
– Simple right shifts can do this
– Dequantization would reverse process for
decompression
1150 39 -43 -10 26 -83 11 41 144 5 -5 -1 3 -10 1 5
-81 -3 115 -73 -6 -2 22 -5
Divide each cell’s -10 0 14 -9 -1 0 3 -1
14 -11 1 -42 26 -3 17 -38 value by 8 2 -1 0 -5 3 0 2 -5
2 -61 -13 -12 36 -23 -18 5 0 -8 -2 -2 5 -3 -2 1
44 13 37 -4 10 -21 7 -8 6 2 5 -1 1 -3 1 -1
36 -11 -9 -4 20 -28 -21 14 5 -1 -1 -1 3 -4 -3 2
-19 -7 21 -6 3 3 12 -21 -2 -1 3 -1 0 0 2 -3
-5 -13 -11 -17 -4 -1 7 -4 -1 -2 -1 -2 -1 0 1 -1
After being decoded using DCT After quantization
25

26. HUFFMAN ENCODING STEP
• Serialize 8 x 8 block of pixels
– Values are converted into single list using zigzag pattern
• Perform Huffman encoding
– More frequently occurring pixels assigned short binary code
– Longer binary codes left for less frequently occurring pixels
• Each pixel in serial list converted to Huffman encoded values
– Much shorter list, thus compression
26

27. HUFFMAN ENCODING EXAMPLE
• Pixel frequencies on left
– Pixel value –1 occurs 15 times
– Pixel value 14 occurs 1 time
• Build Huffman tree from bottom up
– Create one leaf node for each pixel value and assign frequency as node’s
value
– Create an internal node by joining any two nodes whose sum is a minimal
value
• This sum is internal nodes value
– Repeat until complete binary tree
• Traverse tree from root to leaf to obtain binary code for leaf’s
pixel value
– Append 0 for left traversal, 1 for right traversal
• Huffman encoding is reversible
27 – No code is a prefix of another code

28. Huffman codes
Pixel frequencies Huffman tree
64
-1 15x -1 00
0 8x 35
0 100
-2 6x 29
-2 110
1 5x 1 010
2 5x 2 1110
17
18
3 5x 15
14
3 1010
5 5x 5 0110
-1 11 -3 11110
-3 4x 9
10
5
8 6 -5 10110
-5 3x
1 0 -2 -10 01110
-10 2x
4 5 6 144 111111
144 1x 5 5 5
-9 1x 2 -9 111110
5 3
-8 1x 2 2 -8 101111
2 3 4
-4 1x 2 -4 101110
-10 -5 -3 6 011111
6 1x
1 1 1 1 1 14
14 1x 1 011110
14 -4 -8 -9 144
6

30. COMPONENTS OF CAMERA
1. Battery compartment: This camera takes two 1.5-volt
batteries, so it runs on a total voltage of 3 volts (3 V).
2. Flash capacitor: The capacitor charges up for several
seconds to store enough energy to fire the flash.
3. Flash lamp: Operated by the capacitor. It takes a fair bit
of energy to fire a xenon flash like this, which is why a lot of
indoor flash photography quickly uses up your batteries.
4. LED: A small red LED (light-emitting diode) indicates
when the self-timer is operating, so you can take photos of
yourself more easily.
5. Lens: The lens catches light from the object you're
photographing and focuses it on the CCD.
6. Focusing mechanism: This camera has a simple switch-
operated focus that toggles the lens between two positions
for taking either close-ups or distant shots.

31. 7. CCD: This is the light-detecting microchip in a digital
camera. You can't actually see the CCD in this photo, because it's
directly underneath the lens. But you can see what it looks like in
our article on how CCDs work.
8. USB connector: Attach a USB cable here and connect it to
your computer to download the photos you've taken. To your
computer, your camera looks like just another memory device
(like a hard drive or a flash memory).
9. SD (secure digital) card slot: You can slide a flash memory
card in here for storing more photos. The camera has a very
small internal memory that will store photos too.
10. Processor chip: The camera's main digital "brain". This
controls all the camera's functions. It's an example of an
integrated circuit.
11. Wrist connector: The strap that keeps the camera
securely tied to your wrist attaches here.
12. Top case: Simply screws on top of the bottom case shown
here.

32. BLOCK DIAGRAM

34. WHY PREFER ARM CORTEX M3?
• With high performance and low dynamic power
consumption the Cortex-M3 processor delivers leading
power efficiency 12.5 DMIPS / mW based on 90nmG.
• The processor executes Thumb®-2 instruction set for
optimal performance and code size.
• It including hardware division, single cycle multiply,
and bit-field manipulation.
• The Cortex-M3 NVIC is highly configurable at design
time to deliver up to 240 system interrupts.

36. FEATURES OF ARM CORTEX
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• Operating voltage:
2.7 to 3.6V (Single supply 3.0 to 3.45V when USB is used)
• Maximum Operating frequency:
48 MHz
• On-chip debug circuit:
JTAG, SWD, SWV or 4-bit trace interface
• Power saving operation
Clock gear (for dividing clock to 1/1, 1/2, 1/4, 1/8 or 1/16)
Standby modes (IDLE, STOP1)
• ARM cortex M is a group of 32 bit RISC processor cores
licensed by Arm holdings intended for microcontroller
applications
• 3 stage pipeline is used.

37. BUILT-IN FUNCTIONS
• USB(Full-Speed) : 1 channel
• 12-bit AD converter :
1µsec conversion time(@fsys=40MHz) 12 channels
• DMA controller : 2 channels
• I/O ports : 74 pins
• 16-bit timer : 10 channels
• SIO/UART : 2 channels
• I2C(100kHz,400kHz)/SIO : 2 channels

38. JOINT TEST ACTION GROUP (JTAG)
• It is the common name for the IEEE 1149.1
Standard Test Access Port and Boundary-Scan
Architecture.
• Today JTAG is also widely used for IC debug ports.
• On most systems, JTAG-based debugging is
available from the very first instruction after CPU
reset, letting it assist with development of early
boot software which runs before anything is set
up.

39. 16-BIT TIMER
• The TIMERS are divided into two 8-bit SFR called Timer
LOW (TL0, TL1) & Timer HIGH (TH0, TH1) these
registers contain the latest count of the TIMER.
• The TIMER action is controlled by two more SFR's
called Timer Mode Control Register(TMOD)
& Timer/Counter Control Register (TCON).
• TMOD is dedicated to the two Timers & controls the
mode of operation of both the Timers.
• It can be considered as two duplicate 4 bit register,
where the high 4 bits controls Timer 1 & the lower 4
bits controls Timer 0.

40. THE PHYSICAL I2C BUS
• This is just two wires, called SCL and SDA. SCL is the clock line. It is
used to synchronize all data transfers over the I2C bus.
• SDA is the data line. The SCL & SDA lines are connected to all
devices on the I2C bus.
• There needs to be a third wire which is just the ground or 0 volts.
There may also be a 5volt wire is power is being distributed to the
devices. Both SCL and SDA lines are "open drain" drivers. What this
means is that the chip can drive its output low, but it cannot drive it
high.
• For the line to be able to go high you must provide pull-up resistors
to the 5v supply. There should be a resistor from the SCL line to the
5v line and another from the SDA line to the 5v line.
• You only need one set of pull-up resistors for the whole I2C bus, not
for each device, as illustrated below:

43. SOFTWARE USED
Keil u vision (IDE).
• Tools:
Real View MDK-ARM, ULINK2 - USB-JTAG Debugger.
Real View Real-Time Library (RL-ARM).
• Types of Target Debugging, Serial Wire Debugger for
Cortex
CortexM3 – Core sight Debugger
ULINK2 - USB-JTAG Debug Adaptor

44. Future of Digital camera
• Smart camera- Application enhanced cameras
along with the ability to access various apps,
internet, compact like Galaxy camera
• Not only it gives a full interactive photographic
capabilities but also keeps you connected via
internet.
• You can directly post the pictures taken to
Facebook etc. along with interactive media . Its
just like a merged up high end smart phone with
a smart camera
• iris-cameras is at a developing stage everyone has
seen the glimpse of it in Mission impossible 4

45. THANK YOU