DIGITAL IMAGE DIGITAL IMAGE PROCESSINGPROCESSING

PRESENTED BYPRESENTED BY

T.PravallikaT.Pravallika

S.mdS.md ....NoorNoor ZebaZeba

IMAGE PROCESSINGIMAGE PROCESSING

• Enhancing Image.Enhancing Image.

• Extracting information & Features.Extracting information & Features.

• Manipulation & Alteration of Manipulation & Alteration of images.images.

DIGITAL IMAGEDIGITAL IMAGE

• Two dimensional representation of values.Two dimensional representation of values.• These are called “These are called “PIXELSPIXELS ”.”.• Pixels are stored in computer memory.Pixels are stored in computer memory.

DIGITAL IMAGE DIGITAL IMAGE PROCESSINGPROCESSING

• The processing done by using Computer The processing done by using Computer software.software.

• Avoids build-up of noise and signal distortion.Avoids build-up of noise and signal distortion.

Reasons For Introducing Digital Reasons For Introducing Digital Image ProcessingImage Processing

•For better improved image•Use in space technologies like NASA•Crime Departments like FBI•Better editing features

How can we process an How can we process an Image?Image? • Transfer image to a computerTransfer image to a computer• Digitize the imageDigitize the image

* Digitization – translating image into * Digitization – translating image into numerical code understood by computer.numerical code understood by computer.

• Processing can be done through software programs in Processing can be done through software programs in a “a “Digital Dark-roomDigital Dark-room””

• Image is broken down into thousands of pixelsImage is broken down into thousands of pixels

Types of ImagesTypes of Images

Binary Image:Binary Image:• Takes two possible values ( 0 or 1) for a Takes two possible values ( 0 or 1) for a

pixelpixel• Bi-level or Two-levelBi- level or Two-level

Gray Scale Image:Gray Scale Image:• Pixel takes a single sample from range of Pixel takes a single sample from range of

valuesvalues

* Voxel - data associated to points * Voxel - data associated to points scattered over a 3-dimensional region scattered over a 3-dimensional region (produced by Tomographic equipment)(produced by Tomographic equipment)

Color Image:Color Image:• Color information is included for each Color information is included for each

pixel .pixel .• 3 samples should be provided for each 3 samples should be provided for each

pixel .pixel .• RGB is commonly used color space. RGB is commonly used color space.

(YUV, HSV are used in some other (YUV, HSV are used in some other context)context)

Original Black & White

Gray Scale

False ColorFalse Color• These are derived from the grey scale These are derived from the grey scale

images.images.• Also cal led as “Pseudo Color Images”Also cal led as “Pseudo Color Images”• Doesn't increases the information Doesn't increases the information

contents but improves the details .contents but improves the details .• Mainly used in fie lds of satel l ite imagesMainly used in fie lds of satel l ite images

False color

True Color

Categories Of Image Categories Of Image ProcessingProcessing

• Image compressionImage compression

• EnhancementEnhancement

• Measurement ExtractionMeasurement Extraction

Digital Image EditingDigital Image Editing

• Process of altering digital imagesProcess of altering digital images..

Basics of Digital Image EditingBasics of Digital Image Editing• Pixels contain image’s color and brightness Pixels contain image’s color and brightness

information.information.• Image editors can change the values of pixels to Image editors can change the values of pixels to

enhance the image.enhance the image.• Various basic “Image editing programs” are readily Various basic “Image editing programs” are readily

available with the device itself.available with the device itself.

Image Editor FeaturesImage Editor FeaturesImage s ize alterationImage s ize alteration

• Image editors can resize an image by altering the Image editors can resize an image by altering the resolution.resolution.

• Re-sampling is done to calculate new resolution.Re-sampling is done to calculate new resolution.

Cropping an Image

•Cropping means creating a new image by selecting a desired rectangular portion.

Noise RemovalNoise Removal• Image editors have algorithms to add and remove noise like Image editors have algorithms to add and remove noise like

dust and scratches & image can be despeckled.dust and scratches & image can be despeckled.

Removal of Unwanted ElementsRemoval of Unwanted Elements• Can be done by “Clone” toolCan be done by “Clone” tool

Original Removal of unwanted branch at the top of the image

Selective Color ChangeSelective Color Change• Ability to selectively change the color.Ability to selectively change the color.

An example of se lective color change, the or iginal is on the r ight

Merging of ImagesMerging of Images• One or more images can be merged into a single One or more images can be merged into a single

picture.picture.

John and Bertha Phil l ips - 1910

Special EffectsSpecial Effects• Used to create unusual imagesUsed to create unusual images• Images can be skewed & distorted in various ways Images can be skewed & distorted in various ways

like artistic effects, geometric & texture effects etc.like artistic effects, geometric & texture effects etc.

Change Color DepthChange Color Depth• Common color depths are 2, 16, 256 & 16 million Common color depths are 2, 16, 256 & 16 million

colors.colors.• Gray scale images can be created from full color Gray scale images can be created from full color

images through conversion & down sampling.images through conversion & down sampling.

An example of converting an image from color to grayscale

Lens CorrectionLens Correction• Various lens distortions like pincushion, fish eye & Various lens distortions like pincushion, fish eye &

barrel distortions can be corrected.barrel distortions can be corrected.

Contrast Change & BrighteningContrast Change & Brightening• Change the contrast of images & brighten or darken Change the contrast of images & brighten or darken

the images.the images.• Pixels below particular luminosity can be Pixels below particular luminosity can be

brightened.brightened.

Sharpening & Softening ImagesSharpening & Softening Images• Images can be sharpen or blurred like ‘edge Images can be sharpen or blurred like ‘edge

enhancement’enhancement’

Color AdjustmentsColor Adjustments• Color balance can be improvedColor balance can be improved

ADVANTAGESADVANTAGES• Post processingPost processing• Electronic transmissionElectronic transmission• Chemical freeChemical free• Reduction of radiation exposureReduction of radiation exposure

DISADVANTAGESDISADVANTAGES

•ExpensiveExpensive•Sometimes vagueSometimes vague

CONCLUSIONCONCLUSION

Image editors provide the means of Image editors provide the means of altering and improving images in altering and improving images in

endless number of ways.endless number of ways.

Thank ‘U’...Thank ‘U’...

QUERIES…QUERIES…