IMAGE PROCESSING DIGITAL IMAGE FUNDAMENTALS By DR FERDA

IMAGE PROCESSING DIGITAL IMAGE FUNDAMENTALS By DR. FERDA ERNAWAN Faculty of Computer Systems & Software Engineering ferda@ump. edu. my OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Today’s Lesson • This lesson will cover: – Human visual system – Light and the electromagnetic spectrum – Image representation, image acquisition, image sensing – Sampling, quantisation and resolution – Digital image and pixels • Learning Outcomes: – To introduce fundamental of digital image processing. – Expose image acquisition process – Familiar with Digital image & pixels OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

The Human Visual System (HVS) • HVS is one of the most complex systems in existence. The visual system consists of an eye that transforms light into neural signals, and the related parts of the brain that process the neural signals and extract necessary information. • Light enters the cornea, passes through the aqueous humor, then the lens into the vitreous humor and finally onto the photoreceptors located at the back of the retina. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Structure Of The Human Eye q The cornea covers both the pupil and the iris. This is the first and most powerful lens of the optical system of the eye, together with the crystalline lens the production of a sharp image at the retinal photoreceptor level. q The cornea and lens act together like a camera lens to focus an image on the retina at the back of the eye. Horizontal section of the human eye OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Electromagnetic Spectrum OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Brightness and Contrast q Brightness is the psychological concept or sensation associated with the amount of light stimulus (Jayaraman, Veerakumar, Esakkirajan, 2017). Light source intensity depends upon the total light emitted and the size of the solid angle from which it is emitted. q Contrast is used to emphasise the difference in luminance of object (Jayaraman, Veerakumar, Esakkirajan, 2017). OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Brightness Adaptation Mach bands OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Brightness Adaptation OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Simultaneous Contrast Illustration of simultaneous contrast The perceived brightness of a surface depends upon the local background which illustrated in Figure above. The small square on the left-hand side appears brighter when compared to the brightness of the square on the right-hand side, even though the gray level of both the squares are the same. Simultaneous contrast can make the same colors look different. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Optical Illusions OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Image Representation q A digital image consists of pixel values of rows and columns col q The range pixel values are 0255 (black-white), 8 -bit per pixel. q An image is represented as matrices. f (row, col) row OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Image Acquisition A digital mage is obtained by illuminating a scene and absorbing the energy reflected. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Image Acquisition Images taken from Gonzalez and Woods, 2016 • A digital sensor measures samples at a discrete of energy levels. • Quantisation in image acquisition is a process to convert a continuous analogue signal into a digital signal OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Image Sampling OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Image Sampling: Digitized the coordinate values. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Quantization in Image Acquisition Sampling: Digitized the coordinate values. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Digital Image Quantization : Digitized the amplitude values, gray levels are converted to discrete values OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Spatial Resolution q Image resolution is obtained by the sampling process. q Spatial resolution represents the smallest information detail in image. 5. 1 ixels p a g Me OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 Resolution OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Images taken from Gonzalez and Woods, 2016 OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

What we’ll discuss… • Pixels: – Resolution – Color • File formats • Hardware & Software OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Digital Images and Pixels Digital Images are composed of digital elements called pixels. • Pixels are bundles of digital information about the color of a specific spot in the image. • They are organized into a grid to convey the image. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Patterns of dots produce the effects of consistent color The size of each pixel is determined by print size. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Digital Images and Pixels The RESOLUTION is the ratio of the number of PIXELS to the PRINT size. Resolution = # of pixels on the longest side print size Resolution is • used to judge the quality of the image. • Most often measured in pixels (or dots) per inch or ‘ppi’. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

The Big Picture =. 5 x. 75 @ 72 dpi; 6. 5 kb 4 x 5 @ 10 dpi 6. 5 kb OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

The Big Picture =. 5 x. 75 @ 575 dpi; 113 kb 4 x 5 @ 72 dpi 113 kb OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Print Quality Good consumer printers can print up to about 275 ppi. Commercial printers are often much better. 300 dpi is a print industry standard. The human eye usually can’t appreciate detail higher than 300 dpi from about 8 inches distance OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

Monitor Quality Regardless of the print size you dictate, the monitor will always display 72 pixels in each inch (unless your browser program creates a temporary view). If you scan something at 300 ppi and show it on a monitor, it will be resized to 72 ppi meaning a 5 inch image would be 21 inches. These images look as good as print images to your eye because of optical illusion OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.

References • R. C. Gonzalez and R. E. Woods, 2016. Digital Image Processing, Pearson Education India; Third edition. • A. K. Jain, 2015. Fundamentals of Digital Image Processing, Pearson Education India; First edition. • R. C. Gonzalez, R. E. Woods and S. L. Eddins, 2017. Digital Image Processing Using MATLAB. Mc. Graw Hill Education; 2 edition. • S. Jayaraman, T. Veerakumar, S. Esakkirajan, 2017. Digital Image Processing, Mc. Graw Hill Education; 1 edition. OER Digital Image Processing by Ferda Ernawan (editor) work is under licensed Creative Commons Attribution. Non. Commercial-No. Derivatives 4. 0 International License.