Multimedia Signal Processing

From Analog to Digital, from Continuous to Discrete

Sampling and quantization, the Fourier Series (FS), the Fourier Transform (FT), the Discrete-Time Fourier Transform (DTFT), and Fourier processing.

The z-Transform

The z-Transform and its relationship with the DTFT and DFT, pole-zero plots, and ad-hoc filter design.

Introduction to the DFT

DFT, IDFT, derivation of the DFT, and Fourier theorems for the DFT.

Introduction to Digital Filters

Time-domain representations, transfer-function analysis, and frequency-response analysis.

Windowing and STFT

Overview of windows, overlap-and-add, and the Short-Time Fourier Transform (STFT).

Digital Filter Design Techniques

Filter specifications, IIR filter design, and FIR filter design.

Introduction to Multirate Processing

Downsampling, upsampling, decimation, interpolation, polyphase filters, and perfect-reconstruction filter banks.

The proposed applications and exercises cover audio, image, and video signal processing and are mainly based on Python and MATLAB.

Laboratory activities complement the theoretical part of the course by providing practical examples of signal analysis, filtering, transforms, and multimedia processing techniques.

Structure of the Written Test

The exam for Multimedia Signal Processing — First Module and Fundamentals of Multimedia Signal Processing consists of three parts to be completed in 2 hours:

1. Numerical/procedural exercise.
   The first exercise requires a numerical or procedural solution and must be solved using only pen and paper.
2. Multiple-choice questions.
   The second part consists of a set of multiple-choice questions covering the theoretical and practical topics addressed during the course.
3. MATLAB programming exercise.
   The third exercise requires the definition of a MATLAB procedure to solve the proposed problem. The MATLAB code must be written directly on paper, without the use of a computer or any other electronic aid.

Written Examination Only

The examination for the first module is conducted only in written form. No oral examinations, supplementary oral assessments, integrations, or additional projects will be considered for increasing the obtained grade.

Students Taking Both Modules

Students enrolled in the complete Multimedia Signal Processing course, and therefore taking both the first and second modules, must obtain a positive grade in both modules in order to pass the overall examination.

The final grade is calculated as the average of the grades obtained in the two modules, rounded up to the next integer.

For the calculation of this average, a grade of 30 cum laude in one module is considered as 30.

In order to obtain 30 cum laude as the final grade, both module grades must be 30 and at least one of the two must be awarded cum laude.

Taking One or Both Modules

At each examination session, the exams for the two modules are normally held on the same day, one after the other. The exact timetable will be communicated to all students registered for the exam before the examination date.

For some examination sessions, a survey may be carried out among all registered students to determine whether any student intends to take both modules during the same session. If, and only if, no registered student intends to take both examinations, the two module exams may be held in parallel instead of consecutively. In such a case, all registered students will be informed in due time about the resulting examination schedule.

Students may choose either to take both modules during the same session or to take only one module and complete the other during a subsequent examination session within the same Academic Year.

Frozen Grades and Retaking a Module

Once a student obtains a positive grade in a module, that grade can be frozen and retained for a subsequent examination session, provided that the student explicitly refuses the published grade through the PoliMi Online Services during the official publication period. The frozen grade then remains valid until the student decides to retake the examination for the same module in a subsequent session.

Retaking a module means that the student:

• registers for the examination;
• participates in the examination;
• submits the completed examination paper.

If a student participates in an examination session but does not submit the examination paper, the previously obtained grade is not modified and the student is considered absent for that module.

Publication and Recording of the Final Grade

Once a positive grade has been obtained in both modules, the final grade is calculated and published through the PoliMi Online Services for the official publication period.

At the end of this period, the final grade is automatically recorded.

If a student does not wish to accept the final grade, it must be explicitly refused through the PoliMi Online Services. In this case, the grades obtained in the two modules return to the frozen state, allowing the student to retake one or both modules in a subsequent session.

Important: if a student has a frozen positive grade in both modules, the final average grade may be published again after an examination session for which the student has registered. Therefore, students wishing to improve their final grade must remember to refuse the published final grade through the Online Services; otherwise, at the end of the publication period, the grade will be automatically recorded.

Pre-exam

When a pre-exam is offered for the course, it represents a complete examination of the first module and is equivalent, in terms of contents, assessment criteria, and validity of the obtained grade, to a regular examination session.

The pre-exam is therefore simply an additional examination opportunity made available to students and does not involve any penalty or disadvantage compared with the regular examination sessions.

As for all regular examination sessions, registration for the pre-exam is mandatory. Students who are not properly registered will not be allowed to take the examination.

Students enrolled only in the first module (Fundamentals of Multimedia Signal Processing) should also remember that a grade obtained during the pre-exam cannot be directly recorded through the PoliMi Online Services. For purely administrative reasons, these students must therefore register for one of the subsequent official examination sessions in order to allow the grade obtained in the pre-exam to be formally recorded.