Lab 6: Sound/Image Synthesis Solution

In this lab, you will synthesize a sound or an image digitally, from scratch or by modifying and combining existing signals, using at least three of the following EE341 concepts:

simple signal synthesis (e.g. tones, random noise) time (or space) scaling, including reversal

amplitude operations (e.g. multiplication or addition of signals) ltering

convolution (e.g. for simulating reverberration) frequency shifting or other types of modulation

You may concatenate di erent sounds/images together, but this doesn’t count as one of the three EE341 concepts. You can reuse code that you developed in your earlier labs, but you must change it in some way. For example, if you do multiplication, create a function di erent from the ADSR envelope you used in lab 2. If you do ltering, use a lter that is di erent from what you implemented in labs 3 and 5.

Do not use sounds or images that may be o ensive, e.g., no profanity or pornography. The class will vote for their favorites in each category, and the winner in each category

will get a bonus point. Participating in voting will be worth 2 points as a class assignment, due in class, Friday 3/9.

You may do this lab in groups of 2-3 people, but only the submissions created by indi-viduals will be eligible for winning a bonus point. Winners will be asked to explain to the class how you created your sound or image.

Option A: Music or Sound E ect Synthesis

Compose a short piece of music or a sound e ect. You can use any of the sound les made available on the class web page or search the web for reusable sound les or record a sound yourself. (Do not use recordings of others without their permission.) You can also synthesize sounds using sinusoids or random noise (as in lab 2), square waves, etc. Apply signal processing techniques to one or more component sounds, separately or in combination. The nal signal should be 10-20 seconds in length.

Each signal processing technique should have an audible e ect. For example, if you synthesize notes as in lab 2 and apply a lter the includes all notes, that would not have an audible e ect.

Make sure you pay attention to any di erences between the sampling rates of the sound les you use or generate, since the nal output will be based on only a single sampling rate.

When you are satis ed with your composition, save it as a .wav le. It is a good idea to check that there were no write problems by listening to that le.

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Option B: Image Synthesis

Create a synthetic image, an image collage or modify a color image. You can use your own images/photos or search the web for reusable images. (Do not use copyrighted images without permission.) You can also synthesize images patterns using the same techniques as for sounds above but with two dimensions, e.g. a square wave in two dimensions should give you a checkerboard, and random noise in two dimensions will give you a speckled pattern. Apply signal processing techniques to one or more component images, separately or in combination. The nal image should be a size that will be easily viewed on a laptop screen.

It is ne to work with grayscale images, which you can get using the rgb2gray command in Matlab. However, if you want to work with color images, you can do that by separately processing each of the three color planes as its own image (see background discussion of lab 2). Remember that image pixels take values in the [0,255] range.

You may use code that you developed for lab 2, but you must also use some processing beyond what was explored in that lab.

When you are satis ed with your creation, write it out to a .jpg or .png le using the imwrite command. View the le to make sure it is your nal version.

Multimedia:

Occasionally, students are interested in combining image and audio processing. If you would like to do this, please run your idea by the professor in advance. Any multimedia submissions will be judged with the images.

Turn in to Canvas:

Your image or sound le (give it a lename that does not include your name but is more unique than \myimage" or \mysong")

A brief written description of the techniques and sounds/images used in your creation. For example, if you use ltering, specify the lter design. If you use convolution, describe how you generated (or found) the impulse response. If you use time scaling, specify the scale factor(s).

Zip  le of MATLAB scripts used to generate your sound/image.

















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