Product VIII: Image Extender

Iterative Workflow and Feedback Mechanism

The primary objective for this update was to architect a paradigm shift from a linear generative pipeline to a nonlinear, interactive sound design environment

System Architecture & Implementation of Interactive Components

The existing pipeline, comprising image analysis (object detection, semantic tagging), importance-weighted sound search, audio processing (equalization, normalization, panoramic distribution based on visual coordinates), and temporal randomization was extended with a state-preserving session layer and an interactive control interface, implemented within the collab notebook ecosystem.

Data Structure & State Management
A critical prerequisite for interactivity was the preservation of all intermediate audio objects and their associated metadata. The system was refactored to maintain a global, mutable data structure, a list of processed_track objects. Each object encapsulates:

  • The raw audio waveform (as a NumPy array).
  • Semantic source tag (e.g., “car,” “rain”).
  • Track type (ambience base or foreground object).
  • Temporal onset and duration within the mix.
  • Panning coefficient (derived from image x-coordinate).
  • Initial target loudness (LUFS, derived from object importance scaling).

Dynamic Mixing Console Interface
A GUI panel was generated post-sonification, featuring the following interactive widgets for each processed_track:

  • Per-Track Gain Sliders: Linear potentiometers (range 0.0 to 2.0) controlling amplitude multiplication. Adjustment triggers an immediate recalculation of the output sum via a create_current_mix() function, which performs a weighted summation of all tracks based on the current slider states.
  • Play/Stop Controls: Buttons invoking a non-blocking, threaded audio playback engine (using IPython.display.Audio and threading), allowing for real-time auditioning without interface latency.

On-Demand Sound Replacement Engine
The most significant functional addition is the per-track “Search & Replace” capability. Each track’s GUI includes a dedicated search button (🔍). Its event handler executes the following algorithm:

  1. Tag Identification: Retrieves the original semantic tag from the target processed_track.
  2. Targeted Audio Retrieval: Calls a modified search_new_sound_for_tag(tag, exclude_id_list) function. This function re-executes the original search logic, including query formulation, Freesound API calls, descriptor validation (e.g., excluding excessively long or short files), and fallback strategies—while maintaining a session-specific exclusion list to avoid re-selecting previously used sounds.
  3. Consistent Processing: The newly retrieved audio file undergoes an identical processing chain as in the initial pipeline: target loudness normalization (to the original track’s LUFS target), application of the same panning coefficient, and insertion at the identical temporal position.
  4. State Update & Mix Regeneration: The new audio data replaces the old waveform in the processed_track object. The create_current_mix() function is invoked, seamlessly integrating the new sonic element while preserving all other user adjustments (e.g., volume levels of other tracks).

Integrated Feedback & Evaluation Module
To formalize user evaluation and gather data for continuous system improvement, a structured feedback panel was integrated adjacent to the mixing controls. This panel captures:

  • A subjective 5-point Likert scale rating.
  • Unstructured textual feedback.
  • Automated attachment of complete session metadata (input image description, derived tags, importance values, processing parameters, and the final processed_track list).
    This design explicitly closes the feedback loop, treating each user interaction as a potential training or validation datum for future algorithmic refinements.
  • Automated sending of the feedback via email

David Adlberger is a sound designer and media artist based in Graz. With a technical background and a Bachelor’s degree in Media Technology from FH St. Pölten, he is currently pursuing a Master’s degree in Sound Design at FH Joanneum and Kunstuniversität Graz. His work explores the intersection of narrative, technology, and perception. Fascinated since childhood by the creation of sonic worlds, he combines technical and artistic experimentation. His practice ranges from film sound and immersive 3D audio to algorithmic composition and audiovisual installations.
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