Testing Q-Former Text-to-Image: Gradients through Frozen Backbones | CMU 10-423 Assignment 4
Use an original numerical test to check gradients, data, and evaluation alongside the original assignment specification.
Use an original numerical test to check gradients, data, and evaluation alongside the original assignment specification.
“Text plus images” does not specify the task. Text-to-image generation produces an image conditioned on text; a VLM may consume an image and produce an answer. Direction, output objective, and evaluation differ even when both use Transformers.
L11 fills in the rest of the Stable Diffusion diagram. CLIP is trained so that matching text and images get similar vectors, which turns a prompt into a 77×768 embedding. Schedulers compress 1,000 noising steps into twenty or thirty denoising steps, but ancestral samplers such as Euler a never settle: push to 100 steps and the subject changes jackets and seats. LoRA freezes the original W and learns only a ΔW factored into A·B. The hands-on part loads an SD 1.5-family model with diffusers, and the week 11 homework is your own image-generation web app.
The key to conditional generation is 'feed y into the model': cGAN concatenates y into G/D; cVAE passes y to both encoder and decoder; in diffusion, Classifier Guidance uses gradients from an external classifier to push samples toward a class, while Classifier-Free Guidance trains conditional + unconditional together and linearly combines them at inference — the latter is the standard weapon behind Stable Diffusion and Imagen.
2022 marked computer vision’s turn from recognition toward generation. Latent Diffusion Models appeared at CVPR and led to Stable Diffusion; NeRF research jumped from 25 papers in 2021 to more than 50 at CVPR alone; ConvNeXt mounted a compelling counterattack for CNNs; and ECCV in Tel Aviv set a record with 157 oral papers.