You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: A Survey of Efficient Regression of General-Activity Human Poses from Depth Images 
Chapter Title:  Introduction 
1. Abstract of Cited Paper (BIB001):  Thank you very much for downloading decision forests for computer vision and medical image analysis. As you may know, people have search hundreds times for their favorite readings like this decision forests for computer vision and medical image analysis, but end up in harmful downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they cope with some malicious bugs inside their computer.

Literature Review:
Human pose estimation from images has been studied for decades in computer vision. As recent development in cameras and sensors, depth images receive a wide spread of notice from researchers from body pose estimation 1 to 3D reconstruction 2 . Girshick et al. BIB001 present an approach to find the joints position in human body from depth images. They address the problem of general-activity pose estimation. Their regression-based approach sucessfully computes the joint positions even with occlusion. Their method can be view as a new combination of two existing works, implicit shape models  and Hough forest BIB002 . The following sections cover related works, explanation on the method from testing to training, and result and comparison.