For many years, film cameras were the only option for capturing cinema quality motion pictures. The time requirements and costs related to shooting and processing motion picture images on film stock and then transferring those images into a digital form have created a need for motion picture cameras that capture high definition or cinema resolution imagery directly in a digital form. The advent of Digital Cinemas, cost effective Stereo 3D Digital cinema projection systems and establishment of Digital Cinema Initiative SMPTE Standards has fueled the need for more content creation for delivery at 2K, 4K and Stereo formats.
Accordingly, there is a need for a digital camera system that meets the needs described above that reduces costs. There is also a need for a digital camera system that leverages digital processing and visualization tools. There is a further need for a digital camera system that provides user feedback and metadata collection when shooting special effects, compositions and stereo or multi-camera content. There is an additional need for a digital camera system that improves flexibility in networked collaboration, enables separated imaging block and recording, has a simple workflow with metadata management and, importantly, maintains film-like reproduction qualities and camera operation. There is also a need for a digital camera system that not only provides the capabilities described above but can also utilize existing cabling infrastructure, broadcast signal monitoring and transmission systems. There is a need for a digital camera system that mixes broadcast standard digital sources into a recording and visualization system, as well as generate broadcast standard and network streaming outputs for 2D and 3D content.
In the past few years, while several digital cinema cameras have emerged on the market these digital cinema cameras are complex designs with limited connectivity that are only able to address a limited set of the needs described above. For example, these digital cinema cameras are incompatible with existing cable infrastructure. Also, these digital cinema cameras either completely lack network management or are capable of only minimal network management (i.e., only simple controls that lack full image streaming or metadata management). Further, these digital cinema cameras lack the ability to capture or record multi-sensor 2K or 4K image data using a single control application. Additionally, these digital cinema cameras lack visualization tools or metadata integration. These digital cinema cameras do not utilize existing broadcast infrastructure to transmit multi-resolution data and have complex workflows with respect to stereo 3D and multi-camera content acquisition, broadcast and network transmission either live or in a post production process. These digital cinema cameras are limited to 1920×1080 image sensor pixel arrays that require the use of a multiple sensor prism block which, in turn, requires use of complex and expensive optics. These digital cinema cameras utilize dedicated hardware functions with no or limited image processing flexibility or upgrade capability. Dedicated hardware functions utilized by these digital cinema cameras include video processing to perform non-reversible color space transformations or sub-sampling to formats, such as YUV 4:2:2 and 4:4:4, as standard broadcast signals. These digital cinema cameras implement a variety of proprietary compression and coding schemes that introduce visible image artifacts, especially when projected on large screens. While a number of these digital cinema cameras can generate preview imagery for display on an electronic viewfinder, these digital cinema cameras can only do so with limited resolution or visualization tools. High-resolution outputs from these digital cinema cameras are restricted to transmission in SMPTE standard resolution and formats. These digital cinema cameras often output imagery to be record on restrictive, proprietary or large external storage devices. These storage devices include a tape storage system having only linear data access, Non-Volatile Flash or RAM drives with limited storage, and multiple hard disk drive RAID storage systems which are often non-portable and whose media cannot be easily removed or transported for direct use in other systems. Also, the files stored on these storage devices have limited color correction, image processing or post production metadata integration.
In recent years, many digital still cameras or dual-mode video and still camcorders have also been developed which use single image sensors with color filter arrays. These digital still cameras and camcorder devices do use higher resolution sensors (e.g., HD (1920×1080) camcorders, digital single-lens reflex camera (DSLR) are now 10 MP and higher). However, these digital still cameras and camcorders have slow readout architectures (e.g., a DSLR may only shoot four (4) frames per second) and can only achieve video rate preview at low resolution (e.g., 640×480) or standard definition (e.g., VGA 640×480 at thirty (30) frames per second) using sub-sampling or windowing techniques. These digital still cameras and camcorders use dedicated hardware functions or targeted function digital signal processors (DSP) to perform image processing to interpolate and colorize the raw image data from the image sensor. These digital still cameras and camcorders compress the colorized images for storage; but the compressing process performed by these devices prevents access to the original full raw image pixel data for later processing, analysis or colorization. In addition, the interpolation and color processing applied to the source raw data in those devices initially generates data sets that are larger than the source raw data which, in turn, requires the application of higher compression to fit the data sets into a target storage capacity. This typically results in a reduction in image quality compared to the original image or a coded version of the raw data.
A few single sensor cameras have been developed for use in 2K and 4K acquisitions in raw format. However, these cameras use dedicated hardware or targeted function DSPs to perform image processing to interpolate, colorize and display preview quality output and simultaneously compress the raw sensor image data for later digital editing and grading. Also, the compression method and metadata employed by these cameras foreclose the dynamic retrieval of alternative resolution or representations at different bit rates during recording for network streaming, remote grading or adaptive editing. Due to their architectures, these single sensor cameras must apply high compression to fit data into target internal storage capacity devices. Also, due to their architectures, these single sensor cameras lack the ability to transmit the imager raw content over existing broadcast or network infrastructure cabling for remote monitoring, networking, recording or visualization. These single sensor cameras cannot process captured signals with prerecorded content or broadcast format signals for live composition, switching, grading, mixing into virtual sets or adding graphic overlays based on extracted metadata or analytics. These single sensor cameras also lack the ability to manage, control or record multi-sensor imagers, which may be remotely connected to a recording system.
In recent years, there has been an interest in producing digital cinema quality 3D stereographic, wide-dynamic and immersive content using multiple imagers. This has created a need for more efficient modular and scalable cameras and workflow solutions. There is a further need for a digital camera system having a precise synchronization mechanism to enable images to be mixed or stitched without motion artifacts. While digital camera systems have been used to produce this type of content, these camera systems suffer from the same system limitations as the cameras described above. These camera systems are mostly comprised of stand-alone cameras, each with individual controls, viewing and recording systems, with no integration mechanism other than a common sync signal (i.e., there is no communication between camera controls or viewing and recording settings). These camera systems are large and bulky such that the camera systems cannot be placed very close together physically, as is required for short inter-ocular distances in 3D stereographic or for creating hemispherical views where cameras need to be placed as close together as possible from a common center point. When shooting thru mirrors and beam splitters, rigs (i.e., a combination of digital cameras, optics and mounting platform) become more cumbersome and difficult to use in handheld shooting environments. Finally, these camera systems lack a comprehensive set of image processing, visualization, positioning control, recording, playback, communications and display tools for use in such high-definition multi-camera systems.