We present a novel High-Dynamic-Range (HDR) image sensor with linear output. Photogenerated charge is continuously every pixel without saturating. Each time the integrated at photodiode voltage reaches a programmable threshold, the pixel resets and starts over integrating charge again. With an eventbased approach, it is possible to count the number of times (if any) that a pixel has saturated during exposure. Pixel illumination is represented with a 20-bit word. The most significant 12b represent the number of times that a pixel has saturated during exposure. The least significant 8b are the result of an analog-todigital conversion in the end of exposure. Thus, pixels provide linear outputs proportional to light intensity. A dynamic range of 120dB is expected. The maximum dynamic range that can be measured is limited by the maximum event rate that the chip peripheral circuitry can handle and by the space dedicated on memory to store the event information. Pixel pitch is 25μm. A prototype sensor with 128 x 96 pixels has been implemented in the AMS 180nm CMOS-HV technology. In this article, the pixel operation will be explained. Preliminary experimental results and snapshots will be also provided.